Spring AOP

Spring 支持 AspectJ 注解切面编程

1. 使用@Aspect 声明切面。

2. 使用@After, @Before, @Around 定义建言advice，可以直接将拦截规则（切点）作为参数。

3. 其中@After, @Before, @Around 参数的拦截规则为切点（PointCut），为了是切点复用，可使用@PointCut专门定义拦截规则，然后在@After,@Before,@Around的参数中调用。

4. 其中符合条件的每一个被拦截处为连接点（JoinPoint）。

 

例：

1. 创建注解

package com.cz.aop;

import java.lang.annotation.*;

/**
 * 拦截规则注解
 * Created by Administrator on 2017/5/7.
            */
    @Target(ElementType.METHOD)
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface Action {
        String name();
        String value();
}

2. 创建基于注解的业务类

package com.cz.aop;

import org.springframework.stereotype.Service;

/**
 * 基于注解的拦截业务类
 * Created by Administrator on 2017/5/7
 */
@Service
public class DemoAnnotationService {

    @Action(name = "注解方式拦截add()操作之后", value = "注解方式拦截add()操作之前")
    public void add(){
        System.out.println("DemoAnnotationService run ");
    };
}

 3. 创建基于方法拦截业务类

package com.cz.aop;

import org.springframework.stereotype.Service;

/**
 * 基于方法的拦截业务类
 * Created by Administrator on 2017/5/7.
 */
@Service
public class DemoMethodService {

    public void add(){
        System.out.println("DemoMethodService run");
    };
}

 4. 创建切面

package com.cz.aop;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.Signature;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;

import java.lang.reflect.Method;

/**
 * 切面
 * Created by Administrator on 2017/5/7.
 */
@Aspect      // 注解切面
@Component   // Spring 组件
public class LogAspect {

    // 切入点
    @Pointcut("@annotation(com.cz.aop.Action)")
    public void annotionPointCut(){};

    @Before("annotionPointCut()")
    public void demoAnnotionBefore(JoinPoint joinPoint){
        MethodSignature signature = (MethodSignature)joinPoint.getSignature();
        Method method  = signature.getMethod();
        Action action = method.getAnnotation(Action.class);
        System.out.println(action.value());
    }

    @After("annotionPointCut()")
    public void demoAnnotionAfter(JoinPoint joinPoint){
        MethodSignature signature = (MethodSignature)joinPoint.getSignature();
        Method method = signature.getMethod();
        Action action = method.getAnnotation(Action.class);
        System.out.println(action.name());
    }

    @Before("execution(* com.cz.aop.DemoMethodService.*(..))")
    public void demoMethodBefore(JoinPoint joinPoint){
        MethodSignature methodSignature = (MethodSignature)joinPoint.getSignature();
        Method method = methodSignature.getMethod();
        System.out.println("方法拦截之前：" + method.getName());
    }

    @After("execution(* com.cz.aop.DemoMethodService.*(..))")
    public void demoMetyhodAfter(JoinPoint joinPoint){
        MethodSignature methodSignature = (MethodSignature)joinPoint.getSignature();
        Method method = methodSignature.getMethod();
        System.out.println("方法拦截之后：" + method.getName());
    }
}

 

 5. 创建JAVA配置类

package com.cz.aop;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.EnableAspectJAutoProxy;

/**
 * Created by Administrator on 2017/5/7.
 */
@Configuration
@ComponentScan("com.cz.aop")
@EnableAspectJAutoProxy
public class AopConfig {
}

 

6. 创建测试类

package com.cz.aop;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

/**
 * Created by Administrator on 2017/5/7.
 */
public class TestAop {


    public static void main(String[] args) {

        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(AopConfig.class);
        DemoAnnotationService demoAnnotationService = context.getBean(DemoAnnotationService.class);
        demoAnnotationService.add();

        DemoMethodService demoMethodService = context.getBean(DemoMethodService.class);
        demoMethodService.add();

        context.close();
    }
}

 

7. Run Application 结果