{"id":2242,"date":"2025-03-02T11:21:13","date_gmt":"2025-03-02T03:21:13","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2242"},"modified":"2025-03-02T11:21:13","modified_gmt":"2025-03-02T03:21:13","slug":"java-%e5%8f%8d%e5%b0%84-reflection","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/03\/02\/java-%e5%8f%8d%e5%b0%84-reflection\/","title":{"rendered":"Java \u53cd\u5c04 (Reflection)"},"content":{"rendered":"\n

Java \u53cd\u5c04<\/strong>\u662f Java \u63d0\u4f9b\u7684\u4e00\u79cd\u5f3a\u5927\u529f\u80fd\uff0c\u5b83\u5141\u8bb8\u7a0b\u5e8f\u5728\u8fd0\u884c\u65f6\u68c0\u67e5\u548c\u64cd\u4f5c\u7c7b\u3001\u65b9\u6cd5\u3001\u6784\u9020\u51fd\u6570\u3001\u5b57\u6bb5\u7b49\u7684\u5c5e\u6027\uff0c\u800c\u4e0d\u9700\u8981\u63d0\u524d\u77e5\u9053\u5b83\u4eec\u7684\u540d\u79f0\u548c\u7ed3\u6784\u3002\u53cd\u5c04\u673a\u5236\u4f7f\u5f97 Java \u7a0b\u5e8f\u5177\u6709\u66f4\u9ad8\u7684\u7075\u6d3b\u6027\u548c\u52a8\u6001\u6027\uff0c\u901a\u5e38\u7528\u4e8e\u6846\u67b6\u5f00\u53d1\u3001\u63d2\u4ef6\u673a\u5236\u3001\u4f9d\u8d56\u6ce8\u5165\u7b49\u573a\u666f\u3002<\/p>\n\n\n\n

1. \u53cd\u5c04\u7684\u57fa\u672c\u6982\u5ff5<\/strong><\/h3>\n\n\n\n

\u53cd\u5c04\u662f\u6307\u7a0b\u5e8f\u5728\u8fd0\u884c\u65f6\u80fd\u591f\u67e5\u8be2\u548c\u64cd\u4f5c\u5bf9\u8c61\u7684\u5c5e\u6027\u3001\u65b9\u6cd5\u3001\u6784\u9020\u51fd\u6570\u7b49\u3002\u5b83\u63d0\u4f9b\u4e86\u4e00\u79cd\u901a\u8fc7\u5bf9\u8c61\u83b7\u53d6\u7c7b\u4fe1\u606f\u3001\u64cd\u4f5c\u7c7b\u5b9e\u4f8b\u7684\u65b9\u5f0f\uff0c\u800c\u4e0d\u9700\u8981\u5728\u7f16\u8bd1\u65f6\u660e\u786e\u77e5\u9053\u7c7b\u7684\u4fe1\u606f\u3002<\/p>\n\n\n\n

\u901a\u8fc7\u53cd\u5c04\uff0c\u7a0b\u5e8f\u53ef\u4ee5\uff1a<\/p>\n\n\n\n

    \n
  • \u83b7\u53d6\u7c7b\u7684\u7ed3\u6784\u4fe1\u606f<\/strong>\uff08\u7c7b\u7684\u5b57\u6bb5\u3001\u65b9\u6cd5\u3001\u6784\u9020\u65b9\u6cd5\u7b49\uff09\u3002<\/li>\n\n\n\n
  • \u52a8\u6001\u8c03\u7528\u65b9\u6cd5<\/strong>\uff0c\u65e0\u9700\u63d0\u524d\u77e5\u9053\u65b9\u6cd5\u7b7e\u540d\u3002<\/li>\n\n\n\n
  • \u8bbf\u95ee\u6216\u4fee\u6539\u5bf9\u8c61\u7684\u5b57\u6bb5<\/strong>\uff0c\u751a\u81f3\u662f\u79c1\u6709\u5b57\u6bb5\u3002<\/li>\n\n\n\n
  • \u521b\u5efa\u5bf9\u8c61\u5b9e\u4f8b<\/strong>\u3002<\/li>\n<\/ul>\n\n\n\n

