SpringBoot之WEB（四）

• 1. 新增AOP依賴
• 2. 編寫切面類
• 3. 執行結果
• 4. 原始碼下載

1. 新增AOP依賴

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

2. 編寫切面類

import org.aspectj.lang.
 
JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.*;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.
 
http.HttpServletRequest;
import java.util.Arrays;

/**
 * Created by HuangJun
 * 11:24 2018/11/9
 */
@Aspect
@Component
public class MyAspect {
    @Pointcut("execution(public * com.springboot.web.controller..*.*(..))")
    public void myAspect() {
    }

    /***
     * 前置通知
     * @param joinPoint
     * @throws Throwable
     */
 

    @Before("myAspect()")
    public void doBefore(JoinPoint joinPoint) throws Throwable {
        System.out.println( "===============前置通知 Start===================");
        // 接收到請求，記錄請求內容
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();

        // 記錄下請求內容
       System.out.println("URL : " + request.getRequestURL().toString());
        System.out.println("HTTP_METHOD : " + request.getMethod());
        System.out.println("IP : " + request.getRemoteAddr());
        System.out.println("CLASS_METHOD : " + joinPoint.getSignature().getDeclaringTypeName() + "." + joinPoint.getSignature().getName());
        System.out.println("ARGS : " + Arrays.toString(joinPoint.getArgs()));

        System.out.println( "===============前置通知 End===================");

    }

    /***
     * 後置通知
     */
    @After("myAspect()")
    public void doAfter(JoinPoint joinPoint){
        System.out.println( "===============後置通知 Start===================");
        System.out.println( "===============後置通知 End===================");
    }

    /***
     * 環繞通知
     */
    @Around("myAspect()")
    public void doAround(ProceedingJoinPoint jointPoint){

        try {
            System.out.println( "===============環繞通知 Start===================");
            String name = (String) jointPoint.proceed();
            jointPoint.proceed();
            System.out.println( "name=" + name);
            System.out.println( "===============環繞通知 End===================");
        } catch (Throwable e) {
            e.printStackTrace();
        }

    }

    /***
     * 返回通知
     */
    @AfterReturning("myAspect()")
    public void doAfterReturning(JoinPoint joinPoint)  {
        System.out.println( "===============返回通知 Start===================");
        System.out.println( "===============返回通知 End===================");
    }

    /***
     * 異常通知
     */
    @AfterThrowing("myAspect()")
    public void doAfterThrowing(JoinPoint joinPoint){
        System.out.println( "===============異常通知 Start===================");
        System.out.println( "===============異常通知 End===================");
    }

}

3. 執行結果

瀏覽器訪問http://localhost:8080/test/freemarker，控制檯列印輸出結果
這是實際執行結果，但仔細觀察這並不是我們期望的結果，這是因為環繞通知。環繞通知功能強大，但不好把握，我們先暫時把環繞通知註釋掉，再執行檢視結果：

這是我們期望的結果。

4. 原始碼下載

原始碼下載地址：https://download.csdn.net/download/huangjun0210/10774611