Spring3笔记之 AOP JDK 代理

使用JDK代理,代理对象必须实现一接口

com.spring305.test.aop.dao.UserDao.java

public interface UserDao {
	void print1();
	void print2();
}

 实现方法:com.spring305.test.aop.dao.impl.UserDaoImpl.java

public class UserDaoImpl implements UserDao {
	private String name;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
	
	public UserDaoImpl(String name){
		this.name = name;
	}
	@Override
	public void print1() {
		System.out.println(UserDaoImpl.class.toString()+" print1()");

	}
	@Override
	public void print2() {
		System.out.println(UserDaoImpl.class.toString()+" print2()");

	}
}

 

com.spring305.test.aop.dao.ProxyFactory.java

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import com.spring305.test.aop.dao.impl.UserDaoImpl;

public class ProxyFactory implements InvocationHandler {

	private Object target;
	public Object createUserDaoImp(Object target){
		this.target = target;
		return Proxy.newProxyInstance(this.target.getClass().getClassLoader(), this.target.getClass().getInterfaces(),this);
	}
	
	@Override
	public Object invoke(Object arg0, Method arg1, Object[] arg2)
			throws Throwable {
		UserDaoImpl udImpl = (UserDaoImpl)target;
		Object result = null;
		if(udImpl.getName() == null){//name属性为空时才调用
			result = arg1.invoke(target, arg2);
		}
		return result;
	}

}

 测试代码:

@Test	//用户名为空，不执行方法
	public void testProxy(){
		ProxyFactory pf=new ProxyFactory();
		UserDao ud=(UserDao) pf.createUserDaoImp(new UserDaoImpl(null));
		ud.print1();
	}
	@Test	//用户名为不为空，才执行save方法
	public void testProxy2(){
		ProxyFactory pf=new ProxyFactory();
		UserDao ud=(UserDao) pf.createUserDaoImp(new UserDaoImpl("张某"));
		ud.print2();
	}