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「Java笔记」在Spring Boot中用注解快捷的使用AOP

让我们来面向切面编程吧，我们可以用AOP将某个共用的方法抽离出来，并在IOC容器中统一管理，而在Spring中是无法省略配置的，在Spring Boot中则完全不用，非常方便。下面以"记录接口的访问时长"功能场景来看看如何在 springboot 中使用AOP。

添加 spring-boot 的 aop 依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-aop</artifactId>
</dependency>

编写切面类和切面逻辑

@Aspect
@Component
public class HttpRequestAspect {

    private static final Logger log = LoggerFactory.getLogger(HttpRequestAspect.class);

    public static long startTime;
    public static long endTime;

    /*@PointCut注解表示表示横切点，哪些方法需要被横切*/
    /*切点表达式*/
    @Pointcut("execution(public * com.simons.cn.springbootdemo.controller.*.*(..))")
    /*切点签名*/
    public void print() {

    }

    /*@Before注解表示在具体的方法之前执行*/
    @Before("print()")
    public void before(JoinPoint joinPoint) {
        log.info("前置切面before……");
        startTime = System.currentTimeMillis();
        ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = requestAttributes.getRequest();
        String requestURI = request.getRequestURI();
        String remoteAddr = request.getRemoteAddr();   //这个方法取客户端ip"不够好"
        String requestMethod = request.getMethod();
        String declaringTypeName = joinPoint.getSignature().getDeclaringTypeName();
        String methodName = joinPoint.getSignature().getName();
        Object[] args = joinPoint.getArgs();
        log.info("请求url=" + requestURI + ",客户端ip=" + remoteAddr + ",请求方式=" + requestMethod + ",请求的类名=" + declaringTypeName + ",方法名=" + methodName + ",入参=" + args);
    }

    /*@After注解表示在方法执行之后执行*/
    @After("print()")
    public void after() {
        endTime = System.currentTimeMillis() - startTime;
        log.info("后置切面after……");
    }

    /*@AfterReturning注解用于获取方法的返回值*/
    @AfterReturning(pointcut = "print()", returning = "object")
    public void getAfterReturn(Object object) {
        log.info("本次接口耗时={}ms", endTime);
        log.info("afterReturning={}", object.toString());
    }
}

1.可以看到我把@PointCut(×××)给单独拎出来了，省的在@Before、@After、@AfterReturn 注解中重复写，而是直接用类似于@Before(value="print()")代替，减少重复性代码;

2.execution(public * com.simons.cn.springbootdemo.controller.*.*(..)) 表示 com.simons.cn.springbootdemo.controller 包下的所有类中的所有方法，".."表示所有方法中的参数不限个数;

编写测试类测试下

@GetMapping(value = "/index")
@ResponseBody
public String index() {
    ActivitySystemVariable systemVariable = activitySystemVariableMapper.selectByPrimaryKey(258);
    return systemVariable.toString();
}

日志输出结果，ok

2018-06-28 11:21:10.939  INFO 10696 --- [nio-8888-exec-8] c.s.cn.springbootdemo.HttpRequestAspect  : 前置切面before……
2018-06-28 11:21:10.939  INFO 10696 --- [nio-8888-exec-8] c.s.cn.springbootdemo.HttpRequestAspect  : 请求url=/index,客户端ip=0:0:0:0:0:0:0:1,请求方式=GET,请求的类名=com.simons.cn.springbootdemo.controller.IndexController,方法名=index,入参=[L<a href="https://www.miaoroom.com/tag/java" data-toggle="tooltip" title="查看更多关于 java 的文章" target="_blank">java</a>.lang.Object;@1efabee
2018-06-28 11:21:10.951  INFO 10696 --- [nio-8888-exec-8] c.s.cn.springbootdemo.HttpRequestAspect  : 后置切面after……
2018-06-28 11:21:10.951  INFO 10696 --- [nio-8888-exec-8] c.s.cn.springbootdemo.HttpRequestAspect  : 本次接口耗时=12ms
2018-06-28 11:21:10.951  INFO 10696 --- [nio-8888-exec-8] c.s.cn.springbootdemo.HttpRequestAspect  : afterReturning=ActivitySystemVariable{id=258, name='simonsfan测试', svKey='simons-key', value='simons-value', memo='simonsfan测试', typeCode='', cataLog=0, createTime=2018-06-28 11:18:19.0}

原文 https://www.miaoroom.com/code/note/springboot-aop.html

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