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2019/2/2

使用SpringBoot打造記帳簿專案(十六)使用Spring AOP對方法做log

本篇將設定Spring AOP來對Controller的方法做log。

使用SpringBoot打造記帳簿專案(十二)使用Log4j2 + SLF4J記錄日誌中設定了log4j,並在HelloController.hello()中撰寫了log紀錄方法的開始和結束,但log程式混雜在業務邏輯中會讓程式看起來很雜亂,所以這邊要將log的執行改以AOP來處理。

首先在pom.xml加入Spring Boot AOP的Maven dependency

<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-aop -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-aop</artifactId>
</dependency>

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.0.BUILD-SNAPSHOT</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <groupId>idv.matt</groupId>
    <artifactId>moneynote</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    <name>moneynote</name>
    <description>moneynote</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-aop -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>

        <!-- log4j2 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-log4j2</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </pluginRepository>
        <pluginRepository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
        </pluginRepository>
    </pluginRepositories>

</project>

src/main/java下新增Aspect類別idv.matt.aop.LogAspect如下。

LogAspect.java

package idv.matt.aop;

import org.aspectj.lang.JoinPoint;
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.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

@Aspect
@Component
public class LogAspect {

    @Pointcut("execution(* idv.matt.controller..*(..))")
    public void pointcut() {
    }

    @Before("pointcut()")
    public void before(JoinPoint joinPoint) {
        Logger logger = LoggerFactory.getLogger(joinPoint.getTarget().getClass().getName());
        logger.info("start");
    }

    @After("pointcut()")
    public void after(JoinPoint joinPoint) {
        Logger logger = LoggerFactory.getLogger(joinPoint.getTarget().getClass().getName());
        logger.info("end");
    }

}

Aspect類別記得加上@Component,如此才能被Spring Boot掃描為bean。

AOP相關的觀念請參考AOP Concepts,簡單解釋幾點:

  • Aspect:AOP的Aspect類別,用來設定切入點(Pointcut)及切入的邏輯(Advice),Aspect類別上須加上@Aspect,也就是上例的LogAspect
  • Pointcut:要被AOP切入的位置,使用pointcut expression來表示,而Pointcut位置的Join point即為Advice施行的目標。上面的@Pointcut("execution(* idv.matt.controller..*(..))")即表示切入位置為idv.matt.controller下的任意method。
  • Joint point:Pointcut位置中實際的切入點,通常是一個method,也就是上面的HelloController.hello()
  • Advice:對joint point要施行的動作,有多種形式,如上面的掛有@Before@After的method即為Advice。

因為LogAspect位在idv.matt.aop,因此記得在SpringBootApplication(即MoneynoteApplication)的@ComponentScan設定掃描idv.matt.aopLogAspect才會被註冊為bean。

package idv.matt.application;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@ComponentScan(basePackages = { "idv.matt.controller, idv.matt.aop" }) // <-- here
public class MoneynoteApplication {

    public static void main(String[] args) {
        SpringApplication.run(MoneynoteApplication.class, args);
    }

}

HelloController.hello()中的log移除,改成如下:

HelloController.java

package idv.matt.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {

    @GetMapping("/hello")
    public String hello() {
        String s = "hello moneynote";
        System.out.println(s);

        return s;
    }

}

設定好後啟動應用程式,在瀏覽器輸入http://localhost:8080/moneynote/hello,執行後會在console印出下面結果。

[2019-02-02 23:16:50,510][INFO][idv.matt.controller.HelloController:23] - start
hello moneynote
[2019-02-02 23:16:50,515][INFO][idv.matt.controller.HelloController:29] - end

因為AOP將idv.matt.controller下的所有方法都設為切入點,所以在執行HelloController.hello()的先後執行LogAspect.before()LogAspect.after()中的程式。


最後將修改推到github,請先參考使用SpringBoot打造記帳簿專案(十四)提交至Github


接著請看使用SpringBoot打造記帳簿專案(十七)使用Eclipse MyBatis Generator plugin自動產生存取資料表的檔案


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