自定义spring拦截器@Service和@Aspect

/**
* @Service和@Aspect
第一个注解是使得TimeMonitor受Spring托管并实例化。@Aspect就是使得这个类具有AOP功能（你可以这样理解）两个注解缺一不可
eg:
*/
@Service
@Aspect
public class TimeMonitor {
//当UserServiceImpl.sayHello方法执行的时候执行此拦截器
@Around("execution(* me.laiyijie.demo.service.UserServiceImpl.sayHello(..))")

public void monitorAround(ProceedingJoinPoint pjp) throws Throwable {

System.out.println("method start time:" + System.currentTimeMillis());

Object re = pjp.proceed();

System.out.println("method end time:" + System.currentTimeMillis());

}
}

_--------------------------------------------------------------------------------------------------------------------------------------------------

/**
* @Around(“execution(* me.laiyijie.demo.service.UserServiceImpl.sayHello(..))”)
@Around表示包围一个函数，也就是可以在函数执行前做一些事情，也可以在函数执行后做一些事情
execution(* me.laiyijie.demo.service.UserServiceImpl.sayHello(..)) 这个比较好理解，就是使用表达式的方式指定了要对哪个函数进行包围！
Spring AOP 开启需要的配置：

pom.xml增加依赖（因为要用到AOP还需要不同的JAR包）
root-context.xml中增加切面相关配置
*/

root-context.xml：：：

（1）
<?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:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
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"> 
<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
<context:component-scan base-package="me.laiyijie.demo"></context:component-scan>
</beans>

xmlns:aop="http://www.springframework.org/schema/aop" 代表加入命名空间
<aop:aspectj-autoproxy></aop:aspectj-autoproxy> 使用1中引入的aop命名空间开起自动代理（自动代理具体含义后续慢慢解释，简单的理解就是AOP的实现是依靠自动代理实现的）

pom.xml：：：：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion>

<groupId>me.laiyijie</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<dependencies>

<!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.3.2.RELEASE</version>
</dependency>

<!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>1.8.9</version>
</dependency>

</dependencies>
</project>

一个简单的例子：

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
/**
* ErrorCode:
* 定义一个注解 ，错误异常的注解（）
*/
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface ErrorException {
int code() default 0;//参数
}

/**
* ErrorExceptionAspect:
*
* @author yangzhenlong
* @since 2016/7/21
*/
@Component
@Aspect
public class ErrorExceptionAspect {

//@Before("execution(* com.sarkuya.service..*.*(..))")
@Pointcut(value = "@annotation(com.mlxs.mvc.anno.ErrorException)")
private void pointcut() {
}

@Around(value = "pointcut() && @annotation(errorExecption)")
public Object around(ProceedingJoinPoint point, ErrorException errorExecption){
System.out.println("---->around");
//注解参数
System.out.println("注解参数："+ errorExecption.code());
//当前拦截的类和方法：
Class clazz = point.getTarget().getClass();
Method method = ((MethodSignature) point.getSignature()).getMethod();

String codeName = clazz.getSimpleName()+"_"+method.getName();
System.out.println("query param---->"+codeName);

//方法返回结果
Object result = null;
Object args = Arrays.asList(point.getArgs());
try {
//执行方法（可以在方法前后添加前置和后置通知）
result = point.proceed();
//校验结果
result = validateResult(result);
} catch (Throwable e) {
//记录日志
System.out.println(codeName + "()方法异常：" + e);
//打印堆栈信息
e.printStackTrace();
//设置返回信息
result = "结果：抛了异常了。。-----------------------"+e.getMessage()+"，原因："+e.getCause();
}
//返回通知
return result;

}

/**
* 方法执行后
* @param joinPoint
* @param result
*/
@AfterReturning(value = "pointcut() && @annotation(errorExecption)", returning = "result")
public Object afterReturning(JoinPoint joinPoint, ErrorException errorExecption,  Object result){
System.out.println("---->afterReturning");
String methodName = joinPoint.getSignature().getName();
System.out.println("The method " + methodName + " return with " + result);
if(result instanceof Boolean){
if(!((Boolean) result)){
result = "error----result is false";
}
}else{
if(result == null){
result = "error----result is null";
}
}
return result;
}

一个测试：

/**
* _Test:
*
* @author yangzhenlong
* @since 2016/7/21
*/
@Component("test")
public class _Test {

public static void main(String[] args) {
ApplicationContext context =
new ClassPathXmlApplicationContext("classpath*:spring/applicationContext.xml");
_Test obj = (_Test) context.getBean("test");
System.out.println("==========>"+obj.test());
//System.out.println("==========>"+obj.test2());
}

@ErrorException(code = 100)
public Object test(){
System.out.println("---test---");
int a = 10/0;
return 20;
}

@ErrorException(code = 22)
public Object test2(){
System.out.println("---test2---");
//int a = 10/0;
return false;
}

}

结果：

---->around
注解参数：100
query param---->_Test_test
---test---
_Test_test()方法异常：java.lang.ArithmeticException: / by zero
---->afterReturning
The method test return with 结果：抛了异常了。。-----------------------/ by zero，原因：null
==========>结果：抛了异常了。。-----------------------/ by zero，原因：null
java.lang.ArithmeticException: / by zero
at com.mlxs.mvc.anno._Test.test(_Test.java:28)
at com.mlxs.mvc.anno._Test$$FastClassBySpringCGLIB$$cc5ae48c.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:717)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:85)
at com.mlxs.mvc.anno.ErrorExceptionAspect.around(ErrorExceptionAspect.java:44)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:621)
at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:610)
at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:68)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:168)
at org.springframework.aop.framework.adapter.AfterReturningAdviceInterceptor.invoke(AfterReturningAdviceInterceptor.java:52)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:168)
at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:58)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:168)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653)
at com.mlxs.mvc.anno._Test$$EnhancerBySpringCGLIB$$cbf2effd.test(<generated>)
at com.mlxs.mvc.anno._Test.main(_Test.java:21)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)