{"id":1238,"date":"2025-09-16T14:24:13","date_gmt":"2025-09-16T06:24:13","guid":{"rendered":"https:\/\/eve2333.top\/?p=1238"},"modified":"2025-09-16T14:24:14","modified_gmt":"2025-09-16T06:24:14","slug":"%e8%ae%be%e8%ae%a1%e6%a8%a1%e5%bc%8f-%e8%a3%85%e9%a5%b0%e5%99%a8%e6%a8%a1%e5%bc%8f","status":"publish","type":"post","link":"https:\/\/eve2333.top\/?p=1238","title":{"rendered":"\u8bbe\u8ba1\u6a21\u5f0f–\u88c5\u9970\u5668\u6a21\u5f0f"},"content":{"rendered":"\n

 \u88c5\u9970\u5668\u6a21\u5f0f\uff0c\u6700\u5e38\u7528\u7684\u8bbe\u8ba1\u6a21\u5f0f\u4e4b\u4e00<\/p>\n\n\n\n

\u8fd9\u662f\u4e00\u4e2a\u65b0\u7684\u5de5\u7a0b\u3002\u6211\u4eec\u6709\u4e00\u4e2a\u7c7b\u53eb\u505a `HistorySet`\uff0c\u5b83\u5e26\u6709\u4e00\u4e2a\u6cdb\u578b\u53c2\u6570\uff0c\u8868\u793a\u96c6\u5408\u4e2d\u7684\u5143\u7d20\u7c7b\u578b\u3002\u8fd9\u4e2a\u96c6\u5408\u65e2\u50cf\u666e\u901a\u7684 `Set` \u4e00\u6837\u652f\u6301\u589e\u5220\u6539\u67e5\uff0c\u53c8\u80fd\u5728\u5143\u7d20\u88ab `remove` \u6389\u7684\u65f6\u5019\u4fdd\u7559\u5386\u53f2\u8bb0\u5f55\u3002<\/p>\n\n\n\n

\u6211\u4eec\u5148\u601d\u8003\u5982\u4f55\u5b9e\u73b0\u8fd9\u4e2a\u529f\u80fd\u3002\u65e2\u7136\u5b83\u662f\u4e00\u4e2a `Set`\uff0c\u6211\u4eec\u53ef\u4ee5\u76f4\u63a5\u5b9e\u73b0 `Set<E>` \u63a5\u53e3\uff0c\u7136\u540e\u5b9e\u73b0\u5176\u4e2d\u7684\u6240\u6709\u65b9\u6cd5\u3002\u4e0d\u8fc7\u6211\u4eec\u91cd\u70b9\u5173\u6ce8\u7684\u662f `remove` \u65b9\u6cd5\u2014\u2014\u5982\u4f55\u5728\u5220\u9664\u5143\u7d20\u7684\u540c\u65f6\uff0c\u8bb0\u5f55\u4e0b\u88ab\u5220\u9664\u7684\u5143\u7d20\uff1f<\/p>\n\n\n\n

\u6211\u4eec\u53ef\u4ee5\u7528\u4e00\u4e2a `List<E>` \u6765\u4fdd\u5b58\u8fd9\u4e9b\u88ab\u5220\u9664\u7684\u5143\u7d20\uff0c\u6bd4\u5982\u547d\u540d\u4e3a `removedList`\u3002\u5f53\u4e00\u4e2a\u5143\u7d20\u6210\u529f\u4ece\u96c6\u5408\u4e2d\u79fb\u9664\u540e\uff0c\u6211\u4eec\u5c31\u628a\u8fd9\u4e2a\u5143\u7d20\u6dfb\u52a0\u5230 `removedList` \u4e2d\u3002<\/p>\n\n\n\n

public class HistorySet<E> implements Set<E> {\n\n    List<E> removeList = new ArrayList<>();\n\n    @Override\n    public int size() {\n        return 0;\n    }\n\n    @Override\n    public boolean isEmpty() {\n        return false;\n    }\n\n    @Override\n    public boolean contains(Object o) {\n        return false;\n    }\n\n    @Override\n    public Iterator<E> iterator() {\n        return null;\n    }\n\n    @Override\n    public Object[] toArray() {\n        return null;\n    }\n    @Override\n    public boolean remove(Object e){\n        return false;\n    }\n    @Override \n    public boolean containsAll(Collecction<?> c){\n        return false;\n    }\n    @Override\n    public void clear(){\n    }\n    @Override\n    public String toString(){\n        return hashSet.toString() +\" remove list: \" + removeList;\n    }\n}<\/code><\/pre>\n\n\n\n
\u73b0\u5728\u7684\u95ee\u9898\u662f\uff1a\u5982\u4f55\u5b9e\u73b0 `Set` \u63a5\u53e3\u7684\u5176\u4ed6\u65b9\u6cd5\uff1f\u5982\u679c\u6211\u4eec\u6709\u4e00\u4e2a\u5df2\u7ecf\u5b9e\u73b0\u4e86 `Set` \u63a5\u53e3\u7684\u7c7b\uff08\u6bd4\u5982 `HashSet`\uff09\uff0c\u80fd\u4e0d\u80fd\u628a\u6240\u6709\u529f\u80fd\u90fd\u59d4\u6258\u7ed9\u5b83\u6765\u5b8c\u6210\uff0c\u800c\u6211\u4eec\u53ea\u9700\u8981\u5728\u5173\u952e\u7684\u5730\u65b9\uff08\u5982 `remove`\uff09\u505a\u589e\u5f3a\u5904\u7406\uff1f<\/p>\n\n\n\n
\u7b54\u6848\u662f\u53ef\u4ee5\u7684\u3002\u6211\u4eec\u5728 `HistorySet` \u5185\u90e8\u6301\u6709\u4e00\u4e2a `Set<E>` \u7684\u5b9e\u4f8b\uff0c\u6bd4\u5982
private Set<E> hashSet =new HashSet<>();<\/p>\n\n\n\n
\u8fd9\u6837\uff0c`size()` \u5c31\u76f4\u63a5\u8fd4\u56de `hashSet.size()`\uff0c`isEmpty()` \u8fd4\u56de `hashSet.isEmpty()`\uff0c`add()` \u76f4\u63a5\u8c03\u7528 `hashSet.add()`\uff0c\u5176\u4ed6\u65b9\u6cd5\u4e5f\u90fd\u4ea4\u7ed9\u8fd9\u4e2a\u5185\u90e8\u7684 `HashSet` \u53bb\u5b8c\u6210\u3002<\/p>\n\n\n\n
\u552f\u72ec `remove` \u65b9\u6cd5\u6211\u4eec\u9700\u8981\u7279\u6b8a\u5904\u7406\u3002\u56e0\u4e3a `remove` \u6709\u8fd4\u56de\u503c\uff1a\u5982\u679c\u8fd4\u56de `true`\uff0c\u8bf4\u660e\u5143\u7d20\u786e\u5b9e\u88ab\u79fb\u9664\u4e86\uff1b\u5982\u679c\u8fd4\u56de `false`\uff0c\u8bf4\u660e\u5143\u7d20\u539f\u672c\u5c31\u4e0d\u5728\u96c6\u5408\u4e2d\uff0c\u65e0\u9700\u5904\u7406\u3002\u56e0\u6b64\uff0c\u6211\u4eec\u5148\u8c03\u7528 `hashSet.remove(o)`\uff0c\u5224\u65ad\u8fd4\u56de\u503c\uff1a<\/p>\n\n\n\n
@Override\npublic boolean remove(Object o) {\n    if(hashSet.remove(o)){\n        removeList.add((E)o);\n        return true;\n    }\n    return false;\n}\n<\/code><\/pre>\n\n\n\n
\u6ce8\u610f\u8fd9\u91cc\u6709\u4e2a\u6cdb\u578b\u95ee\u9898\uff1a`remove` \u53c2\u6570\u662f `Object` \u7c7b\u578b\uff0c\u800c\u6211\u4eec\u8981\u5b58\u5165 `List<E>`\uff0c\u6240\u4ee5\u9700\u8981\u5f3a\u5236\u7c7b\u578b\u8f6c\u6362\u3002\u5728\u5b9e\u9645\u4f7f\u7528\u4e2d\u5e94\u786e\u4fdd\u7c7b\u578b\u5b89\u5168\u3002<\/p>\n\n\n\n
\u63a5\u4e0b\u6765\u6211\u4eec\u5199\u4e00\u4e2a\u6d4b\u8bd5\u7684 `main` \u51fd\u6570\u3002\u521b\u5efa\u4e00\u4e2a `HistorySet<Integer>` \u5b9e\u4f8b\uff0c\u53ef\u4ee5\u7528 `Set<Integer>` \u591a\u6001\u5f15\u7528\uff1a<\/p>\n\n\n\n
public class Main {\n    public static void main(String[] args) {\n        Set<String> set = new HistorySet<>();\n        set.add(\"1\");\n        set.add(\"2\");\n        set.add(\"3\");\n        set.add(\"4\");\n        set.remove(\"4\");\n        set.remove(\"4\");\n        set.remove(\"5\");\n        set.remove(\"1\");\n        System.out.println(set);\n    }\n}<\/code><\/pre>\n\n\n\n
