第一种：注解配置AOP
java中注解配置AOP（使用 AspectJ 类库实现的），大致分为三步：
1. 使用注解@Aspect来定义一个切面，在切面中定义切入点(@Pointcut),通知类型(@Before, @AfterReturning,@After,@AfterThrowing,@Around).
2. 开发需要被拦截的类。
3. 将切面配置到xml中，当然，我们也可以使用自动扫描Bean的方式。这样的话，那就交由Spring AoP容器管理。
另外需要引用 aspectJ 的 jar 包： aspectjweaver.jar aspectjrt.jar
实例：
User.java
package com.bjsxt.model;
public class User {
private String username;<br style="word-wrap:break-word">
private String password;<br style="word-wrap:break-word">
public String getUsername() {<br style="word-wrap:break-word">
return username;<br style="word-wrap:break-word">
}<br style="word-wrap:break-word">
public void setUsername(String username) {<br style="word-wrap:break-word">
this.username = username;<br style="word-wrap:break-word">
}<br style="word-wrap:break-word">
public String getPassword() {<br style="word-wrap:break-word">
return password;<br style="word-wrap:break-word">
}<br style="word-wrap:break-word">
public void setPassword(String password) {<br style="word-wrap:break-word">
this.password = password;<br style="word-wrap:break-word">
}<br style="word-wrap:break-word">}
/**
*接口类
*/
package com.bjsxt.dao;
import com.bjsxt.model.User;
public interface UserDAO {
public void save(User user);<br style="word-wrap:break-word">}
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实现接口：
package com.bjsxt.dao.impl;
import org.springframework.stereotype.Component;
import com.bjsxt.dao.UserDAO;
import com.bjsxt.model.User;
@Component("u")
public class UserDAOImpl implements UserDAO {
public void save(User user) {<br style="word-wrap:break-word"> System.out.println("user save11d!");<br style="word-wrap:break-word">
/*throw new RuntimeException("exception");*/ //抛异常<br style="word-wrap:break-word">
}<br style="word-wrap:break-word">}
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操作类：
package com.bjsxt.service;
import javax.annotation.Resource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Component;
import com.bjsxt.dao.UserDAO;
import com.bjsxt.model.User;
@Component("userService")
public class UserService {
private UserDAO userDAO; <br style="word-wrap:break-word">public void init() {<br style="word-wrap:break-word">
System.out.println("init");<br style="word-wrap:break-word">
}<br style="word-wrap:break-word">public void add(User user) {<br style="word-wrap:break-word">
userDAO.save(user);<br style="word-wrap:break-word">
}<br style="word-wrap:break-word">
public UserDAO getUserDAO() {<br style="word-wrap:break-word">
return userDAO;<br style="word-wrap:break-word">
}<br style="word-wrap:break-word">@Resource(name="u")<br style="word-wrap:break-word">
public void setUserDAO( UserDAO userDAO) {<br style="word-wrap:break-word">
this.userDAO = userDAO;<br style="word-wrap:break-word">
}<br style="word-wrap:break-word">public void destroy() {<br style="word-wrap:break-word">
System.out.println("destroy");<br style="word-wrap:break-word">
}<br style="word-wrap:break-word">}
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加入aop
package com.bjsxt.aop;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;
@Aspect
@Component
public class LogInterceptor {
@Pointcut("execution(public * com.bjsxt.service..*.add(..))")<br style="word-wrap:break-word">
public void myMethod(){};<br style="word-wrap:break-word">/*@Before("execution(public void com.bjsxt.dao.impl.UserDAOImpl.save(com.bjsxt.model.User))")*/<br style="word-wrap:break-word">
@Before("myMethod()")<br style="word-wrap:break-word">
public void before() {<br style="word-wrap:break-word">
System.out.println("method staet");<br style="word-wrap:break-word">
} <br style="word-wrap:break-word">
@After("myMethod()")<br style="word-wrap:break-word">
public void after() {<br style="word-wrap:break-word">
System.out.println("method after");<br style="word-wrap:break-word">
} <br style="word-wrap:break-word">
@AfterReturning("execution(public * com.bjsxt.dao..*.*(..))")<br style="word-wrap:break-word">
public void AfterReturning() {<br style="word-wrap:break-word">
System.out.println("method AfterReturning");<br style="word-wrap:break-word">
} <br style="word-wrap:break-word">