    2. \u53cd\u5c04\u7684\u5173\u952e\u7c7b<\/strong><\/h3>\n\n\n\n

    \u53cd\u5c04\u7684\u529f\u80fd\u901a\u8fc7 java.lang.reflect<\/code> \u5305\u4e2d\u7684\u7c7b\u548c\u63a5\u53e3\u5b9e\u73b0\u3002\u6700\u5e38\u7528\u7684\u7c7b\u6709\uff1a<\/p>\n\n\n\n

      \n
    • Class \u7c7b<\/strong>\uff1a\u7528\u6765\u83b7\u53d6\u7c7b\u7684\u7ed3\u6784\u4fe1\u606f\u3002<\/li>\n\n\n\n
    • Field \u7c7b<\/strong>\uff1a\u7528\u6765\u64cd\u4f5c\u7c7b\u7684\u5b57\u6bb5\u3002<\/li>\n\n\n\n
    • Method \u7c7b<\/strong>\uff1a\u7528\u6765\u64cd\u4f5c\u7c7b\u7684\u65b9\u6cd5\u3002<\/li>\n\n\n\n
    • Constructor \u7c7b<\/strong>\uff1a\u7528\u6765\u64cd\u4f5c\u7c7b\u7684\u6784\u9020\u65b9\u6cd5\u3002<\/li>\n<\/ul>\n\n\n\n

      3. \u83b7\u53d6 Class \u5bf9\u8c61<\/strong><\/h3>\n\n\n\n

      Java \u4e2d\u7684\u6bcf\u4e2a\u7c7b\u90fd\u6709\u4e00\u4e2a\u5bf9\u5e94\u7684 Class<\/code> \u5bf9\u8c61\u3002\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u51e0\u79cd\u65b9\u5f0f\u6765\u83b7\u53d6\u8be5\u5bf9\u8c61\uff1a<\/p>\n\n\n\n