\u7136\u540e\u6211\u4eec\u6253\u5370\u8fd9\u4e2a `set`\u3002\u4f46\u6211\u4eec\u8fd8\u6ca1\u5199 `toString()` \u65b9\u6cd5\uff0c\u5df2\u7ecf\u8865\u4e0a<\/p>\n\n\n\n
\n
 [2,3] remove list : [4,1]<\/p>\n<\/blockquote>\n\n\n\n
\u8fd0\u884c\u540e\u8f93\u51fa\u663e\u793a\uff1a\u5f53\u524d\u96c6\u5408\u4e2d\u6709 2 \u548c 3\uff0c\u88ab\u5220\u9664\u7684\u5143\u7d20\u662f 4 \u548c 1\uff0c\u800c 5 \u56e0\u4e3a\u4ece\u672a\u5b58\u5728\u8fc7\uff0c\u6240\u4ee5\u6ca1\u6709\u88ab\u8bb0\u5f55\u3002<\/p>\n\n\n\n
\u6211\u4eec\u518d\u56de\u5934\u770b\u8fd9\u4e2a `HistorySet` \u7c7b\u3002\u6211\u4eec\u5b9e\u73b0\u4e86 `Set` \u63a5\u53e3\uff0c\u4f46\u6211\u4eec\u81ea\u5df1\u5e76\u6ca1\u6709\u771f\u6b63\u5b9e\u73b0\u4efb\u4f55 `Set` \u7684\u903b\u8f91\uff0c\u800c\u662f\u628a\u6240\u6709\u64cd\u4f5c\u90fd\u4ea4\u7ed9\u4e86\u5185\u90e8\u7684 `HashSet`\u3002\u8fd9\u8bf4\u660e\u6211\u4eec\u5176\u5b9e\u5e76\u4e0d\u4f9d\u8d56 `HashSet`\uff0c\u53ea\u8981\u662f `Set` \u7684\u5b9e\u73b0\u90fd\u53ef\u4ee5\u3002<\/p>\n\n\n\n
\u90a3\u5982\u679c\u6211\u4eec\u5e0c\u671b\u5e95\u5c42\u662f\u6709\u5e8f\u7684 `Set`\uff08\u6bd4\u5982 `TreeSet`\uff09\uff0c\u600e\u4e48\u529e\uff1f\u6211\u4eec\u53ef\u4ee5\u8ba9\u7528\u6237\u5728\u6784\u9020\u65f6\u4f20\u5165\u4e00\u4e2a `Set` \u5b9e\u4f8b\uff0c\u800c\u4e0d\u662f\u56fa\u5b9a\u4f7f\u7528 `HashSet`\u3002private Set<E> hashSet =new TreeSet<>();<\/p>\n\n\n\n
\u4e8e\u662f\u6211\u4eec\u4fee\u6539\u6784\u9020\u51fd\u6570\uff1a<\/p>\n\n\n\n
```java
public HistorySet(Set<E> delegate) {
    this.delegate = delegate;
}
```<\/p>\n\n\n\n
\u8fd9\u4e2a `delegate` \u5c31\u662f\u88ab\u4ee3\u7406\u7684\u5bf9\u8c61\u3002\u6211\u4eec\u5728\u521b\u5efa `HistorySet` \u65f6\u4f20\u5165\u4e00\u4e2a `HashSet` \u6216 `TreeSet` \u90fd\u53ef\u4ee5\uff1a<\/p>\n\n\n\n
public HistorySet(Set<E> hashSet) {\n    this.delegate = hashSet;\n}\n\nList<E> removeList = new ArrayList<>();\nprivate final Set<E> delegate;<\/code><\/pre>\n\n\n\n
\u8fd9\u6837\uff0c`HistorySet` \u7684\u804c\u8d23\u5c31\u975e\u5e38\u6e05\u6670\uff1a\u5b83\u53ea\u662f\u4e00\u4e2a\u201c\u5305\u88c5\u5668\u201d\uff0c\u53ea\u589e\u5f3a `remove` \u529f\u80fd\uff0c\u5176\u4f59\u6240\u6709\u884c\u4e3a\u90fd\u7531\u4ee3\u7406\u5bf9\u8c61\u5b8c\u6210\u3002<\/p>\n\n\n\n
\u8fd9\u5c31\u662f**\u88c5\u9970\u5668\u6a21\u5f0f**\u7684\u6838\u5fc3\u601d\u60f3\uff1a\u901a\u8fc7\u5305\u88c5\u4e00\u4e2a\u5bf9\u8c61\uff0c\u5728\u4e0d\u6539\u53d8\u5176\u539f\u6709\u529f\u80fd\u7684\u524d\u63d0\u4e0b\uff0c\u589e\u52a0\u65b0\u7684\u884c\u4e3a\u6216\u529f\u80fd\u3002<\/strong><\/p>\n\n\n\n
\u66f4\u8fdb\u4e00\u6b65\uff0c\u65e2\u7136 `HistorySet` \u672c\u8eab\u4e5f\u662f\u4e00\u4e2a `Set`\uff0c\u90a3\u6211\u4eec\u80fd\u4e0d\u80fd\u628a\u5b83\u518d\u5305\u88c5\u4e00\u6b21\uff1f\u6bd4\u5982\uff1a\u88c5\u9970\u7684historyset\u4f5c\u4e3aset\u8fdb\u4e00\u6b65\u653e\u5230historyset\u4e2d\uff0c\u8bb0\u5f55\u5206\u522bremove\u7684\u7cfb\u7edf\uff1b <\/p>\n\n\n\n
public class Main {\n    public static void main(String[] args) {\n        Set<String> historySet = new HistorySet<>(new HashSet<>());\n        Set<String> set = new HistorySet<>(historySet);\n        set.add(\"1\");\n        set.add(\"2\");\n        set.add(\"3\");\n        set.add(\"4\");\n        set.remove(\"4\");\n        set.remove(\"4\");\n        set.remove(\"5\");\n        set.remove(\"1\");\n        System.out.println(set);\n    }\n}<\/code><\/pre>\n\n\n\n
\u8fd9\u65f6\uff0c`doubleHistorySet` \u5185\u90e8\u5d4c\u5957\u4e86\u4e24\u4e2a `HistorySet`\u3002\u6bcf\u6b21\u6210\u529f\u5220\u9664\u4e00\u4e2a\u5143\u7d20\uff0c\u4e24\u4e2a\u5305\u88c5\u5668\u90fd\u4f1a\u8bb0\u5f55\u4e00\u6b21\u3002\u8fd0\u884c\u6d4b\u8bd5\u540e\u53ef\u4ee5\u770b\u5230\uff0c\u4e24\u4e2a `removedList` \u90fd\u8bb0\u5f55\u4e86\u76f8\u540c\u7684\u5220\u9664\u64cd\u4f5c\u3002<\/p>\n\n\n\n
\u30102,3\u3011remove list :[4,1] remove list :[4,1]<\/p>\n\n\n\n
\u8fd9\u8bf4\u660e\u88c5\u9970\u5668\u53ef\u4ee5\u5c42\u5c42\u53e0\u52a0\uff0c\u5f62\u6210\u201c\u88c5\u9970\u94fe\u201d\u3002<\/p>\n\n\n\n
\u6211\u4eec\u6765\u770b\u4e00\u4e2a JDK \u4e2d\u7684\u7ecf\u5178\u4f8b\u5b50\uff1a`Collections.synchronizedCollection(Collection<T> c)`\u3002\u5b83\u63a5\u6536\u4e00\u4e2a `Collection`\uff0c\u8fd4\u56de\u4e00\u4e2a\u7ebf\u7a0b\u5b89\u5168\u7684\u5305\u88c5\u7248\u672c\u3002<\/p>\n\n\n\n
Collection<Object> objects =Collections.synchronizedCollection(new ArrayList<>());<\/p>\n\n\n\n
\u70b9\u8fdb\u53bb\u770b\u6e90\u7801\uff0c\u5b83\u8fd4\u56de\u7684\u662f `SynchronizedCollection`\uff0c\u8fd9\u4e2a\u7c7b\u5b9e\u73b0\u4e86 `Collection`\uff0c\u5185\u90e8\u6301\u6709\u4e00\u4e2a `Collection` \u5bf9\u8c61\uff08\u79f0\u4e3a `c`\uff09\uff0c\u6240\u6709\u65b9\u6cd5\u90fd\u59d4\u6258\u7ed9 `c` \u6267\u884c\uff0c\u6bd4\u5982\uff1a<\/p>\n\n\n\n
```java
public int size() {
    synchronized (mutex) { return c.size(); }
}
public boolean isEmpty() {
    synchronized (mutex) { return c.isEmpty(); }
}
```<\/p>\n\n\n\n
\u552f\u4e00\u7684\u533a\u522b\u662f\uff0c\u6bcf\u4e2a\u65b9\u6cd5\u90fd\u52a0\u4e86 `synchronized` \u9501\uff0c\u9501\u7684\u662f\u4e00\u4e2a\u4e92\u65a5\u5bf9\u8c61 `mutex`\uff08\u901a\u5e38\u662f `this`\uff09\u3002\u8fd9\u6837\u5c31\u5b9e\u73b0\u4e86\u7ebf\u7a0b\u5b89\u5168\u3002<\/p>\n\n\n\n
