日志代理（记录日志）

没有代理的情况：

定义一个接口

public interface UserDao {
public void delete(String name);
}

定义一个实现类

import java.util.logging.Level;
import java.util.logging.Logger;

public class UserDaoImpl implements UserDao {

public void delete(String name) {
Logger logger = Logger.getLogger(this.getClass().getName()); //记录当前类的日志
logger.log(Level.INFO, "before delete"); 
System.out.println("删除成功！");
logger.log(Level.INFO, "after delete");
}
}

进行测试

public class Tester {
public static void main(String[] args) {
UserDao dao = new UserDaoImpl();
dao.delete("Lucy");
}
}

测试结果为：

三月 25, 2015 8:54:25 下午 com.log.UserDaoImpl delete
信息: before delete
删除成功！
三月 25, 2015 8:54:25 下午 com.log.UserDaoImpl delete
信息: after delete

 

静态代理

实现类

public class UserDaoImpl implements UserDao {
public void delete(String name) {

}

}

代理类

import java.util.logging.Level;
import java.util.logging.Logger;
public class StaticProxy implements UserDao {
private UserDao dao;
StaticProxy(UserDao dao){
this.dao = dao;
}
Logger logger = Logger.getLogger(this.getClass().getName()); //记录当前类的日志
public void delete(String name) {
logger.log(Level.INFO, "before delete"); 
dao.delete(name);
logger.log(Level.INFO, "after delete");
}

验证

public class Tester {
public static void main(String[] args) {
UserDao dao = new StaticProxy(new UserDaoImpl());
dao.delete("Lucy");
}
}

动态代理

代理类

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.logging.Level;
import java.util.logging.Logger;

public class DynamicProxy implements InvocationHandler{
Object delegate;
Logger logger = Logger.getLogger(this.getClass().getName()); //记录当前类的日志
public Object bind(Object delegete){
this.delegate = delegete;
Class cls = delegate.getClass();
return Proxy.newProxyInstance(cls.getClassLoader(),
cls.getInterfaces(), this);
}
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
System.out.println("Proxy:"+proxy.getClass().getName());
System.out.println("method:"+method.getName());
if(args.length>0){
System.out.println(args);
}
Object obj = method.invoke(delegate, args);
String log = "方法"+method.getName()+"被"+args[0]+"执行";
logger.log(Level.INFO, log);
return obj;
}

测试类中main的内容

UserDao dao = (UserDao)new DynamicProxy().bind(new UserDaoImpl());
dao.delete("Lucy");