java 代理

code/src/main/java/com/raorao/java/proxy/MyInvocationHandler.java

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+package com.raorao.java.proxy;
+
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+
+/**
+ * .
+ *
+ * @author Xiong Raorao
+ * @since 2018-08-23-20:31
+ */
+public class MyInvocationHandler implements InvocationHandler{
+
+  private Object object;
+
+  public MyInvocationHandler(Object object){
+    this.object = object;
+  }
+
+  @Override
+  public Object invoke(Object proxy, Method method, Object[] args)
+      throws Throwable {
+    // TODO Auto-generated method stub
+    System.out.println("MyInvocationHandler invoke begin");
+    System.out.println("proxy: "+ proxy.getClass().getName());
+    System.out.println("method: "+ method.getName());
+    for(Object o : args){
+      System.out.println("arg: "+ o);
+    }
+    //通过反射调用 被代理类的方法
+    method.invoke(object, args);
+    System.out.println("MyInvocationHandler invoke end");
+    return null;
+  }
+
+  public static void main(String [] args){
+    //创建需要被代理的类
+    Student s = new Student();
+    //这一句是生成代理类的class文件，前提是你需要在工程根目录下创建com/sun/proxy目录，不然会报找不到路径的io异常
+    System.getProperties().put("sun.misc.ProxyGenerator.saveGeneratedFiles","true");
+    //获得加载被代理类的 类加载器
+    ClassLoader loader = Thread.currentThread().getContextClassLoader();
+    //指明被代理类实现的接口
+    Class<?>[] interfaces = s.getClass().getInterfaces();
+    // 创建被代理类的委托类,之后想要调用被代理类的方法时，都会委托给这个类的invoke(Object proxy, Method method, Object[] args)方法
+    MyInvocationHandler h = new MyInvocationHandler(s);
+    //生成代理类
+    Person proxy = (Person) Proxy.newProxyInstance(loader, interfaces, h);
+    //通过代理类调用 被代理类的方法
+    proxy.sayHello("yujie.wang", 20);
+    proxy.sayGoodBye(true, 100);
+    System.out.println("end");
+  }
+
+}

code/src/main/java/com/raorao/java/proxy/Person.java

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+package com.raorao.java.proxy;
+
+/**
+ * .
+ *
+ * @author Xiong Raorao
+ * @since 2018-08-23-20:27
+ */
+public interface Person {
+
+  public void sayHello(String content, int age);
+
+  public void sayGoodBye(boolean seeAgin, double time);
+}

code/src/main/java/com/raorao/java/proxy/StaticProxyTest.java

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+package com.raorao.java.proxy;
+
+/**
+ * 静态代理测试.
+ *
+ * @author Xiong Raorao
+ * @since 2018-08-23-20:29
+ */
+public class StaticProxyTest implements Person {
+
+  private Person o;
+
+  public StaticProxyTest(Person o) {
+    this.o = o;
+  }
+
+  public static void main(String[] args) {
+    // TODO Auto-generated method stub
+    //s为被代理的对象，某些情况下 我们不希望修改已有的代码，我们采用代理来间接访问
+    Student s = new Student();
+    //创建代理类对象
+    StaticProxyTest proxy = new StaticProxyTest(s);
+    //调用代理类对象的方法
+    proxy.sayHello("welcome to java", 20);
+    System.out.println("******");
+    //调用代理类对象的方法
+    proxy.sayGoodBye(true, 100);
+
+  }
+
+  @Override
+  public void sayHello(String content, int age) {
+    // TODO Auto-generated method stub
+    System.out.println("ProxyTest sayHello begin");
+    //在代理类的方法中 间接访问被代理对象的方法
+    o.sayHello(content, age);
+    System.out.println("ProxyTest sayHello end");
+  }
+
+  @Override
+  public void sayGoodBye(boolean seeAgin, double time) {
+    // TODO Auto-generated method stub
+    System.out.println("ProxyTest sayHello begin");
+    //在代理类的方法中 间接访问被代理对象的方法
+    o.sayGoodBye(seeAgin, time);
+    System.out.println("ProxyTest sayHello end");
+  }
+}

code/src/main/java/com/raorao/java/proxy/Student.java

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+package com.raorao.java.proxy;
+
+/**
+ * .
+ *
+ * @author Xiong Raorao
+ * @since 2018-08-23-20:28
+ */
+public class Student implements Person {
+
+  @Override
+  public void sayHello(String content, int age) {
+    System.out.println("student say hello" + content + " " + age);
+  }
+
+  @Override
+  public void sayGoodBye(boolean seeAgin, double time) {
+    System.out.println("student sayGoodBye " + time + " " + seeAgin);
+  }
+}