\u4f46\u8981\u6ce8\u610f\uff1a\u5355\u4e2a\u65b9\u6cd5\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\uff0c\u4f46\u591a\u4e2a\u65b9\u6cd5\u7684\u7ec4\u5408\u64cd\u4f5c\u4e0d\u662f\u539f\u5b50\u7684\u3002\u6bd4\u5982\uff1a<\/p>\n\n\n\n
```java
if (collection.isEmpty()) {
    collection.add(item); \/\/ \u8fd9\u4e0d\u662f\u539f\u5b50\u64cd\u4f5c\uff01
}
```<\/p>\n\n\n\n
\u5728\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\uff0c\u8fd9\u4e2a\u5224\u65ad\u52a0\u6dfb\u52a0\u7684\u64cd\u4f5c\u4ecd\u7136\u53ef\u80fd\u51fa\u9519\uff0c\u9700\u8981\u989d\u5916\u540c\u6b65\u3002<\/p>\n\n\n\n
\u8fd9\u662f\u88c5\u9970\u5668\u6a21\u5f0f\u7684\u53c8\u4e00\u5e94\u7528\uff1a\u5728\u4e0d\u4fee\u6539\u539f\u59cb\u7c7b\u7684\u60c5\u51b5\u4e0b\uff0c\u589e\u52a0\u540c\u6b65\u63a7\u5236\u3002<\/p>\n\n\n\n
\u518d\u770b\u7b2c\u4e09\u4e2a\u4f8b\u5b50\uff1a\u6709\u4e00\u4e2a 20MB \u7684 PDF \u6587\u4ef6\uff0c\u6211\u4eec\u9700\u8981\u4e00\u4e2a\u5b57\u8282\u4e00\u4e2a\u5b57\u8282\u5730\u8bfb\u53d6\u3002\u6211\u4eec\u4f7f\u7528 `FileInputStream`\uff1a<\/p>\n\n\n\n
public class Main {\n    public static void main(String[] args) {\n        File file = new File(\"jvm.pdf\");\n        long l = Instant.now().toEpochMilli();\n        try(FileInputStream fileInputStream = new FileInputStream(file)){\n            while (true){\n                int read = fileInputStream.read();\n                if(read == -1){\n                    break;\n                }\n            }\n            System.out.println(\"\u7528\u65f6:\" + (Instant.now().toEpochMilli() - l) + \"\u6beb\u79d2\");\n        } catch (IOException e) {\n            throw new RuntimeException(e);\n        }\n    }\n}<\/code><\/pre>\n\n\n\n
\u6d4b\u8bd5\u53d1\u73b0\u8017\u65f6\u7ea6 8 \u79d2\u3002\u4e3a\u4ec0\u4e48\u8fd9\u4e48\u6162\uff1f\u56e0\u4e3a `read()` \u6bcf\u6b21\u90fd\u662f\u4e00\u6b21 I\/O \u64cd\u4f5c\uff0c\u9891\u7e41\u7684\u5c0f\u6570\u636e\u8bfb\u53d6\u6548\u7387\u6781\u4f4e\u3002<\/p>\n\n\n\n
\u6211\u4eec\u601d\u8003\uff1a\u80fd\u4e0d\u80fd\u52a0\u4e00\u4e2a\u7f13\u51b2\u533a\uff1f\u5982\u679c\u80fd\u4ece\u5185\u5b58\u7f13\u51b2\u533a\u8bfb\u6570\u636e\uff0c\u5c31\u907f\u514d\u4e86\u9891\u7e41\u7684 I\/O\u3002<\/p>\n\n\n\n
\u4e8e\u662f\u6211\u4eec\u521b\u5efa\u4e00\u4e2a\u7c7b\uff1a`BufferedFileInputStream`\uff0c\u5b83\u4e5f\u7ee7\u627f `InputStream`\uff0c\u4f46\u5185\u90e8\u5305\u88c5\u4e86\u4e00\u4e2a `FileInputStream`\uff1a\u6784\u9020\u51fd\u6570\u4f20\u9012\u4e00\u4e0b\uff1b<\/p>\n\n\n\n
public class BufferedFileInputStream extends InputStream {\n\n    private final byte[] buffer = new byte[8192];\n\n    private final FileInputStream fileInputStream;\n\n    public BufferedFileInputStream(FileInputStream fileInputStream){\n        this.fileInputStream = fileInputStream;\n    }\n\n    @Override\n    public int read() throws IOException {\n        return 0;\n    }\n\n    @Override\n    public void close() throws IOException {\n        super.close();\n    }\n}<\/code><\/pre>\n\n\n\n
\u91cd\u5199 `read()` \u65b9\u6cd5\uff1a<\/p>\n\n\n\n
@Override\npublic int read() throws IOException {\n    if(buffCanRead()){\n        return readFromBuffer();\n    }\n    refreshBuffer();\n    if(!buffCanRead()){\n        return -1;\n    }\n\n    return readFromBuffer();\n}<\/code><\/pre>\n\n\n\n
\u5176\u4e2d\uff1a<\/p>\n\n\n\n
- `canReadFromBuffer()` \u5224\u65ad\u662f\u5426\u8fd8\u80fd\u4ece\u7f13\u51b2\u533a\u8bfb\u53d6\uff1a`position < capacity`
- `refreshBuffer()` \u8c03\u7528 `fis.read(buffer)`\uff0c\u5c06\u6570\u636e\u8bfb\u5165\u7f13\u51b2\u533a\uff0c\u66f4\u65b0 `capacity` \u548c `position = 0`
- `readFromBuffer()` \u8fd4\u56de `buffer[position++] & 0xFF`\uff08\u8f6c\u4e3a\u65e0\u7b26\u53f7 int\uff09<\/p>\n\n\n\n
public class Main {\n    public static void main(String[] args) {\n        File file = new File(\"jvm.pdf\");\n        long l = Instant.now().toEpochMilli();\n        try (InputStream fileInputStream = new BufferedFileInputStream(new FileInputStream(file))) {\n            while (true) {\n                int read = fileInputStream.read();\n                if (read == -1) {\n                    break;\n                }\n            }\n            System.out.println(\"\u7528\u65f6:\" + (Instant.now().toEpochMilli() - l) + \"\u6beb\u79d2\");\n        } catch (IOException e) {\n            throw new RuntimeException(e);\n        }\n    }\n}<\/code><\/pre>\n\n\n\n
public class BufferedFileInputStream extends InputStream {\n\n    private final byte[] buffer = new byte[8192];\n\n    private int position = -1;\n\n    private int capacity = -1;\n\n    private final FileInputStream fileInputStream;\n\n    public BufferedFileInputStream(FileInputStream fileInputStream) {\n        this.fileInputStream = fileInputStream;\n    }\n\n    @Override\n    public int read() throws IOException {\n        if (buffCanRead()) {\n            return readFromBuffer();\n        }\n        refreshBuffer();\n        if (!buffCanRead()) {\n            return -1;\n        }\n        return readFromBuffer();\n    }\n\n    private int readFromBuffer() {\n        return buffer[position++] & 0xFF;\n    }\n\n    private void refreshBuffer() throws IOException {\n        capacity = this.fileInputStream.read(buffer);\n        position = 0;\n    }\n}<\/code><\/pre>\n\n\n\n