@AfterThrowing("execution(public * com.bjsxt.dao..*.*(..))")<br style="word-wrap:break-word">
public void AfterThrowing() {<br style="word-wrap:break-word">
System.out.println("method AfterThrowing");<br style="word-wrap:break-word">
} <br style="word-wrap:break-word">}
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配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"<br style="word-wrap:break-word">
xmlns:context="http://www.springframework.org/schema/context"<br style="word-wrap:break-word">
xmlns:aop="http://www.springframework.org/schema/aop"<br style="word-wrap:break-word">
xsi:schemaLocation="http://www.springframework.org/schema/beans<br style="word-wrap:break-word">http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-2.5.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
"><!-- 要添加最后2行 --><br style="word-wrap:break-word"><context:annotation-config /><br style="word-wrap:break-word">
<context:component-scan base-package="com.bjsxt"/> <!-- 自动扫描 --><br style="word-wrap:break-word">
<aop:aspectj-autoproxy/> <!-- 要添加本行 --><br style="word-wrap:break-word"></beans>
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测试类：
package com.bjsxt.service;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.bjsxt.model.User;
//Dependency Injection
//Inverse of Control
public class UserServiceTest {
@Test<br style="word-wrap:break-word">
public void testAdd() throws Exception {<br style="word-wrap:break-word">
ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");<br style="word-wrap:break-word"> UserService service = (UserService)ctx.getBean("userService");<br style="word-wrap:break-word">
System.out.println(service.getClass());<br style="word-wrap:break-word">
service.add(new User());<br style="word-wrap:break-word">
System.out.println("###");<br style="word-wrap:break-word"> ctx.destroy();<br style="word-wrap:break-word">}<br style="word-wrap:break-word">}
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结果：
class com.bjsxt.service.UserService$EnhancerByCGLIB$7b201784
method staet
user save11d!
method AfterReturning
method after
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注意：
@Aspect：意思是这个类为切面类
@Componet：因为作为切面类需要 Spring 管理起来，所以在初始化时就需要将这个类初始化加入 Spring 的管理；
@Befoe：切入点的逻辑(Advice)
execution…:切入点语法
第二种：xml配置aop
实例同上：只是配置文件不同
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"<br style="word-wrap:break-word">
xmlns:context="http://www.springframework.org/schema/context"<br style="word-wrap:break-word">
xmlns:aop="http://www.springframework.org/schema/aop"<br style="word-wrap:break-word">
xsi:schemaLocation="http://www.springframework.org/schema/beans<br style="word-wrap:break-word">http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-2.5.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
"><!-- 要添加最后2行 --><br style="word-wrap:break-word"><context:annotation-config /><br style="word-wrap:break-word">
<context:component-scan base-package="com.bjsxt"/><br style="word-wrap:break-word">
<bean id="logInterceptor" class="com.bjsxt.aop.LogInterceptor"></bean><br style="word-wrap:break-word">
<aop:config><br style="word-wrap:break-word">
<aop:pointcut expression="execution(public * com.bjsxt.service..*.add(..))" <br style="word-wrap:break-word">
id="servicePointcut"/><br style="word-wrap:break-word">
<aop:aspect id="logAspect" ref="logInterceptor"><br style="word-wrap:break-word">
<aop:before method="before" pointcut-ref="servicePointcut" /><br style="word-wrap:break-word">
</aop:aspect><br style="word-wrap:break-word"></aop:config><br style="word-wrap:break-word"></beans>
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下面的<beans>是Spring的配置标签，beans里面几个重要的属性：
xmlns：
是默认的xml文档解析格式，即spring的beans。地址是http://www.springframework.org/schema/beans。
通过设置这个属性，所有在beans里面声明的属性，可以直接通过<>来使用，比如<bean>等等。
xmlns:xsi：
是xml需要遵守的规范，通过URL可以看到，是w3的统一规范，后面通过xsi:schemaLocation来定位所有的解析文件。
xmlns:aop：
这个是重点，是我们这里需要使用到的一些语义规范，与面向切面AOP相关。
xmlns:tx:
Spring中与事务相关的配置内容。
一个XML文件，只能声明一个默认的语义解析的规范。
例如上面的xml中就只有beans一个是默认的，其他的都需要通过特定的标签来使用，比如aop，它自己有很多的属性，如果要使用，前面就必须加上aop:xxx才可以。比如上面的aop:config。
类似的，如果默认的xmlns配置的是aop相关的语义解析规范，那么在xml中就可以直接写config这种标签了。