        \n
      • \u901a\u8fc7\u7c7b\u7684\u5b9e\u4f8b\u8c03\u7528 getClass()<\/code> \u65b9\u6cd5<\/strong>\uff1a<\/li>\n<\/ul>\n\n\n\n
          String str = \"Hello\";\n  Class<?> cls = str.getClass();<\/code><\/pre>\n\n\n\n
          \n
        • \u901a\u8fc7 Class.forName()<\/code> \u65b9\u6cd5\u83b7\u53d6<\/strong>\uff1a<\/li>\n<\/ul>\n\n\n\n
            Class<?> cls = Class.forName(\"java.lang.String\");<\/code><\/pre>\n\n\n\n
            \n
          • \u901a\u8fc7\u7c7b\u540d\u76f4\u63a5\u83b7\u53d6<\/strong>\uff1a<\/li>\n<\/ul>\n\n\n\n
              Class<?> cls = String.class;<\/code><\/pre>\n\n\n\n
            4. \u53cd\u5c04\u64cd\u4f5c\u7c7b\u7684\u4fe1\u606f<\/strong><\/h3>\n\n\n\n
            \u53cd\u5c04\u53ef\u4ee5\u5e2e\u52a9\u4f60\u5728\u8fd0\u884c\u65f6\u83b7\u5f97\u7c7b\u7684\u8be6\u7ec6\u4fe1\u606f\uff0c\u5982\u5b57\u6bb5\u3001\u65b9\u6cd5\u3001\u6784\u9020\u5668\u7b49\u3002<\/p>\n\n\n\n
            4.1 \u83b7\u53d6\u7c7b\u7684\u5b57\u6bb5<\/strong><\/h4>\n\n\n\n
            \u4f7f\u7528 Class<\/code> \u7c7b\u7684 getDeclaredFields()<\/code> \u6216 getFields()<\/code> \u65b9\u6cd5\u6765\u83b7\u53d6\u7c7b\u7684\u5b57\u6bb5\u3002<\/p>\n\n\n\n
              \n
            • getDeclaredFields()<\/code> \u8fd4\u56de\u6240\u6709\u5b57\u6bb5\uff08\u5305\u62ec\u79c1\u6709\u5b57\u6bb5\uff09\u3002<\/li>\n\n\n\n
            • getFields()<\/code> \u8fd4\u56de\u516c\u5171\u5b57\u6bb5\u3002<\/li>\n<\/ul>\n\n\n\n
              \u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n
              import java.lang.reflect.Field;\n\nclass Person {\n    private String name;\n    public int age;\n}\n\npublic class Test {\n    public static void main(String[] args) throws NoSuchFieldException, IllegalAccessException {\n        Class<?> cls = Person.class;\n        \/\/ \u83b7\u53d6\u6240\u6709\u58f0\u660e\u7684\u5b57\u6bb5\uff0c\u5305\u62ec\u79c1\u6709\u5b57\u6bb5\n        Field[] fields = cls.getDeclaredFields();\n\n        for (Field field : fields) {\n            System.out.println(\"Field Name: \" + field.getName());\n        }\n\n        \/\/ \u8bbf\u95ee\u79c1\u6709\u5b57\u6bb5\n        Field nameField = cls.getDeclaredField(\"name\");\n        nameField.setAccessible(true);  \/\/ \u5141\u8bb8\u8bbf\u95ee\u79c1\u6709\u5b57\u6bb5\n        Person person = new Person();\n        nameField.set(person, \"John\");\n        System.out.println(\"Person Name: \" + nameField.get(person));\n    }\n}<\/code><\/pre>\n\n\n\n
              4.2 \u83b7\u53d6\u7c7b\u7684\u65b9\u6cd5<\/strong><\/h4>\n\n\n\n
              \u4f7f\u7528 Class<\/code> \u7c7b\u7684 getDeclaredMethods()<\/code> \u6216 getMethods()<\/code> \u65b9\u6cd5\u6765\u83b7\u53d6\u7c7b\u7684\u65b9\u6cd5\u3002<\/p>\n\n\n\n
                \n
              • getDeclaredMethods()<\/code> \u8fd4\u56de\u6240\u6709\u7684\u65b9\u6cd5\uff08\u5305\u62ec\u79c1\u6709\u65b9\u6cd5\uff09\u3002<\/li>\n\n\n\n
              • getMethods()<\/code> \u8fd4\u56de\u516c\u5171\u65b9\u6cd5\u3002<\/li>\n<\/ul>\n\n\n\n
                \u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n