\n
\u4e3a\u4e86\u5b9e\u73b0\u8fd9\u51e0\u4e2a\u51fd\u6570\uff0c\u6211\u4eec\u5148\u601d\u8003\u4e00\u4e2a\u95ee\u9898\uff0cRead from buffer\uff0c\u6211\u4eec\u4ece\u8fd9\u4e2abuffer\u4e2d\u62ff\u5230\u4e00\u4e2a\u5b57\u8282\uff0c\u90a3\u4e48\u6211\u4eec\u5e94\u8be5\u62ff\u53d6\u54ea\u4e2a\u4f4d\u7f6e\u7684\u5b57\u8282\u5462\uff0c\u4e8e\u662f\u6211\u4eec\u53ef\u4ee5\u7528\u4e00\u4e2a\u6807\u8bb0\u4f4d\u53bb\u6807\u8bb0position\uff0c\u6700\u5f00\u59cb\u53ef\u4ee5\u662f\u96f6\uff0c\u6807\u8bb0\u7740\u6211\u4eec\u73b0\u5728\u8bfb\u5230\u4e86\u8fd9\u4e2abuffer\u7684\u4ec0\u4e48\u4f4d\u7f6e\uff0c\u90a3\u4e48\u7b2c\u4e8c\u4e2a\u95ee\u9898\uff0c\u5047\u5982\u6211\u4eec\u73b0\u5728\u6709\u4e00\u4e2a8192\u957f\u5ea6\u7684buffer\uff0c\u4f46\u662f\u6211\u4eec\u7684FileInputStream\u6574\u4e2a\u5b57\u8282\u6d41\u90fd\u6ca1\u67098192\uff0c\u90a3\u4e48\u6211\u4eec\u8fd9\u4e2abuffer\u662f\u586b\u4e0d\u6ee1\u7684\uff0c\u6240\u4ee5\u8bf4\u6211\u4eec\u4e0d\u80fd\u76f4\u63a5\u628a\u6574\u4e2abuffer\u4e00\u4e2a\u4e00\u4e2a\u5730\u8bfb\u53d6\u5b8c\u6bd5\uff0c\u90a3\u4e48\u6211\u4eec\u5e94\u8be5\u7528\u4e00\u4e2a\u5bb9\u91cfcapacity\uff0c\u6211\u4eec\u521d\u59cb\u5316\u4e5f\u662f\u96f6\uff0c\u53bb\u6807\u8bb0\u7740\u6211\u4eec\u8fd9\u4e2abuffer\u5230\u5e95\u6709\u6548\u8bfb\u53d6\u957f\u5ea6\u662f\u591a\u5c11\uff0c\u800c\u4e0d\u80fd\u662f\u4e00\u6b21\u6027\u65e0\u8111\u628a8192\u5168\u90fd\u8bfb\u5b8c\uff0c\u90a3\u4e48\u6211\u4eec\u53ef\u4ee5\u770b\u4e00\u4e0b\u8fd9\u4e2abuffer\u7684read\u65b9\u6cd5\uff0cOK\uff0c\u90a3\u4e48\u73b0\u5728\u6211\u4eec\u6765\u601d\u8003bufferCanRead\uff0c\u4ec0\u4e48\u65f6\u5019\u8fd9\u4e2abuffer\u662f\u80fd\u8bfb\u7684\u5462\uff0c\u9996\u5148\u5728\u521d\u59cb\u5316\u7684\u65f6\u5019\uff0c\u8fd9\u4e2aposition\u548ccapacity\u90fd\u662f\u96f6\uff0c\u90a3\u80af\u5b9a\u662f\u4e0d\u80fd\u8bfb\u53d6\u7684\uff0c\u6240\u4ee5\u5f53capacity\u7b49\u4e8e\u96f6\u7684\u65f6\u5019\u80af\u5b9a\u662f\u4e0d\u80fd\u8bfb\u7684\uff0c\u8fd4\u56defalse\uff0cOK\uff0c\u90a3\u5982\u679ccapacity\u4e0d\u662f\u96f6\uff0c\u5047\u5982\u8bf4\u73b0\u5728\u7684capacity\u662f8192\uff0c\u6211\u4eec\u7684\u6574\u4e2aBuffer\u662f\u586b\u6ee1\u7684\uff0c\u90a3\u4e48\u5f53position\u8d70\u5230\u4e86capacity\u7684\u65f6\u5019\uff0c\u90a3\u8bf4\u660e\u6211\u4eec\u5df2\u7ecf\u8bfb\u5230\u4e86\u6700\u540e\u4e00\u4e2a\u5b57\u8282\uff0c\u90a3\u4e48\u6211\u4eec\u4e5f\u4e0d\u80fd\u518d\u8bfb\u4e86\uff0c\u6240\u4ee5position\u7b49\u4e8ecapacity\u7684\u65f6\u5019\u4e5f\u662f\u4e0d\u80fd\u8bfb\u7684\uff0c\u4e5f\u8fd4\u56defalse\uff0c\u5426\u5219\u5c31\u8fd4\u56detrue\uff0c\u8fd4\u56detrue\u7684\u65f6\u5019\u8bf4\u660e\u4ec0\u4e48\u5462\uff0c\u8bf4\u660eposition\u5728capacity\u4e4b\u524d\uff0c\u5e76\u4e14capacity\u5927\u4e8eposition\uff0c\u8bf4\u660e\u6211\u4eec\u7684buffer\u662f\u53ef\u4ee5\u8bfb\u7684\uff0c\u597d\u7684\uff0c\u73b0\u5728\u6211\u4eec\u6765\u586b\u5145\u7b2c\u4e8c\u4e2a\u51fd\u6570\uff0crefreshBuffer\uff0c\u9996\u5148\u6211\u4eec\u8c03\u7528refreshBuffer\u7684\u65f6\u5019\uff0cbufferCanRead\u4e00\u5b9a\u662f\u8fd4\u56defalse\u7684\uff0c\u6240\u4ee5\u6211\u4eec\u53ef\u4ee5\u76f4\u63a5\u5ffd\u7565\u5f53\u524dposition\u548ccapacity\u7684\u5177\u4f53\u503c\uff0c\u6211\u4eec\u76f4\u63a5\u7528\u5185\u90e8\u7684FileInputStream\u53bb\u8bfb\u53d6\uff0c\u8bfb\u53d6\u5230\u8fd9\u4e2abuffer\u7684\u5b57\u8282\u6570\u7ec4\u4e2d\uff0c\u8fd4\u56de\u7684\u662f\u4e00\u4e2alength\uff0c\u8868\u793a\u8fd9\u6b21\u8bfb\u53d6\u771f\u6b63\u8bfb\u53d6\u4e86\u591a\u5c11\u5b57\u8282\uff0c\u90a3\u4e48\u6211\u4eec\u53ef\u4ee5\u76f4\u63a5\u7528capacity\u7b49\u4e8e\u8fd9\u4e2a\u6570\u5b57\uff0c\u5982\u679ccapacity\u7b49\u4e8e\u96f6\uff0c\u90a3\u4e48bufferCanRead\u5c31\u4f1a\u8fd4\u56defalse\uff0c\u8868\u793a\u6ca1\u6709\u53ef\u8bfb\u6570\u636e\uff0c\u5982\u679c\u5b83\u771f\u6b63\u8bfb\u53d6\u51fa\u4e86\u957f\u5ea6\uff0c\u90a3\u4e48\u8bfb\u53d6\u51fa\u6765\u662f\u591a\u5c11\uff0c\u6211\u4eec\u7684capacity\u5c31\u8bbe\u4e3a\u591a\u5c11\uff0c\u8fd9\u91cc\u6709\u4e00\u4e2aIOException\uff0c\u6211\u4eec\u76f4\u63a5\u629b\u51fa\u53bb\uff0c\u56e0\u4e3a\u6211\u4eec\u7684read\u65b9\u6cd5\u4e5f\u8981\u629b\u51fa\u8fd9\u4e2a\u5f02\u5e38\uff0c\u4ea4\u7ed9\u4e0a\u5c42\u5904\u7406\u5c31\u53ef\u4ee5\u4e86\uff0c\u5f53\u6211\u4eec\u4fee\u6539\u4e86capacity\u7684\u957f\u5ea6\u4e4b\u540e\uff0c\u6211\u4eec\u8981\u628aposition\u53d8\u6210\u96f6\uff0c\u56e0\u4e3a\u6211\u4eec\u8981\u91cd\u7f6e\u8fd9\u4e2aposition\uff0c\u8ba9\u5b83\u4ece\u96f6\u5f00\u59cb\u8bfb\u53d6\uff0c\u597d\u7684\uff0c\u73b0\u5728\u6211\u4eec\u6765\u586b\u5145\u6700\u540e\u4e00\u4e2a\u51fd\u6570\uff0creadFromBuffer\uff0c\u8fd9\u4e2a\u51fd\u6570\u5c31\u5f88\u7b80\u5355\u4e86\uff0c\u76f4\u63a5return buffer[position]\uff0c\u4f46\u662fposition\u5728\u8bfb\u53d6\u4e4b\u540e\u8981\u81ea\u589e\u4e00\uff0c\u6240\u4ee5\u662fbuffer[position++]\uff0cOK\uff0c\u8fd9\u91cc\u8fd8\u6709\u4e00\u4e2a\u7ec6\u8282\u662fbuffer\u662f\u4e00\u4e2a\u5b57\u8282\u6570\u7ec4\uff0c\u8fd9\u4e2a\u5b57\u8282\u9ed8\u8ba4\u662f\u6709\u7b26\u53f7\u7684\uff0c\u53ef\u80fd\u4e3a\u8d1f\u6570\uff0c\u4f46\u662f\u6211\u4eec\u7684\u8fd4\u56de\u503c\u8981\u6c42\u662f0~255\uff0c\u6240\u4ee5\u6211\u4eec\u8981\u4e0e\u4e0a0xFF\uff0c\u4e5f\u5c31\u662f(byte & 