使用arthas查看类变量值核心思路是：通过实现ApplicationContextAware接口定义ApplicationUtil类，该类可以获取ApplicationContext的所有的Bean实例，然后通过arthas的ognl查看类实例中的属性值。

搭建简易Spring Boot工程

1. pom依赖

<?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>

    <groupId>zqh.test</groupId>
    <artifactId>SpringBootTest</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>


    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.19.RELEASE</version>
    </parent>


    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
    </dependencies>


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

2. Spring Boot 启动类

package com.zqh.main;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * @author fangchen
 * @date 2022-01-08 14:33
 */
@SpringBootApplication(scanBasePackages = {"com.zqh.bean"})
public class Application {

    public static void main(String[] args) {

        SpringApplication.run(Application.class, args);

    }
}

3. 实现 ApplicationContextAware 接口的工具类

package com.zqh.bean;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

/**
 * @author fangchen
 * @date 2022-01-08 14:49
 */
@Component
public class ApplicationUtil implements ApplicationContextAware {

    private static ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext args) throws BeansException {
        applicationContext = args;
    }

    public static Object getBean(String beanName) {
        return applicationContext.getBean(beanName);
    }
}

4. 查看目标类

package com.zqh.bean;

import org.springframework.stereotype.Component;

/**
 * @author fangchen
 * @date 2022-01-08 14:35
 */
@Component("testBean")
public class TestBean {

    private int a = 9;

    private String str = "this is bboy zqh!";
}

使用Arthas查看类变量值

1. 启动 Spring Boot 中的 main 方法

运行Application类，启动成功日志：

2. 下载并启动arthas

# 下载arthas
curl -O https://arthas.aliyun.com/arthas-boot.jar

# 启动arthas，并找到相应进程，选择，这里是第一个
java -jar arthas-boot.jar

[INFO] Found existing java process, please choose one and input the serial number of the process, eg : 1. Then hit ENTER.
* [1]: 71175 com.zqh.main.Application
  [2]: 70851 /Users/zhuqiuhui/.flow/resources/player.jar
  [3]: 70850 /Users/zhuqiuhui/.flow/resources/kafka.jar
  [4]: 70852 /Users/zhuqiuhui/.flow/resources/webapp.jar
  [5]: 71174 org.jetbrains.jps.cmdline.Launcher
  [6]: 36375
  [7]: 68267 /Users/zhuqiuhui/.flow/resources/kafka.jar
  [8]: 70861 org.jetbrains.idea.maven.server.RemoteMavenServer
  [9]: 70732

3. 使用arthas查看类变量值

[arthas@71175]$ ognl '@com.zqh.bean.ApplicationUtil@getBean("testBean").a'
@Integer[9]

[arthas@71175]$ ognl '@com.zqh.bean.ApplicationUtil@getBean("testBean").str'
@String[this is bboy zqh!]

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