标签：eve string invoke code java new owa open 一个
代理类所在包:java.lang.reflect.Proxy
JDK实现代理只需要使用newProxyInstance方法,但是该方法需要接收三个参数,完整的写法是:
static Object newProxyInstance(ClassLoader loader, Class<?>[] interfaces,InvocationHandler h )
注意该方法是在Proxy类中是静态方法,且接收的三个参数依次为:
ClassLoader loader,:指定当前目标对象使用类加载器,获取加载器的方法是固定的Class<?>[] interfaces,:目标对象实现的接口的类型,使用泛型方式确认类型InvocationHandler h:事件处理,执行目标对象的方法时,会触发事件处理器的方法,会把当前执行目标对象的方法作为参数传入Member.java实体类：
package com.dx.dynamicproxy; public class Member { private int id; private String name; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Member(int id, String name) { super(); this.id = id; this.name = name; } @Override public String toString() { return "Member [id=" + id + ", name=" + name + "]"; } }
IMemberService.java
package com.dx.dynamicproxy; public interface IMemberService { public String create(Member member); }
MemberSerivceImpl.java
package com.dx.dynamicproxy; public class MemberSerivceImpl implements IMemberService { public String create(Member member) { System.out.println("create member:" + member); return "SUCCESS"; } }
MemberServiceImplProxy.java动态代理类
package com.dx.dynamicproxy; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; public class MemberServiceImplProxy implements InvocationHandler { private Object obj; public MemberServiceImplProxy(Object obj) { this.obj = obj; } public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { before(method); Object resultValue = method.invoke(obj, args);// 真实的调用方法操作 after(method); return resultValue; } private void before(Method method) { System.out.println("before " + method); } private void after(Method method) { System.out.println("after " + method); } }
ProxyFactory.java 动态代理工厂（更通用）
package com.dx.dynamicproxy; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; import java.lang.reflect.Proxy; /** * 创建动态代理对象 动态代理不需要实现接口,但是需要指定接口类型 */ public class ProxyFactory { // 维护一个目标对象 private Object target; public ProxyFactory(Object target) { this.target = target; } /** * 给目标对象生成代理对象 */ public Object getProxyInstance() { ClassLoader classLoader = target.getClass().getClassLoader(); Class<?>[] interfaces = target.getClass().getInterfaces(); InvocationHandler invocationHandler = new InvocationHandler() { public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { before(method); // 执行目标对象方法 Object returnValue = method.invoke(target, args); after(method); return returnValue; } }; return Proxy.newProxyInstance(classLoader, interfaces, invocationHandler); } private void before(Method method) { System.out.println("before " + method); } private void after(Method method) { System.out.println("after " + method); } }
package com.dx.dynamicproxy; public class Client { public static void main(String[] args) { IMemberService baseMemberService = new MemberSerivceImpl(); // InvocationHandler handler = new MemberServiceImplProxy(baseMemberService); // Class<?> classType = handler.getClass(); // IMemberService memberService = (IMemberService) Proxy.newProxyInstance(classType.getClassLoader(), // baseMemberService.getClass().getInterfaces(), handler); // 或者 IMemberService memberService = (IMemberService) new ProxyFactory(baseMemberService).getProxyInstance(); Member member = new Member(1, "test"); // 执行invoke方法 String result = memberService.create(member); System.out.println(result); } }
标签：eve string invoke code java new owa open 一个
原文地址：https://www.cnblogs.com/yy3b2007com/p/9065303.html