0xFF)\uff0c\u53bb\u6389\u7b26\u53f7\u4f4d\u7684\u5f71\u54cd\uff0c\u8ba9\u5176\u8f6c\u6362\u4e3a\u65e0\u7b26\u53f7\u6574\u6570\uff0c\u8fd9\u6837\u7684\u8bdd\uff0c\u6211\u4eec\u7684\u6574\u4e2aBufferedFileInputStream\u5c31\u5199\u5b8c\u4e86\uff0c\u5176\u5b9e\u6574\u4e2a\u6d41\u7a0b\u5f88\u7b80\u5355\uff0c\u6211\u4eec\u53ea\u662f\u5305\u88c5\u4e86\u4e00\u4e0b\u8fd9\u4e2aFileInputStream\uff0c\u7136\u540e\u5728\u5b83\u8bfb\u53d6\u7684\u65f6\u5019\uff0c\u6211\u4eec\u8fdb\u884c\u4e86\u4e00\u4e9bbuffer\u7684\u62e6\u622a\uff0c\u5982\u679cbuffer\u91cc\u9762\u53ef\u4ee5\u8bfb\u7684\u8bdd\uff0c\u6211\u4eec\u5c31\u4ecebuffer\u91cc\u9762\u8bfb\uff0c\u5982\u679cbuffer\u4e0d\u53ef\u4ee5\u8bfb\u7684\u8bdd\uff0c\u6211\u4eec\u5c31\u8c03\u7528refreshBuffer\u53bb\u586b\u5145buffer\uff0c\u8fd9\u6837\u7684\u8bdd\u6211\u4eec\u5c31\u6781\u5927\u5730\u51cf\u5c11\u4e86\u771f\u6b63\u7684IO\u64cd\u4f5c\u6b21\u6570\uff0c\u90a3\u4e48\u6211\u4eec\u6765\u8bd5\u4e00\u4e0b\uff0c\u6211\u4eec\u4fee\u6539\u4e4b\u540e\u7684\u8fd9\u4e2aBufferedFileInputStream\uff0c\u5b83\u5230\u5e95\u6709\u591a\u5feb\uff0c\u6211\u4eec\u4e4b\u524d\u7528\u4e86\u516b\u79d2\u6765\u8bfb\u53d6\u6574\u4e2a\u6587\u4ef6\uff0c\u90a3\u4e48\u6211\u4eec\u628a\u5b83\u6362\u6210BufferedFileInputStream\uff0c\u7136\u540e\u5728\u91cc\u9762\u5c01\u88c5\u4e00\u4e2aFileInputStream\uff0c\u628a\u8fd9\u4e2afile\u4f20\u8fdb\u53bb\uff0c\u6211\u4eec\u6574\u4e2a\u662f\u4e00\u4e2aInputStream\u7c7b\uff0c\u5176\u4ed6\u51fd\u6570\u4e00\u884c\u90fd\u4e0d\u7528\u53d8\u3002<\/p>\n<\/blockquote>\n\n\n\n
\u8fd9\u6837\uff0c\u6211\u4eec\u7528 `BufferedFileInputStream` \u5305\u88c5 `FileInputStream`\uff0c\u5c31\u80fd\u5927\u5e45\u63d0\u5347\u6027\u80fd\u3002\u518d\u6b21\u8fd0\u884c\u6d4b\u8bd5\uff0c\u65f6\u95f4\u4ece 8 \u79d2\u964d\u5230 46ms\uff0c\u6027\u80fd\u63d0\u5347\u4e24\u4e2a\u6570\u91cf\u7ea7\u3002<\/p>\n\n\n\n
\u6211\u4eec\u8fd8\u53ef\u4ee5\u9a8c\u8bc1\u6b63\u786e\u6027\uff1a\u540c\u65f6\u7528\u539f\u59cb `FileInputStream` \u548c\u5305\u88c5\u540e\u7684\u6d41\u8bfb\u53d6\uff0c\u5bf9\u6bd4\u6bcf\u6b21\u8bfb\u53d6\u7684\u5b57\u8282\u662f\u5426\u4e00\u81f4\u3002\u5982\u679c\u7a0b\u5e8f\u6b63\u5e38\u7ed3\u675f\uff0c\u8bf4\u660e\u6211\u4eec\u7684 `BufferedFileInputStream` \u884c\u4e3a\u6b63\u786e\u3002<\/p>\n\n\n\n
\u8fd9\u5c31\u662f\u4e3a\u4ec0\u4e48\u6211\u4eec\u8bf4 Java I\/O \u4f53\u7cfb\u662f\u88c5\u9970\u5668\u6a21\u5f0f\u7684\u7ecf\u5178\u5e94\u7528\uff1a`BufferedInputStream`\u3001`DataInputStream`\u3001`ObjectInputStream` \u7b49\u90fd\u53ef\u4ee5\u5c42\u5c42\u5305\u88c5 `InputStream`\uff0c\u6bcf\u4e2a\u88c5\u9970\u5668\u53ea\u8d1f\u8d23\u81ea\u5df1\u7684\u529f\u80fd\uff08\u7f13\u51b2\u3001\u6570\u636e\u89e3\u6790\u3001\u5bf9\u8c61\u5e8f\u5217\u5316\u7b49\uff09\uff0c\u800c\u539f\u59cb\u6d41\u53ea\u8d1f\u8d23\u8bfb\u53d6\u5b57\u8282\u3002<\/p>\n\n\n\n
\u6700\u540e\u7559\u4e00\u4e2a\u601d\u8003\u9898\uff1a\u4f60\u80fd\u5426\u5728 `InputStream` \u7684\u57fa\u7840\u4e0a\u518d\u88c5\u9970\u4e00\u5c42\uff0c\u7528\u6765\u8bb0\u5f55 `read()` \u65b9\u6cd5\u88ab\u8c03\u7528\u4e86\u591a\u5c11\u6b21\uff1f\u4e0b\u671f\u6211\u5c06\u7528\u88c5\u9970\u5668\u6a21\u5f0f\u5b9e\u6218\u4e00\u4e2a\u7efc\u5408\u6848\u4f8b\u3002<\/p>\n\n\n\n
\u5982\u679c\u4f60\u60f3\u5b9e\u73b0\u8bfb\u53d6\u884c\u6570\uff0c\u6211\u7684\u5efa\u8bae\u662f\u4e0d\u8981\u76f4\u63a5\u5728BufferedFileInputStream\u76f4\u63a5\u5199\u4ee3\u7801\u3002 \u800c\u662f\u81ea\u5df1\u518d\u5b9a\u4e49\u4e00\u4e2aCountFileInputStream \u7136\u540e\u628aBufferedFileInputStream\u4f20\u8fdb\u6765\uff0c\u8fd9\u6837\u80fd\u4f53\u73b0\u88c5\u9970\u5668\u6a21\u5f0f\u591a\u5c42\u88c5\u9970\u7684\u6548\u679c<\/p>\n\n\n\n
\u4e3a\u4ec0\u4e48\u4e0d\u76f4\u63a5\u7ee7\u627f\uff1a 1. \u88c5\u9970\u5668\u7684\u529f\u80fd\u53ef\u80fd\u4f9d\u8d56\u88ab\u88c5\u9970\u5bf9\u8c61\u7684\u7279\u6027\uff0c\u6bd4\u5982\u89c6\u9891\u4e2d\u7684\u4f8b\u5b50\uff0c\u9700\u8981\u8ba9set\u6709\u5e8f\uff0c\u90a3\u53ea\u80fd\u5305\u88c5TreeSet\uff0cHashSet\u6ee1\u8db3\u4e0d\u4e86\u9700\u6c42\u3002 2. \u5982\u679c\u88ab\u88c5\u9970\u7684\u5bf9\u8c61\u662ffinal\u5c31\u6ca1\u529e\u6cd5\u7ee7\u627f 3. Java\u53ea\u80fd\u5355\u4e00\u7ee7\u627f\uff0c\u5982\u679c\u4f60\u9700\u8981\u7ee7\u627f\u5176\u4ed6\u7c7b\u90a3\u5c31\u505a\u4e0d\u5230\u4e86\u3002 4. \u88c5\u9970\u5668\u53ef\u4ee5\u591a\u6b21\u88c5\u9970\uff0c\u5c42\u7ea7\u88c5\u9970\uff0c\u4f60\u53ef\u4ee5\u53d1\u6325\u60f3\u8c61\u529b\u5404\u79cd\u5c01\u88c5\u7ec4\u5408\uff0c\u4f46\u662f\u7ee7\u627f\u4e0d\u53ef\u4ee5\u3002 5. \u7ec4\u5408\u6c38\u8fdc\u4f18\u4e8e\u7ee7\u627f<\/strong><\/p>\n\n\n\n
\u5b9e\u6218\u90e8\u5206<\/h2>\n\n\n\n
\u8fd9\u662f\u4e00\u4e2a\u7b80\u5355\u7684 Spring Boot \u5de5\u7a0b\uff0c\u9879\u76ee\u4e2d\u53ea\u6709\u4e00\u4e2a\u4f9d\u8d56\uff1a`spring-boot-starter-web`\uff0c\u7248\u672c\u662f 3.4.1\u3002\u5de5\u7a0b\u91cc\u6709\u4e00\u4e2a\u542f\u52a8\u7c7b\u3001\u4e00\u4e2a\u7b80\u5355\u7684 Controller\uff0cController \u4e2d\u53ea\u6709\u4e00\u4e2a POST \u8bf7\u6c42\u63a5\u53e3\uff0c\u63a5\u6536\u8bf7\u6c42\u4f53\uff08request body\uff09\u7684 JSON \u6570\u636e\uff0c\u5e76\u539f\u6837\u8fd4\u56de\u3002<\/p>\n\n\n\n
\u4ee3\u7801\u975e\u5e38\u7b80\u5355\uff1a<\/p>\n\n\n\n
\/**\n * @author gongxuanzhangmelt@gmail.com\n **\/\n@RestController\n@RequestMapping(\"\/api\")\npublic class MyController {\n\n    @PostMapping\n    public Map<String, Object> origin(@RequestBody Map<String, Object> json) {\n        return json;\n    }\n}<\/code><\/pre>\n\n\n\n