                import java.lang.reflect.Method;\n\nclass Person {\n    public void greet() {\n        System.out.println(\"Hello!\");\n    }\n\n    private void sayHello() {\n        System.out.println(\"Private Hello!\");\n    }\n}\n\npublic class Test {\n    public static void main(String[] args) throws Exception {\n        Class<?> cls = Person.class;\n        \/\/ \u83b7\u53d6\u6240\u6709\u58f0\u660e\u7684\u65b9\u6cd5\uff0c\u5305\u62ec\u79c1\u6709\u65b9\u6cd5\n        Method[] methods = cls.getDeclaredMethods();\n\n        for (Method method : methods) {\n            System.out.println(\"Method Name: \" + method.getName());\n        }\n\n        \/\/ \u8bbf\u95ee\u79c1\u6709\u65b9\u6cd5\n        Method privateMethod = cls.getDeclaredMethod(\"sayHello\");\n        privateMethod.setAccessible(true);  \/\/ \u5141\u8bb8\u8bbf\u95ee\u79c1\u6709\u65b9\u6cd5\n        Person person = new Person();\n        privateMethod.invoke(person);  \/\/ \u52a8\u6001\u8c03\u7528\u79c1\u6709\u65b9\u6cd5\n    }\n}<\/code><\/pre>\n\n\n\n
                4.3 \u83b7\u53d6\u7c7b\u7684\u6784\u9020\u65b9\u6cd5<\/strong><\/h4>\n\n\n\n
                \u4f7f\u7528 Class<\/code> \u7c7b\u7684 getDeclaredConstructors()<\/code> \u6216 getConstructors()<\/code> \u65b9\u6cd5\u6765\u83b7\u53d6\u7c7b\u7684\u6784\u9020\u65b9\u6cd5\u3002<\/p>\n\n\n\n
                  \n
                • getDeclaredConstructors()<\/code> \u8fd4\u56de\u6240\u6709\u7684\u6784\u9020\u65b9\u6cd5\uff08\u5305\u62ec\u79c1\u6709\u6784\u9020\u65b9\u6cd5\uff09\u3002<\/li>\n\n\n\n
                • getConstructors()<\/code> \u8fd4\u56de\u516c\u5171\u6784\u9020\u65b9\u6cd5\u3002<\/li>\n<\/ul>\n\n\n\n
                  \u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n
                  import java.lang.reflect.Constructor;\n\nclass Person {\n    private String name;\n    public int age;\n\n    public Person(String name, int age) {\n        this.name = name;\n        this.age = age;\n    }\n}\n\npublic class Test {\n    public static void main(String[] args) throws Exception {\n        Class<?> cls = Person.class;\n        \/\/ \u83b7\u53d6\u6240\u6709\u58f0\u660e\u7684\u6784\u9020\u65b9\u6cd5\uff0c\u5305\u62ec\u79c1\u6709\u6784\u9020\u65b9\u6cd5\n        Constructor<?>[] constructors = cls.getDeclaredConstructors();\n\n        for (Constructor<?> constructor : constructors) {\n            System.out.println(\"Constructor: \" + constructor.getName());\n        }\n\n        \/\/ \u4f7f\u7528\u6784\u9020\u65b9\u6cd5\u521b\u5efa\u5b9e\u4f8b\n        Constructor<?> constructor = cls.getDeclaredConstructor(String.class, int.class);\n        constructor.setAccessible(true);\n        Person person = (Person) constructor.newInstance(\"John\", 25);\n        System.out.println(\"Person Name: \" + person.name + \", Age: \" + person.age);\n    }\n}<\/code><\/pre>\n\n\n\n
                  5. \u52a8\u6001\u521b\u5efa\u5bf9\u8c61\u548c\u8c03\u7528\u65b9\u6cd5<\/strong><\/h3>\n\n\n\n
                  \u901a\u8fc7\u53cd\u5c04\uff0c\u53ef\u4ee5\u5728\u8fd0\u884c\u65f6\u52a8\u6001\u521b\u5efa\u5bf9\u8c61\uff0c\u5e76\u8c03\u7528\u65b9\u6cd5\u3002\u8fd9\u5bf9\u4e8e\u4e00\u4e9b\u6846\u67b6\u548c\u5de5\u5177\u975e\u5e38\u91cd\u8981\u3002<\/p>\n\n\n\n
                  5.1 \u52a8\u6001\u521b\u5efa\u5bf9\u8c61<\/strong><\/h4>\n\n\n\n
                  \u4f7f\u7528 newInstance()<\/code> \u65b9\u6cd5\u6216 Constructor<\/code> \u7c7b\u7684 newInstance()<\/code> \u65b9\u6cd5\u53ef\u4ee5\u52a8\u6001\u521b\u5efa\u5bf9\u8c61\u3002<\/p>\n\n\n\n
                  Class<?> cls = Class.forName(\"Person\");\nPerson person = (Person) cls.newInstance();<\/code><\/pre>\n\n\n\n
                  5.2 \u52a8\u6001\u8c03\u7528\u65b9\u6cd5<\/strong><\/h4>\n\n\n\n
