\u5229\u7528InvocationHandler\u63a5\u53e3\u548cProxy\u7c7b\u7684\u9759\u6001\u65b9\u6cd5\u6211\u4eec\u53ef\u4ee5\u5b9e\u73b0\u5bf9\u4efb\u4f55\u4e00\u4e2a\u63a5\u53e3\u5bf9\u8c61\u7684\u52a8\u6001\u4ee3\u7406(\u7c7b\u4f3c\u4e8ewrapper\uff0c\u5c31\u662f\u901a\u8fc7\u5bf9proxy\u7684\u8c03\u7528\u5b9e\u73b0\u5bf9\u771f\u6b63\u8981\u8c03\u7528\u5bf9\u8c61\u7684\u64cd\u4f5c)\uff1a<\/p>\n\n\n\n
InvocationHandler\u63a5\u53e3\uff1a<\/p>\n\n\n\n
package java.lang.reflect;\npublic interface InvocationHandler {\n\tpublic Object invoke(Object proxy, Method method, Object[] args) throws Throwable;\n}\n<\/code><\/pre>\n\n\n\nProxy.newProxyInstance\u65b9\u6cd5\uff1a<\/p>\n\n\n\n
Proxy.newProxyInstance(ClassLoader loader, Class<?>[] interfaces, InvocationHandler h)\n<\/code><\/pre>\n\n\n\n\u8b6c\u5982\uff0c\u5bf9\u4e8eMyInterface\u63a5\u53e3\uff1a<\/p>\n\n\n\n
public interface MyInterface {\n void doSomething ();\n}\n<\/code><\/pre>\n\n\n\n\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u81ea\u5df1\u5b9e\u73b0\u4e00\u4e2aInvocationHandler\u63a5\u53e3(MyInvocationHandler)\uff0c\u7136\u540e\u901a\u8fc7Proxy.newProxyInstance\u65b9\u6cd5\u8fd4\u56de\u4e00\u4e2aMyInterface\u7c7b\u7684\u52a8\u6001\u4ee3\u7406(\u8fd9\u4e2a\u4ee3\u7406\u5b9e\u73b0\u4e86MyInterface\u7684\u6240\u6709\u65b9\u6cd5\uff0c\u4f46\u662f\u8fd9\u4e2a\u4ee3\u7406\u4e0d\u662f\u4e00\u4e2aMyInterface\u5bf9\u8c61\uff0c\u5b83\u5c31\u662f\u4e00\u4e2a\u4ee3\u7406\u800c\u5df2\uff0c\u4e00\u4e2a\u52a8\u6001\u521b\u5efa\u7684\u7c7b\uff0c\u901a\u8fc7\u8c03\u7528\u8fd9\u4e2a\u4ee3\u7406\u7684\u65b9\u6cd5\u5b9e\u73b0\u8c03\u7528MyInterface\u7684\u65b9\u6cd5)\u3002<\/p>\n\n\n\n
import java.lang.reflect.InvocationHandler;\nimport java.lang.reflect.Method;\nimport java.lang.reflect.Proxy;\nimport java.util.Arrays;\n\npublic class MyInvocationHandler implements InvocationHandler {\n\n @Override\n public Object invoke (Object proxy, Method method, Object[] args) throws Throwable {\n \n Arrays.stream(Thread.currentThread()\n .getStackTrace())\n .forEach(System.out::println);\n System.out.println(method);\n \n\n System.out.println(\"the invoked method: \" + method);\n return null;\n }\n\n public static void main (String[] args) {\n MyInvocationHandler handler = new MyInvocationHandler();\n\n MyInterface o = (MyInterface) Proxy.newProxyInstance(\n MyInvocationHandler.class.getClassLoader(),\n new Class[]{MyInterface.class}, handler);\n o.doSomething();\n }\n}\n<\/code><\/pre>\n\n\n\n\u5728\u4e0a\u8ff0\u4ee3\u7801\u4e2d\uff0c\u8c03\u7528\u4ee3\u7406o\u7684doSomething\u65b9\u6cd5\u65f6\uff0c\u4ee3\u7406o\u4f1a\u8c03\u7528handler\u7684invoke\u65b9\u6cd5\uff0c\u5e76\u4e14\u5206\u522b\u5c06invoke\u7684\u53c2\u6570Object proxy\u8bbe\u7f6e\u4e3a\u4ee3\u7406o\u3001\u53c2\u6570Method method\u8bbe\u7f6e\u4e3adoSomething\u65b9\u6cd5\u3001Object[] args\u8bbe\u7f6e\u4e3a\u8c03\u7528doSomething\u65f6\u4f7f\u7528\u7684\u53c2\u6570\u3002<\/p>\n\n\n\n
\u52a8\u6001\u4ee3\u7406\u7684\u4f5c\u7528<\/h1>\n\n\n\n
\u5b9e\u73b0\u6307\u5b9a\u7c7b\u7684wrapper\uff0c\u62e6\u622a\u5bf9\u8be5\u7c7b\u7684\u65b9\u6cd5\u8c03\u7528\uff1a<\/p>\n\n\n\n
import java.lang.reflect.InvocationHandler;\nimport java.lang.reflect.Method;\nimport java.lang.reflect.Proxy;\n\npublic class MyInterceptor<T> implements InvocationHandler {\n\n private T t;\n\n public MyInterceptor(T t) {\n this.t = t;\n }\n\n @Override\n public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {\n System.out.println(\"before method call : \" + method.getName());\n Object result = method.invoke(t, args);\n System.out.println(\"after method call : \" + method.getName());\n return result;\n }\n\n @SuppressWarnings(\"unchecked\")\n public static <T> T getProxy(T t, Class<? super T> interfaceType) {\n MyInterceptor handler = new MyInterceptor(t);\n return (T) Proxy.newProxyInstance(interfaceType.getClassLoader(),\n new Class<?>[]{interfaceType}, handler\n );\n }\n}\n<\/code><\/pre>\n\n\n\n