<\/p>\n\n\n\n
@SpringBootApplication\npublic class Application {\n\n    public static void main(String[] args) {\n        SpringApplication.run(Application.class);\n    }\n}<\/code><\/pre>\n\n\n\n
\u6211\u4eec\u542f\u52a8\u9879\u76ee\uff0c\u7528\u5de5\u5177\u53d1\u9001\u4e00\u4e2a\u8bf7\u6c42\uff0c\u4f20\u5165 `{\"name\": \"tom\", \"age\": 12}`\uff0c\u8fd4\u56de\u7ed3\u679c\u4e5f\u662f `{\"name\": \"tom\", \"age\": 12}`\uff0c\u529f\u80fd\u6b63\u5e38\u3002<\/p>\n\n\n\n
\u73b0\u5728\u6211\u4eec\u6709\u4e00\u4e2a\u65b0\u9700\u6c42\uff1a\u5e0c\u671b\u5728\u4e0d\u4fee\u6539\u539f\u6709\u903b\u8f91\u7684\u524d\u63d0\u4e0b\uff0c**\u81ea\u52a8\u4e3a\u6240\u6709\u901a\u8fc7 `@RequestBody` \u63a5\u6536\u7684 Map \u7c7b\u578b\u6570\u636e\u6dfb\u52a0\u4e00\u4e2a\u65f6\u95f4\u6233\u5b57\u6bb5**\uff0c\u6bd4\u5982\u8fd4\u56de\u7ed3\u679c\u81ea\u52a8\u53d8\u6210\uff1a<\/p>\n\n\n\n
```json
{
  \"name\": \"tom\",
  \"age\": 12,
  \"timestamp\": 1712345678901
}
```<\/p>\n\n\n\n
\u4e5f\u5c31\u662f\u8bf4\uff0c\u6211\u4eec\u60f3\u901a\u8fc7\u4e00\u4e2a\u81ea\u5b9a\u4e49\u6ce8\u89e3\uff0c\u6bd4\u5982 `@TimestampRequestBody`\uff0c\u6765\u5b9e\u73b0\u8fd9\u4e2a\u529f\u80fd\u3002\u4f46\u8fd9\u4e00\u6b21\uff0c\u6211\u4eec\u4e0d\u76f4\u63a5\u67e5\u6587\u6863\u6216\u95ee AI\uff0c\u800c\u662f\u901a\u8fc7**\u6253\u65ad\u70b9\u3001\u8bfb\u6e90\u7801\u3001\u4e00\u6b65\u6b65\u8c03\u8bd5**\u7684\u65b9\u5f0f\u6765\u5b9e\u73b0\u3002<\/p>\n\n\n\n
\u6211\u4eec\u5148\u5728 `test` \u65b9\u6cd5\u7684\u53c2\u6570 `data` \u4e0a\u6253\u4e00\u4e2a\u65ad\u70b9\uff0c\u770b\u770b\u8fd9\u4e2a `Map` \u662f\u4ec0\u4e48\u65f6\u5019\u521b\u5efa\u7684\u3002\u8fdb\u5165\u8c03\u8bd5\u540e\uff0c\u8c03\u7528\u6808\u663e\u793a\u524d\u9762\u6709\u5f88\u591a\u53cd\u5c04\u76f8\u5173\u7684\u8c03\u7528\u3002\u6211\u4eec\u4ece\u6700\u5f00\u59cb\u7684\u65b9\u6cd5\u770b\u8d77\uff1a<\/p>\n\n\n\n
\u5f53\u524d\u65b9\u6cd5\u7684\u53c2\u6570 `data` \u662f\u4e00\u4e2a `LinkedHashMap`\uff0c\u5185\u5bb9\u5c31\u662f\u6211\u4eec\u4f20\u5165\u7684 JSON\u3002\u6211\u4eec\u5411\u4e0a\u67e5\u770b\u8fd9\u4e2a\u53c2\u6570\u503c\u662f\u4ece\u54ea\u91cc\u6765\u7684\uff0c\u53d1\u73b0\u5b83\u6765\u81ea `getMethodArgumentValues()` \u65b9\u6cd5\u3002<\/p>\n\n\n\n
\u8fdb\u5165\u8be5\u65b9\u6cd5\uff0c\u5b83\u4f1a\u6839\u636e Controller \u65b9\u6cd5\u7684\u53c2\u6570\u4e2a\u6570\u521b\u5efa\u4e00\u4e2a `args Object[]` \u6570\u7ec4\uff0c\u7528\u4e8e\u5b58\u653e\u6bcf\u4e2a\u53c2\u6570\u7684\u503c\u3002\u6211\u4eec\u7684\u65b9\u6cd5\u53ea\u6709\u4e00\u4e2a\u53c2\u6570\uff0c\u6240\u4ee5\u6570\u7ec4\u957f\u5ea6\u4e3a 1\u3002<\/p>\n\n\n\n
\u63a5\u4e0b\u6765\u5173\u952e\u903b\u8f91\u662f\uff1a\u904d\u5386\u6240\u6709 `HandlerMethodArgumentResolver`\uff08\u5904\u7406\u5668\u65b9\u6cd5\u53c2\u6570\u89e3\u6790\u5668\uff09\uff0c\u5224\u65ad\u54ea\u4e00\u4e2a\u652f\u6301\u5f53\u524d\u53c2\u6570\uff0c\u7136\u540e\u8c03\u7528\u5176 `resolveArgument()` \u65b9\u6cd5\u6765\u89e3\u6790\u5e76\u8fd4\u56de\u53c2\u6570\u503c\u3002\"\"<\/p>\n\n\n\n
\u6211\u4eec\u7ee7\u7eed\u8c03\u8bd5\uff0c\u53d1\u73b0\u6700\u7ec8\u662f\u67d0\u4e2a `HandlerMethodArgumentResolver` \u7684 `resolveArgument` \u65b9\u6cd5\u8fd4\u56de\u4e86\u90a3\u4e2a `LinkedHashMap`\u3002\u6211\u4eec\u67e5\u770b\u8fd9\u4e2a\u89e3\u6790\u5668\u7684\u7c7b\u578b\uff0c\u53d1\u73b0\u662f `RequestResponseBodyMethodProcessor`\u3002<\/p>\n\n\n\n
\u6211\u4eec\u70b9\u8fdb\u53bb\u770b\u8fd9\u4e2a\u7c7b\uff0c\u5b83\u5b9e\u73b0\u4e86 `HandlerMethodArgumentResolver` \u63a5\u53e3\uff0c\u8be5\u63a5\u53e3\u6709\u4e24\u4e2a\u65b9\u6cd5\uff1a<\/p>\n\n\n\n
- `supportsParameter(MethodParameter parameter)`\uff1a\u5224\u65ad\u662f\u5426\u652f\u6301\u8be5\u53c2\u6570\uff1b
- `resolveArgument(...)`\uff1a\u771f\u6b63\u89e3\u6790\u53c2\u6570\u5e76\u8fd4\u56de\u503c\u3002<\/p>\n\n\n\n
\u6211\u4eec\u770b `supportsParameter` \u7684\u5b9e\u73b0\uff0c\u53ea\u6709\u4e00\u884c\u4ee3\u7801\uff1a\u5224\u65ad\u53c2\u6570\u662f\u5426\u6807\u6ce8\u4e86 `@RequestBody` \u6ce8\u89e3\u3002\u6240\u4ee5\u53ea\u8981\u53c2\u6570\u52a0\u4e86 `@RequestBody`\uff0cSpring \u5c31\u4f1a\u9009\u62e9\u8fd9\u4e2a\u89e3\u6790\u5668\u6765\u5904\u7406\u3002<\/p>\n\n\n\n
\u800c `resolveArgument` \u65b9\u6cd5\uff0c\u6b63\u662f**\u771f\u6b63\u5c06 JSON \u53cd\u5e8f\u5217\u5316\u4e3a Map \u7684\u5730\u65b9**\u3002\u6211\u4eec\u4e0d\u9700\u8981\u5173\u5fc3\u5b83\u5185\u90e8\u5982\u4f55\u7528 Jackson \u89e3\u6790\uff0c\u6211\u4eec\u53ea\u5173\u5fc3\uff1a\u5b83\u8fd4\u56de\u4e86\u6211\u4eec\u60f3\u8981\u7684 `Map`\u3002<\/p>\n\n\n\n
---<\/p>\n\n\n\n
\u73b0\u5728\u6211\u4eec\u60f3\uff1a\u80fd\u4e0d\u80fd\u201c\u88c5\u9970\u201d\u8fd9\u4e2a `RequestResponseBodyMethodProcessor`\uff1f\u8ba9\u5b83\u5148\u5b8c\u6210\u539f\u672c\u7684\u89e3\u6790\u529f\u80fd\uff0c\u7136\u540e\u6211\u4eec\u518d\u5bf9\u7ed3\u679c\u8fdb\u884c\u589e\u5f3a\u2014\u2014\u6bd4\u5982\u5f80 Map \u91cc put \u4e00\u4e2a\u65f6\u95f4\u6233\u3002<\/p>\n\n\n\n
\u8fd9\u5c31\u662f**\u88c5\u9970\u5668\u6a21\u5f0f**\u7684\u601d\u60f3\uff1a\u4e0d\u6539\u53d8\u539f\u6709\u903b\u8f91\uff0c\u53ea\u5728\u539f\u6709\u529f\u80fd\u57fa\u7840\u4e0a\u589e\u5f3a\u3002<\/p>\n\n\n\n
\u6211\u4eec\u65b0\u5efa\u4e00\u4e2a\u7c7b\uff1a`TimestampRequestBodyMethodProcessor`\uff0c\u4e5f\u5b9e\u73b0 `HandlerMethodArgumentResolver` \u63a5\u53e3\u3002<\/p>\n\n\n\n
\"\"<\/p>\n\n\n\n