                  \u4f7f\u7528 Method<\/code> \u7c7b\u7684 invoke()<\/code> \u65b9\u6cd5\u53ef\u4ee5\u52a8\u6001\u8c03\u7528\u65b9\u6cd5\u3002<\/p>\n\n\n\n
                  Method method = cls.getMethod(\"greet\");\nmethod.invoke(person);<\/code><\/pre>\n\n\n\n
                  6. \u53cd\u5c04\u7684\u5e94\u7528\u573a\u666f<\/strong><\/h3>\n\n\n\n
                  \u53cd\u5c04\u901a\u5e38\u5e94\u7528\u4e8e\u4ee5\u4e0b\u51e0\u4e2a\u573a\u666f\uff1a<\/p>\n\n\n\n
                    \n
                  1. \u6846\u67b6\u5f00\u53d1<\/strong>\uff1a\u5982 Spring\u3001Hibernate \u7b49\u6846\u67b6\u5e7f\u6cdb\u4f7f\u7528\u53cd\u5c04\u6765\u52a8\u6001\u52a0\u8f7d\u7c7b\u3001\u521b\u5efa\u5bf9\u8c61\u3001\u8c03\u7528\u65b9\u6cd5\u7b49\u3002<\/li>\n\n\n\n
                  2. \u63d2\u4ef6\u5316\u7cfb\u7edf<\/strong>\uff1a\u53cd\u5c04\u53ef\u4ee5\u5728\u8fd0\u884c\u65f6\u52a8\u6001\u52a0\u8f7d\u548c\u8c03\u7528\u63d2\u4ef6\u3002<\/li>\n\n\n\n
                  3. \u8c03\u8bd5\u548c\u6d4b\u8bd5<\/strong>\uff1a\u53cd\u5c04\u53ef\u4ee5\u5e2e\u52a9\u5f00\u53d1\u8005\u83b7\u53d6\u7c7b\u7684\u7ed3\u6784\u4fe1\u606f\uff0c\u7528\u4e8e\u8c03\u8bd5\u3001\u5355\u5143\u6d4b\u8bd5\u7b49\u3002<\/li>\n\n\n\n
                  4. \u5e8f\u5217\u5316\u4e0e\u53cd\u5e8f\u5217\u5316<\/strong>\uff1a\u53cd\u5c04\u53ef\u4ee5\u5e2e\u52a9\u5c06\u5bf9\u8c61\u8f6c\u6362\u4e3a\u5b57\u8282\u6d41\uff08\u5e8f\u5217\u5316\uff09\u548c\u4ece\u5b57\u8282\u6d41\u6062\u590d\u4e3a\u5bf9\u8c61\uff08\u53cd\u5e8f\u5217\u5316\uff09\u3002<\/li>\n<\/ol>\n\n\n\n
                    7. \u53cd\u5c04\u7684\u7f3a\u70b9<\/strong><\/h3>\n\n\n\n
                    \u867d\u7136\u53cd\u5c04\u63d0\u4f9b\u4e86\u5f88\u591a\u7075\u6d3b\u6027\uff0c\u4f46\u5b83\u4e5f\u6709\u4e00\u4e9b\u7f3a\u70b9\uff1a<\/p>\n\n\n\n
                      \n
                    • \u6027\u80fd\u5f00\u9500<\/strong>\uff1a\u7531\u4e8e\u53cd\u5c04\u9700\u8981\u5728\u8fd0\u884c\u65f6\u89e3\u6790\u7c7b\u7684\u7ed3\u6784\u4fe1\u606f\uff0c\u56e0\u6b64\u5b83\u6bd4\u76f4\u63a5\u8c03\u7528\u65b9\u6cd5\u6216\u8bbf\u95ee\u5b57\u6bb5\u8981\u6162\u3002<\/li>\n\n\n\n
                    • \u7834\u574f\u5c01\u88c5\u6027<\/strong>\uff1a\u53cd\u5c04\u53ef\u4ee5\u8bbf\u95ee\u79c1\u6709\u5b57\u6bb5\u548c\u65b9\u6cd5\uff0c\u8fd9\u53ef\u80fd\u4f1a\u7834\u574f\u7c7b\u7684\u5c01\u88c5\u6027\u3002<\/li>\n\n\n\n
                    • \u4ee3\u7801\u590d\u6742\u6027<\/strong>\uff1a\u53cd\u5c04\u4f7f\u5f97\u4ee3\u7801\u66f4\u52a0\u590d\u6742\uff0c\u96be\u4ee5\u7406\u89e3\u548c\u7ef4\u62a4\u3002<\/li>\n<\/ul>\n\n\n\n
                      8. \u603b\u7ed3<\/strong><\/h3>\n\n\n\n
                      \u53cd\u5c04\u662f Java \u7684\u4e00\u4e2a\u5f3a\u5927\u7279\u6027\uff0c\u80fd\u591f\u8ba9\u7a0b\u5e8f\u5728\u8fd0\u884c\u65f6\u52a8\u6001\u5730\u83b7\u53d6\u7c7b\u4fe1\u606f\u3001\u521b\u5efa\u5bf9\u8c61\u3001\u8c03\u7528\u65b9\u6cd5\u548c\u8bbf\u95ee\u5b57\u6bb5\u3002\u5b83\u5e38\u7528\u4e8e\u6846\u67b6\u8bbe\u8ba1\u3001\u63d2\u4ef6\u7cfb\u7edf\u3001\u5de5\u5177\u7c7b\u7b49\u573a\u666f\u3002\u867d\u7136\u53cd\u5c04\u63d0\u4f9b\u4e86\u7075\u6d3b\u6027\uff0c\u4f46\u4e5f\u9700\u8981\u6ce8\u610f\u6027\u80fd\u5f00\u9500\u548c\u4ee3\u7801\u7684\u590d\u6742\u6027\u3002\u7406\u89e3\u53cd\u5c04\u7684\u4f7f\u7528\u548c\u9002\u5f53\u7684\u5e94\u7528\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002<\/p>\n\n\n\n
                      \u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
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