Spring切面编程

切面编程

代码地址：

orbit-hub/spring-boot-samples at master (github.com)https://github.com/orbit-hub/spring-boot-samples/tree/master

切面执行顺序

Spring5以后顺序就一切正常
 正常：前置通知===目标方法===返回通知===后置通知
 异常: 前置通知===目标方法===异常通知===后置通知
 try{
     前置通知
     目标方法的执行
     返回通知
 }catch(){
     异常通知
 }finally{
     后置通知
 }

1、使用注解形式

• 定义注解

@Target({ ElementType.PARAMETER, ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Log {

    public String title() default "11";

}

• 定义切面

@Aspect
@Component
public class LogAspect2 {
    
    /**
     * 处理请求前执行
     */
    @Before(value = "@annotation(controllerLog)")
    public void boBefore(JoinPoint joinPoint, Log controllerLog) {
        System.out.println(controllerLog.title());
        String name = joinPoint.getSignature().getName();
        System.out.println("前置logStart()==>"+name+"....【args: "+ Arrays.asList(joinPoint.getArgs()) +"】");
    }

    /**
     * 处理完请求后执行
     *
     * @param joinPoint 切点
     */
    @AfterReturning(pointcut = "@annotation(controllerLog)", returning = "jsonResult")
    public void doAfterReturning(JoinPoint joinPoint, Log controllerLog, Object jsonResult) {
        System.out.println(controllerLog.title());
        String name = joinPoint.getSignature().getName();
        System.out.println("返回logReturn()==>"+name+"....【args: "+ Arrays.asList(joinPoint.getArgs()) +"】【result: "+jsonResult+"】");
    }
    //后置通知
    @After(value = "@annotation(controllerLog)")
    public void logEnd(JoinPoint joinPoint, Log controllerLog){
        System.out.println(controllerLog.title());
        String name = joinPoint.getSignature().getName();
        System.out.println("后置logEnd()==>"+name+"....【args: "+ Arrays.asList(joinPoint.getArgs()) +"】");
    }
    /**
     * 拦截异常操作
     *
     * @param joinPoint 切点
     * @param e 异常
     */
    @AfterThrowing(value = "@annotation(controllerLog)", throwing = "e")
    public void doAfterThrowing(JoinPoint joinPoint, Log controllerLog, Exception e) {
        System.out.println(controllerLog.title());
        String name = joinPoint.getSignature().getName();
        System.out.println("异常logError()==>"+name+"....【args: "+ Arrays.asList(joinPoint.getArgs()) +"】【exception: "+e+"】");
    }

}

• 定义目标

@Component
public class HelloService {

    @Log
    public String sayHello(String name){
        String result = "你好："+name;
        System.out.println(result);
        int length = name.length();
        return result + "---" + length;
    }
}

• 配置类

@Configuration
@EnableAspectJAutoProxy
@ComponentScan("com.orbit.aop")
public class MainConfig {

}

• 测试类

public class AnnotationMainTest {

    public static void main(String[] args) {
        ApplicationContext applicationContext =
                new AnnotationConfigApplicationContext(MainConfig.class);

        HelloService helloService = applicationContext.getBean(HelloService.class);

        helloService.sayHello("zhangsan");

    }

}

• 没有异常

11
前置logStart()==>sayHello....【args: [zhangsan]】
你好：zhangsan
11
返回logReturn()==>sayHello....【args: [zhangsan]】【result: 你好：zhangsan---8】
11
后置logEnd()==>sayHello....【args: [zhangsan]】

• 有异常

11
前置logStart()==>sayHello....【args: [zhangsan]】
你好：zhangsan
11
异常logError()==>sayHello....【args: [zhangsan]】【exception: java.lang.ArithmeticException: / by zero】
11
后置logEnd()==>sayHello....【args: [zhangsan]】
Exception in thread "main" java.lang.ArithmeticException: / by zero

2、使用切入点表达式

切入点表达式语法

语法结构： execution([ 权限修饰符 ] [ 返回类型 ] [ 类全路径 ] [ 方法名称 ]([ 参数列表 ]) )

        举例 ：对 com.orbit.aop.service.HelloService类里面的 sayHello进行增强

       execution(* com.orbit.aop.service.HelloService.sayHello(..))

• 定义切面

@Aspect //说明这是切面
@Component //切面也是容器中的组件
public class LogAspect {

    //前置通知  增强方法/增强器
    @Before("execution(* com.orbit.aop.service.HelloService.sayHello(..))")
    public void logStart(JoinPoint joinPoint){
        String name = joinPoint.getSignature().getName();
        System.out.println("前置logStart()==>"+name+"....【args: "+ Arrays.asList(joinPoint.getArgs()) +"】");
    }

    //返回通知
    @AfterReturning(value = "execution(* com.orbit.aop.service.HelloService.sayHello(..))",returning = "result")
    public void logReturn(JoinPoint joinPoint,Object result){
        String name = joinPoint.getSignature().getName();
        System.out.println("返回logReturn()==>"+name+"....【args: "+ Arrays.asList(joinPoint.getArgs()) +"】【result: "+result+"】");
    }


    //后置通知
    @After("execution(* com.orbit.aop.service.HelloService.sayHello(..))")
    public void logEnd(JoinPoint joinPoint){
        String name = joinPoint.getSignature().getName();
        System.out.println("后置logEnd()==>"+name+"....【args: "+ Arrays.asList(joinPoint.getArgs()) +"】");
    }


    //异常
    @AfterThrowing(value = "execution(* com.orbit.aop.service.HelloService.sayHello(..))",throwing = "e")
    public void logError(JoinPoint joinPoint,Exception e){
        String name = joinPoint.getSignature().getName();
        System.out.println("异常logError()==>"+name+"....【args: "+ Arrays.asList(joinPoint.getArgs()) +"】【exception: "+e+"】");
    }
}

没有异常

前置logStart()==>sayHello....【args: [zhangsan]】
你好：zhangsan
返回logReturn()==>sayHello....【args: [zhangsan]】【result: 你好：zhangsan---8】
后置logEnd()==>sayHello....【args: [zhangsan]】

有异常

前置logStart()==>sayHello....【args: [zhangsan]】
你好：zhangsan
异常logError()==>sayHello....【args: [zhangsan]】【exception: java.lang.ArithmeticException: / by zero】
后置logEnd()==>sayHello....【args: [zhangsan]】