\u6211\u4eec\u518d\u5b9a\u4e49\u4e00\u4e2a\u81ea\u5b9a\u4e49\u6ce8\u89e3\uff1a`@TimestampRequestBody`\uff0c\u4eff\u7167 `@RequestBody` \u7684\u5199\u6cd5\uff1a<\/p>\n\n\n\n
```java
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface TimestampRequestBody {}
```<\/p>\n\n\n\n
\u7136\u540e\u5728 `TimestampRequestBodyMethodProcessor` \u4e2d\uff1a<\/p>\n\n\n\n
```java
@Override
public boolean supportsParameter(MethodParameter parameter) {
    return parameter.hasParameterAnnotation(TimestampRequestBody.class);
}
```<\/p>\n\n\n\n
\u63a5\u4e0b\u6765\u662f `resolveArgument` \u65b9\u6cd5\u7684\u5b9e\u73b0\u3002\u6211\u4eec\u60f3\uff1a\u5982\u679c\u6211\u80fd\u62ff\u5230\u90a3\u4e2a\u539f\u59cb\u7684 `RequestResponseBodyMethodProcessor`\uff0c\u8ba9\u5b83\u5148\u89e3\u6790\u51fa Map\uff0c\u7136\u540e\u6211\u518d\u5f80\u91cc\u9762\u52a0\u65f6\u95f4\u6233\uff0c\u5c31\u5b8c\u6210\u4e86\u3002<\/p>\n\n\n\n
\u6240\u4ee5\u6211\u4eec\u9700\u8981\u4e00\u4e2a\u6210\u5458\u53d8\u91cf\uff0c\u6301\u6709\u88ab\u88c5\u9970\u7684 `RequestResponseBodyMethodProcessor`\uff1a<\/p>\n\n\n\n
```java
private final RequestResponseBodyMethodProcessor delegate;<\/p>\n\n\n\n
@Override
public Object resolveArgument(...) throws Exception {
    Object result = delegate.resolveArgument(parameter, mavContainer, webRequest, binderFactory);
    
    if (result instanceof Map) {
        ((Map<String, Object>) result).put(\"timestamp\", System.currentTimeMillis());
    }
    
    return result;
}
```<\/p>\n\n\n\n
\u8fd9\u6837\uff0c\u6211\u4eec\u5c31\u5b9e\u73b0\u4e86\u529f\u80fd\u589e\u5f3a\uff0c\u800c\u4e0d\u9700\u8981\u77e5\u9053\u539f\u59cb\u89e3\u6790\u5668\u5185\u90e8\u5982\u4f55\u5de5\u4f5c\u3002<\/p>\n\n\n\n
---<\/p>\n\n\n\n
\u4f46\u95ee\u9898\u6765\u4e86\uff1a\u6211\u4eec\u6709\u4e24\u4e2a\u95ee\u9898\u8981\u89e3\u51b3\uff1a<\/p>\n\n\n\n
1. \u5982\u4f55\u62ff\u5230\u90a3\u4e2a `RequestResponseBodyMethodProcessor`\uff1f
2. \u5982\u4f55\u628a\u6211\u4eec\u81ea\u5df1\u7684 `TimestampRequestBodyMethodProcessor` \u6ce8\u518c\u5230 Spring \u7684\u53c2\u6570\u89e3\u6790\u5668\u5217\u8868\u4e2d\uff1f<\/p>\n\n\n\n
---<\/p>\n\n\n\n
\u5148\u89e3\u51b3\u7b2c\u4e8c\u4e2a\u95ee\u9898\uff1a\u6ce8\u518c\u81ea\u5b9a\u4e49\u53c2\u6570\u89e3\u6790\u5668\u3002<\/p>\n\n\n\n
\u6211\u4eec\u56de\u5230\u8c03\u8bd5\uff0c\u67e5\u770b `HandlerMethodArgumentResolverComposite`\uff08\u53c2\u6570\u89e3\u6790\u5668\u7ec4\u5408\u7c7b\uff09\u7684\u5185\u90e8\uff0c\u53d1\u73b0\u5b83\u6301\u6709\u4e00\u4e2a `List<HandlerMethodArgumentResolver>`\uff0c\u91cc\u9762\u5171\u6709 27 \u4e2a\u89e3\u6790\u5668\u3002\u6211\u4eec\u627e\u5230 `RequestResponseBodyMethodProcessor` \u5728\u7b2c 8 \u4e2a\u4f4d\u7f6e\u3002<\/p>\n\n\n\n
\u8fd9\u4e2a\u5217\u8868\u662f\u600e\u4e48\u6765\u7684\uff1f\u6211\u4eec\u7ee7\u7eed\u5411\u4e0a\u770b\uff0c\u53d1\u73b0\u662f\u5728 `RequestMappingHandlerAdapter` \u4e2d\u901a\u8fc7 `getDefaultArgumentResolvers()` \u521b\u5efa\u7684\u3002<\/p>\n\n\n\n
\u6211\u4eec\u70b9\u8fdb\u53bb\uff0c\u53d1\u73b0\u662f\u4e00\u5927\u6bb5\u201c\u5c4e\u5c71\u4ee3\u7801\u201d\uff1aSpring \u786c\u7f16\u7801 new \u51fa\u4e86\u6240\u6709\u9ed8\u8ba4\u7684\u89e3\u6790\u5668\uff0c\u5e76\u653e\u5165\u5217\u8868\u3002<\/p>\n\n\n\n
\u4f46\u6ce8\u610f\u5230\u5176\u4e2d\u6709\u4e00\u6bb5\uff1a<\/p>\n\n\n\n
```java
addCustomResolvers(customArgumentResolvers);
```<\/p>\n\n\n\n
\u8fd9\u8bf4\u660e Spring \u63d0\u4f9b\u4e86\u6269\u5c55\u70b9\uff1a\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u914d\u7f6e\uff0c\u5c06\u81ea\u5b9a\u4e49\u7684\u89e3\u6790\u5668\u6dfb\u52a0\u8fdb\u53bb\u3002<\/p>\n\n\n\n
\u6211\u4eec\u7ee7\u7eed\u8c03\u8bd5\uff0c\u53d1\u73b0 `customArgumentResolvers` \u6765\u81ea `WebMvcConfigurationSupport` \u7c7b\u4e2d\u7684\u4e00\u4e2a\u65b9\u6cd5\uff1a`addArgumentResolvers()`\u3002<\/p>\n\n\n\n
\u800c\u8fd9\u4e2a\u65b9\u6cd5\u662f\u4e00\u4e2a\u7a7a\u65b9\u6cd5\uff0c\u8bf4\u660e\u5b83\u662f**\u7559\u7ed9\u7528\u6237\u91cd\u5199\u7684\u94a9\u5b50\u65b9\u6cd5**\u3002<\/p>\n\n\n\n
\u518d\u770b `WebMvcConfigurationSupport` \u7684\u5b50\u7c7b\uff0c\u53d1\u73b0\u53ea\u6709\u4e00\u4e2a\uff1a`DelegatingWebMvcConfiguration`\uff0c\u5b83\u4f1a\u6536\u96c6\u6240\u6709\u5b9e\u73b0\u4e86 `WebMvcConfigurer` \u63a5\u53e3\u7684 bean\uff0c\u5e76\u8c03\u7528\u5b83\u4eec\u7684 `addArgumentResolvers` \u65b9\u6cd5\u3002<\/p>\n\n\n\n
\u6240\u4ee5\uff0c\u6211\u4eec\u53ea\u9700\u8981\uff1a<\/p>\n\n\n\n
1. \u521b\u5efa\u4e00\u4e2a\u914d\u7f6e\u7c7b\uff0c\u5b9e\u73b0 `WebMvcConfigurer`\uff1b
2. \u91cd\u5199 `addArgumentResolvers` \u65b9\u6cd5\uff0c\u628a\u6211\u4eec\u7684 `TimestampRequestBodyMethodProcessor` \u52a0\u8fdb\u53bb\u3002<\/p>\n\n\n\n
\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n\n\n\n
```java
@Configuration
public class MyWebMvcConfig implements WebMvcConfigurer {<\/p>\n\n\n\n
    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {
        resolvers.add(new TimestampRequestBodyMethodProcessor(\/* \u9700\u8981\u4f20\u5165 delegate *\/));
    }
}
```<\/p>\n\n\n\n
\u8fd9\u6837\uff0c\u6211\u4eec\u7684\u89e3\u6790\u5668\u5c31\u4f1a\u88ab\u52a0\u5165\u5230 Spring \u7684\u89e3\u6790\u5668\u5217\u8868\u4e2d\uff0c\u5171 28 \u4e2a\u3002<\/p>\n\n\n\n
---<\/p>\n\n\n\n
\u73b0\u5728\u89e3\u51b3\u7b2c\u4e00\u4e2a\u95ee\u9898\uff1a\u5982\u4f55\u62ff\u5230 `RequestResponseBodyMethodProcessor`\uff1f<\/p>\n\n\n\n
