目录
AoP基本实现AoP 配置标签结构aop:aspect 子标签BeforeAfterAfter-throwingAfter-returningAround
实例AoP配置Logger类被切入类测试运行结果
环绕增强基本实现运行过程如图所示
总结参考内容
AoP基本实现
AoP 配置标签结构
<aop:config>
<aop:pointcut />
<aop:aspect >
<aop:Before></aop:Before>
</aop:aspect>
</aop:config>
aop:aspect 子标签
总结表格
Pointcut标签 可以设置多个，但必须在aspect标签之前
Before .. 标签必须指定 pointcut-ref 属性
Before
Before 将方法执行之前作为切入点
After
After 将方法结尾作为切入点
After-throwing
After-throwing 将方法中出现异常之后作为切入点 throwing 属性，设置抛出的异常信息参数(Exception 类型) ，在切入的方法中必须设置相应的参数(如果含有JoinPoint参数，必须在此之后)
After-returning
After-returning 将方法的返回值之后作为切入点 returning 属性，传递返回值内容(Object 类型)，切入的方法需要有相应的参数(如果含有JoinPoint参数，必须在此之后)
Around
实例
源码
AoP配置
<aop:config>
<aop:pointcut id="point" expression="execution(* com.yang..*.*(..))"/>
<aop:pointcut id="point1" expression="execution(* com.yang.test.*.*(..))"/>
<aop:aspect ref="myLogger">
<aop:before method="BeforeMethod" pointcut-ref="point" />
<aop:after method="AfterMethod" pointcut-ref="point" />
<aop:after-throwing method="AfterThrowing" pointcut-ref="point" throwing="e"/>
<aop:after-returning method="AfterReturning" pointcut-ref="point" returning="value_return" />
<aop:after method="AfterMethod" pointcut-ref="point2" />
</aop:aspect>
<aop:aspect ref="myLogger">
<aop:before method="BeforeMethod" pointcut-ref="point1" />
<aop:after method="AfterMethod" pointcut-ref="point1" />
<aop:after-throwing method="AfterThrowing" pointcut-ref="point1" throwing="e"/>
<aop:after-returning method="AfterReturning" pointcut-ref="point1" returning="value_return" />
<aop:after method="AfterMethod" pointcut-ref="point1" />
</aop:aspect>
</aop:config>
Logger类
package com
.yang
.logger
;
import org
.apache
.log4j
.Logger
;
import org
.aspectj
.lang
.JoinPoint
;
import org
.springframework
.stereotype
.Component
;
import java
.util
.Arrays
;
@Component("myLogger")
public class MyLogger {
private Logger logger
= Logger
.getLogger(MyLogger
.class);
public void BeforeMethod(JoinPoint joinPoint
){
String name
= joinPoint
.getSignature().getName();
Object target
= joinPoint
.getTarget();
Object
[] args
= joinPoint
.getArgs();
logger
.info(">> BeforeMethod >>>" + name
+ ":" + target
+ ":" + Arrays
.toString(args
));
}
public void AfterMethod(JoinPoint joinPoint
){
logger
.info(">> AfterMethod >>>" + joinPoint
.getSignature().getName() );
}
public void AfterThrowing(JoinPoint joinPoint
, Exception e
){
logger
.info(">> AfterThrowing >>>" + joinPoint
.getSignature().getName() + ":Error Message:" + e
.getMessage()) ;
}
public void AfterReturning(JoinPoint joinPoint
, Object value_return
){
logger
.info(">> afterReturning >>>" + joinPoint
.getSignature().getName() + ":Return Value:" + value_return
.toString() );
}
}
被切入类
package com
.yang
.test
;
import org
.springframework
.stereotype
.Component
;
@Component("demo")
public class Demo {
public String
method1(String arg1
, int id
){
try {
System
.out
.println("——————— Start method ———————");
int x
= 1 / 0;
System
.out
.println(x
);
return "Finish";
}catch (Exception e
){
return "Error";
}
finally {
System
.out
.println("——————— End method ———————");
}
}
}
测试
public class Test {
public static void main(String
[] args
) {
ApplicationContext applicationContext
= new ClassPathXmlApplicationContext("applicationContext.xml");
Demo demo
= ((Demo
) applicationContext
.getBean("demo"));
demo
.method1("参数1",2);
}
}
运行结果
09-03 14:52:45[INFO]com.yang.logger.MyLogger >> BeforeMethod >>>method1:com.yang.test.Demo@12359a82:[参数1, 2]
09-03 14:52:45[INFO]com.yang.logger.MyLogger >> BeforeMethod >>>method1:com.yang.test.Demo@12359a82:[参数1, 2]
——————— Start method ———————
——————— End method ———————
09-03 14:52:45[INFO]com.yang.logger.MyLogger >> AfterMethod >>>method1
09-03 14:52:45[INFO]com.yang.logger.MyLogger >> AfterMethod >>>method1
09-03 14:52:45[INFO]com.yang.logger.MyLogger >> AfterReturning >>>method1:Return Value:Error
09-03 14:52:45[INFO]com.yang.logger.MyLogger >> AfterReturning >>>method1:Return Value:Error
09-03 14:52:45[INFO]com.yang.logger.MyLogger >> AfterMethod >>>method1
09-03 14:52:45[INFO]com.yang.logger.MyLogger >> AfterMethod >>>method1
环绕增强
环绕增强可以完成以上所有的增强方法
基本实现
<aop:config>
<aop:pointcut id="point_around" expression="execution(* com.yang.test.Demo2.*(..))"/>
<aop:aspect ref="myLogger">
<aop:around method="aroundMethod" pointcut-ref="point_around" />
</aop:aspect>
</aop:config>
public void aroundMethod(ProceedingJoinPoint joinPoint
){
Object object
= null
;
logger
.info("增强前");
try {
object
= joinPoint
.proceed();
} catch (Throwable e
) {
logger
.info("Error:"+ e
.getMessage());
}
logger
.info("增强后:" + object
);
}
@Component("demo")
public class Demo {
public String
method1(String arg1
, int id
){
try {
System
.out
.println("——————— Start method ———————");
int x
= 1 / 0;
System
.out
.println(x
);
return "Finish";
}catch (Exception e
){
return "返回值:Error";
}
finally {
System
.out
.println("——————— End method ———————");
}
}
}
运行过程如图所示
将 Demo 作为被切入对象
总结
增强处理类型特点
Before前置增强处理，在目标方法前织入增强处理AfterReturning后置增强处理，在目标方法正常执行（不出现异常）后织入增强处理AfterThrowing异常增强处理，在目标方法抛出异常后织入增强处理After最终增强处理，不论方法是否抛出异常，都会在目标方法最后织入增强处理Around环绕增强处理，在目标方法的前后都可以织入增强处理
参考内容
05.AoP基本实现
09.增强处理
10.环绕增强
