1.使用静态代理为系统操作添加安全性检查
实例结构图
业务接口定义
package com.dennist.dao;
public interface UserDao {
public void addUser(String name, String password);
public void deleteUser(int id);
public void updateUser(int id, String name, String password);
public String queryUser(int id);
}
接口的实现
package com.dennist.dao.impl;
import com.dennist.dao.UserDao;
public class UserDaoImpl implements UserDao{
@Override
public void addUser(String name, String password) {
System.out.println("UserDaoImpl.addUser()");
}
@Override
public void deleteUser(int id) {
System.out.println("UserDaoImpl.deleteUser()");
}
@Override
public String queryUser(int id) {
System.out.println("UserDaoImpl.queryUser()");
return null;
}
@Override
public void updateUser(int id, String name, String password) {
System.out.println("UserDaoImpl.updateUser()");
}
}
使用静态代理添加安全性检测
package com.dennist.dao.impl;
import com.dennist.dao.UserDao;
public class UserDaoImplProxy implements UserDao{
private UserDao userDao;
public UserDaoImplProxy(UserDao userDao){
this.userDao = userDao;
}
@Override
public void addUser(String name, String password) {
checkSecurity();
this.userDao.addUser(name, password);
}
@Override
public void deleteUser(int id) {
checkSecurity();
this.userDao.deleteUser(id);
}
@Override
public String queryUser(int id) {
checkSecurity();
return this.userDao.queryUser(id);
}
@Override
public void updateUser(int id, String name, String password) {
checkSecurity();
this.userDao.updateUser(id, name, password);
}
public void checkSecurity(){
System.out.println("---------checkSecurity---------");
}
}
客户端测试代码
package com.dennist.client;
import com.dennist.dao.UserDao;
import com.dennist.dao.impl.UserDaoImpl;
import com.dennist.dao.impl.UserDaoImplProxy;
public class ClientOpt {
public static void main(String[] args) {
UserDao userDao = new UserDaoImpl();
UserDaoImplProxy userDaoImplProxy = new UserDaoImplProxy(userDao);
userDaoImplProxy.addUser("dennisit", "dennisit@163.com");
userDaoImplProxy.deleteUser(5);
}
}
运行结果:
---------checkSecurity---------
UserDaoImpl.addUser()
---------checkSecurity---------
UserDaoImpl.deleteUser()
2.使用JDK的动态代理
需要实现java.lang.reflect.InvocationHandler接口
实例结构图
业务接口定义与实现同上,JDK代理实现代码如下
package com.dennist.dao.impl;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
public class SecurityHandler implements InvocationHandler{
private Object targetObject;
public Object newProxy(Object targetObject){
this.targetObject = targetObject;
//面向接口编程,安全认证加在接口上.
return Proxy.newProxyInstance(targetObject.getClass().getClassLoader(),
targetObject.getClass().getInterfaces(),
this);
}
@Override
public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
checkSecurity();
Object result = null;
try {
result = method.invoke(this.targetObject, args);
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
public void checkSecurity(){
System.out.println("---------checkSecurity---------");
}
}
客户端测试代码
package com.dennist.client;
import com.dennist.dao.UserDao;
import com.dennist.dao.impl.SecurityHandler;
import com.dennist.dao.impl.UserDaoImpl;
public class ClientOpt {
public static void main(String[] args) {
SecurityHandler handler = new SecurityHandler();
UserDao userDao = (UserDao) handler.newProxy(new UserDaoImpl());
userDao.addUser("zhangan", "pwd123");
userDao.deleteUser(5);
}
}
运行结果:
---------checkSecurity---------
UserDaoImpl.addUser()
---------checkSecurity---------
UserDaoImpl.deleteUser()
3.使用springAOP动态织入(使用xml配置)
springAOP默认采用JDK的动态代理.
项目结构图
业务dao与dao实现同上
定义安全检测方法
package com.spring.dao.impl;
public class SecurityHandler {
public void checkSecurity() {
System.out.println("----------checkSecurity()---------------");
}
}
applicationContext.xml中的配置
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">
<bean id="securityHandler" class="com.spring.dao.impl.SecurityHandler"/>
<bean id="userDao" class="com.spring.dao.impl.UserDaoImpl"/>
<aop:config>
<aop:aspect id="securityAspect" ref="securityHandler">
<aop:pointcut id="allAddMethod" expression="execution(* query*(..))||execution(* add*(..))"/>
<aop:before pointcut-ref="allAddMethod" method="checkSecurity"/>
</aop:aspect>
</aop:config>
</beans>
客户端测试
package com.spring.client;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.spring.dao.UserDao;
public class ClientOpt {
public static void main(String[] args) {
BeanFactory factory = new ClassPathXmlApplicationContext("applicationContext.xml");
UserDao userDao = (UserDao) factory.getBean("userDao");
userDao.addUser("zhangsan", "pwd123");
System.out.println("");
userDao.deleteUser(5);
System.out.println("");
userDao.queryUser(3);
}
}
运行效果:
----------checkSecurity()---------------
UserDaoImpl.addUser()
UserDaoImpl.deleteUser()
----------checkSecurity()---------------
UserDaoImpl.queryUser()
spring对AOP的支持
如果目标对象实现了接口,默认会采用JDK的动态代理机制实现AOP
如果目标对实现了接口,可以强制使用CGLIB实现AOP
如果目标对象没有实现接口,必须使用CGLIB生成代理,spring会自动在CGLIB和JDK动态代理之间切换.
如何强制使用CGLIB生成代理?
1.添加CGLIB库
2.在spring的配置文件中加入:<aop:aspectj-autoproxy proxy-target-class="true"/>
JDK代理和CGLIB代理的区别?
JDK代理只能对实现了接口的类生成代理,而不能针对类
CGLIB是针对类实现代理的,主要对指定的类生成一个子类,并覆盖其中的方法,因为是继承,所以不能使用final来修饰类或方法.
转载请注明出处:[http://www.cnblogs.com/dennisit/archive/2013/02/16/2913272.html]