\u6211\u4eec\u4e0d\u80fd\u7528 `@Autowired` \u76f4\u63a5\u6ce8\u5165\uff0c\u56e0\u4e3a\u5b83\u4e0d\u662f Spring \u7ba1\u7406\u7684 Bean\u2014\u2014\u5b83\u662f\u76f4\u63a5 `new` \u51fa\u6765\u7684\u3002<\/p>\n\n\n\n
\u4f46\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7 `RequestMappingHandlerAdapter` \u62ff\u5230\u5b83\u3002\u8fd9\u4e2a `adapter` \u662f Spring \u7ba1\u7406\u7684 Bean\uff0c\u5b83\u5185\u90e8\u6301\u6709\u6240\u6709\u53c2\u6570\u89e3\u6790\u5668\u3002<\/p>\n\n\n\n
\u6240\u4ee5\u6211\u4eec\u53ef\u4ee5\u5728\u914d\u7f6e\u7c7b\u4e2d\u6ce8\u5165 `ApplicationContext`\uff0c\u7136\u540e\u5728 `addArgumentResolvers` \u4e2d\u83b7\u53d6 `RequestMappingHandlerAdapter`\uff0c\u904d\u5386\u5176 `argumentResolvers`\uff0c\u627e\u5230 `RequestResponseBodyMethodProcessor`\uff0c\u4f5c\u4e3a delegate \u4f20\u5165\u3002<\/p>\n\n\n\n
\u4f46\u8981\u6ce8\u610f\uff1a\u6b64\u65f6 `RequestMappingHandlerAdapter` \u53ef\u80fd\u8fd8\u672a\u521d\u59cb\u5316\uff0c\u76f4\u63a5\u83b7\u53d6\u4f1a\u6709\u5faa\u73af\u4f9d\u8d56\u3002<\/p>\n\n\n\n
\u89e3\u51b3\u65b9\u6848\uff1a**\u5ef6\u8fdf\u521d\u59cb\u5316**\u3002\u6211\u4eec\u4e0d\u5728\u6784\u9020\u51fd\u6570\u4e2d\u8d4b\u503c\uff0c\u800c\u5728 `resolveArgument` \u7b2c\u4e00\u6b21\u8c03\u7528\u65f6\u518d\u53bb\u5bb9\u5668\u4e2d\u67e5\u627e\u5e76\u8bbe\u7f6e delegate\u3002<\/p>\n\n\n\n
\u6211\u4eec\u4fee\u6539 `TimestampRequestBodyMethodProcessor`\uff1a<\/p>\n\n\n\n
```java
private RequestResponseBodyMethodProcessor delegate;<\/p>\n\n\n\n
public void setDelegate(RequestResponseBodyMethodProcessor delegate) {
    this.delegate = delegate;
}<\/p>\n\n\n\n
private void initDelegate(ApplicationContext context) {
    if (delegate != null) return;
    
    RequestMappingHandlerAdapter adapter = context.getBean(RequestMappingHandlerAdapter.class);
    for (HandlerMethodArgumentResolver resolver : adapter.getArgumentResolvers()) {
        if (resolver instanceof RequestResponseBodyMethodProcessor) {
            this.delegate = (RequestResponseBodyMethodProcessor) resolver;
            return;
        }
    }
}
```<\/p>\n\n\n\n
\u7136\u540e\u5728 `resolveArgument` \u5f00\u5934\u8c03\u7528 `initDelegate`\u3002<\/p>\n\n\n\n
---<\/p>\n\n\n\n
\u6700\u540e\uff0c\u6211\u4eec\u5728 Controller \u4e2d\u4f7f\u7528\u6211\u4eec\u7684\u6ce8\u89e3\uff1a<\/p>\n\n\n\n
```java
@PostMapping(\"\/test\")
public Map<String, Object> test(@TimestampRequestBody Map<String, Object> data) {
    return data;
}
```<\/p>\n\n\n\n
\u91cd\u542f\u5e94\u7528\uff0c\u53d1\u9001\u8bf7\u6c42\uff0c\u8fd4\u56de\u7ed3\u679c\u6210\u529f\u5305\u542b `timestamp` \u5b57\u6bb5\u3002<\/p>\n\n\n\n
---<\/p>\n\n\n\n
\u6211\u4eec\u56de\u987e\u6574\u4e2a\u8fc7\u7a0b\uff1a<\/p>\n\n\n\n
- \u6211\u4eec\u901a\u8fc7\u8c03\u8bd5\uff0c\u627e\u5230\u4e86 `@RequestBody` \u7684\u89e3\u6790\u5668\u662f `RequestResponseBodyMethodProcessor`\uff1b
- \u6211\u4eec\u7528\u88c5\u9970\u5668\u6a21\u5f0f\u5305\u88c5\u5b83\uff0c\u589e\u5f3a\u5176\u529f\u80fd\uff1b
- \u6211\u4eec\u901a\u8fc7\u5b9e\u73b0 `WebMvcConfigurer`\uff0c\u5c06\u81ea\u5b9a\u4e49\u89e3\u6790\u5668\u6ce8\u518c\u5230 Spring \u4e2d\uff1b
- \u6211\u4eec\u901a\u8fc7 `ApplicationContext` \u5ef6\u8fdf\u83b7\u53d6\u88ab\u88c5\u9970\u7684\u5bf9\u8c61\uff0c\u907f\u514d\u4e86\u4f9d\u8d56\u95ee\u9898\u3002<\/p>\n\n\n\n
\u6574\u4e2a\u8fc7\u7a0b\u6ca1\u6709\u4fee\u6539\u4efb\u4f55 Spring \u5185\u90e8\u4ee3\u7801\uff0c\u5b8c\u5168\u57fa\u4e8e\u6269\u5c55\u673a\u5236\u5b9e\u73b0\u3002<\/p>\n\n\n\n
---<\/p>\n\n\n\n
\u601d\u8003\u9898\uff1a  
`WebMvcConfigurerComposite` \u548c `HandlerMethodArgumentResolverComposite` \u90fd\u662f\u201c\u7ec4\u5408\u6a21\u5f0f\u201d\u7684\u4f53\u73b0\uff0c\u5b83\u4eec\u6709\u4ec0\u4e48\u4e0d\u540c\uff1f  
\u524d\u8005\u662f\u5c06\u591a\u4e2a `WebMvcConfigurer` \u7684\u914d\u7f6e\u65b9\u6cd5\u5408\u5e76\u6267\u884c\uff0c\u540e\u8005\u662f\u5c06\u591a\u4e2a `ArgumentResolver` \u7ec4\u5408\u6210\u4e00\u4e2a\u89e3\u6790\u94fe\u3002\u5b83\u4eec\u7684\u804c\u8d23\u4e0d\u540c\uff1a\u4e00\u4e2a\u662f\u914d\u7f6e\u805a\u5408\uff0c\u4e00\u4e2a\u662f\u6267\u884c\u94fe\u8def\u3002<\/p>\n\n\n\n
\"\"\"\"\"\"\"\"<\/p>\n","protected":false},"excerpt":{"rendered":"
 \u88c5\u9970\u5668\u6a21\u5f0f\uff0c\u6700\u5e38\u7528\u7684\u8bbe\u8ba1\u6a21\u5f0f\u4e4b\u4e00 \u8fd9\u662f\u4e00\u4e2a\u65b0\u7684\u5de5\u7a0b\u3002\u6211\u4eec\u6709\u4e00\u4e2a\u7c7b\u53eb\u505a `HistorySet`\uff0c\u5b83\u5e26\u6709\u4e00\u4e2a\u6cdb\u578b\u53c2\u6570\uff0c\u8868 …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"emotion":"","emotion_color":"","title_style":"","license":"","footnotes":""},"categories":[2],"tags":[35],"class_list":["post-1238","post","type-post","status-publish","format-standard","hentry","category-2","tag-35"],"_links":{"self":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts\/1238","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1238"}],"version-history":[{"count":1,"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts\/1238\/revisions"}],"predecessor-version":[{"id":1239,"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts\/1238\/revisions\/1239"}],"wp:attachment":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1238"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1238"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1238"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}