AOP（Aspect Orient Programming），我们一般称为面向方面（切面）编程，作为面向对象的一种补充，用于处理系统中分布于各个模块的横切关注点，比如事务管理、日志、缓存等等。AOP实现的关键在于AOP框架自动创建的AOP代理，AOP代理主要分为静态代理和动态代理，静态代理的代表为AspectJ；而动态代理则以Spring AOP为代表。
AOP配置示例：
数据访问层：
package com.hanqi.dao;
public class AppuserDao {
public int deleteUser(int ids) {
System.out.println(ids +"被删除");
yichang();//抛出一个异常
return 1;
}
public void yichang() {
throw new RuntimeException("出现错误！");
}
}
切面代理层：
package com.hanqi.util;
public class LogginProxy {
public void beforeMethod() {
System.out.println("方法之前被调用！");
}
public void afterMethod() {
System.out.println("方法之后被调用！");
}
public void returnMethod() {
System.out.println("返回结果时被调用！");
}
public void throwMethod() {
System.out.println("抛出异常时被调用！");
}
/*public void aroundMethod() {
System.out.println("方法被调用");
}*/
}
spring.xml配置AOP
?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:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd"> <bean id="logginProxy" class="com.hanqi.util.LogginProxy"></bean> <bean id="appuserdao" class="com.hanqi.dao.AppuserDao"></bean> <aop:config> <!-- 配置切点 --> <aop:pointcut expression="execution(* com.hanqi.dao.*.*(..))" id="aoppointcut" /><!--execution:执行，这句意为在执行com.hanqi.dao下的所有类时都会执行切面类--> <!-- 指明切面类 --> <aop:aspect ref="logginProxy"> <aop:before method="beforeMethod" pointcut-ref="aoppointcut"/> <aop:after method="afterMethod" pointcut-ref="aoppointcut"/> <aop:after-returning method="returnMethod" pointcut-ref="aoppointcut"/> <aop:after-throwing method="throwMethod" pointcut-ref="aoppointcut"/> </aop:aspect> </aop:config> </beans>
JUnit Test测试：
package com.hanqi.util;
import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.hanqi.dao.AppuserDao;
class JUnittest {
private ClassPathXmlApplicationContext c;
private AppuserDao appuserdao;
@BeforeEach
void setUp() throws Exception {
c = new ClassPathXmlApplicationContext("spring.xml");
appuserdao = c.getBean(AppuserDao.class);
}
@AfterEach
void tearDown() throws Exception {
c.close();
}
@Test
void test() {
appuserdao.deleteUser(55);
}
}
打印结果：
使用注解配置AOP
spring.xml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:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd"> <context:component-scan base-package="com.hanqi"></context:component-scan><!--配置扫描器--> </beans>
数据访问层：
package com.hanqi.dao;
import org.springframework.stereotype.Repository;
@Repository//加到spring容器中，id名默认为类名首字母小写
public class AppuserDao {
public int deleteUser(int ids) {
System.out.println(ids +"被删除");
yichang();
return 1;
}
public void yichang() {
throw new RuntimeException("出现错误！");
}
}
AppuserService类：
package com.hanqi.service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Repository;
import com.hanqi.dao.AppuserDao;
@Repository
public class AppuserService {
@Autowired//将该类自动放到当前类中的成员变量中，默认的装配类型时byType
//@Qualifier("dao")该注解可将bean中id="dao"的类装配到该成员变量中，用于区分当类型相同时；
private AppuserDao appuserDao;
public int deleteUser(int ids) {
return appuserDao.deleteUser(ids);
}
}
代理类：
package com.hanqi.util;
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.springframework.context.annotation.EnableAspectJAutoProxy;
import org.springframework.stereotype.Repository;
@Repository//加到spring容器中，id名为类名首字母小写
@Aspect//声明当前类为切面类
@EnableAspectJAutoProxy//自动代理
public class LogginProxy {
@Before("execution(* com.hanqi.dao.*.*(..))")//声明切点
public void beforeMethod() {
System.out.println("方法之前被调用！");
}
@After("execution(* com.hanqi.dao.*.*(..))")
public void afterMethod() {
System.out.println("方法之后被调用！");
}
@AfterReturning("execution(* com.hanqi.dao.*.*(..))")
public void returnMethod() {
System.out.println("返回结果时被调用！");
}
@AfterThrowing("execution(* com.hanqi.dao.*.*(..))")
public void throwMethod() {
System.out.println("抛出异常时被调用！");
}
/*public void aroundMethod() {
System.out.println("方法被调用");
}*/
}
测试类：
package com.hanqi.util;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.hanqi.dao.AppuserDao;
import com.hanqi.service.AppuserService;
class JUnittest {
private ClassPathXmlApplicationContext c;
private AppuserDao appuserdao;
private AppuserService appuserService;
@BeforeEach
void setUp() throws Exception {
c = new ClassPathXmlApplicationContext("spring.xml");
//appuserdao = c.getBean(AppuserDao.class);
appuserService = c.getBean(AppuserService.class);
}
@AfterEach
void tearDown() throws Exception {
c.close();
}
@Test
void test() {
//appuserdao.deleteUser(55);
appuserService.deleteUser(66);
}
}
原文：https://www.cnblogs.com/wyc1991/p/9245908.html