java程序打包后的jar如下图所示：

可以看到META-INF目录下的三处均可以读取到程序的版本号：

• MANIFEST.MF
• build-info.properties
• maven/xxx/xx/pom.properties 或 pom.xml

一、MANIFEST.MF

程序版本号字段 即 Implementation-Version

Manifest-Version: 1.0
Implementation-Title: task-notification
Implementation-Version: 2.4.2
Archiver-Version: Plexus Archiver
Built-By: xxx
Implementation-Vendor-Id: com.xxx.platform
Spring-Boot-Version: 2.2.4.RELEASE
Implementation-Vendor: Xxx Education Technology Co, Inc.
Main-Class: org.springframework.boot.loader.JarLauncher
Start-Class: com.xxx.platform.notification.NotificationApplicatio
 n
Spring-Boot-Classes: BOOT-INF/classes/
Spring-Boot-Lib: BOOT-INF/lib/
Created-By: Apache Maven 3.5.4
Build-Jdk: 1.8.0_201

import org.apache.commons.codec.Charsets;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.net.URLDecoder;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.jar.JarFile;
import java.util.jar.Manifest;

public class Manifestation {
    private static final Logger logger = LoggerFactory.getLogger(Manifestation.class);

    private AtomicBoolean loaded = new AtomicBoolean(false);

    private Manifest manifest;

    // 程序版本号
    private String version = "";

    public void load() {
        if (loaded.compareAndSet(false, true)) {
            try {
                String location = URLDecoder.decode(Manifestation.class.getProtectionDomain().getCodeSource().getLocation().getPath(), Charsets.UTF_8.name());
                
                location = StringUtils.substringBefore(location, "!");
                
                if (location.startsWith("file:")) {
                    location = location.substring(5);
                }

                JarFile jarfile = new JarFile(location);
                
                this.manifest = jarfile.getManifest();
                this.version = manifest.getMainAttributes().getValue("Implementation-Version");

                logger.info("load manifest[{}]: {}", location, toString());
            } catch (Exception e) {
                logger.error("读取程序版本号出现异常", e);
            }
        }
    }

    public String version() {
        return this.version;
    }

    @Override
    public String toString() {
        return "{" + "version = " + version + "}";
    }
}

2、build-info.properties

build.artifact=task-notification
build.group=com.xxx.platform
build.name=task-notification
build.time=2023-08-15T02\:08\:33.043Z
build.version=2.4.2

这个是依赖maven插件 git-commit-id-plugin，具体在我之前的博文都有详细讲述。这里就不再赘述~

3、pom依赖

路径是maven/{基本package名}/{服务名}，读取pom.xml或者pom.properties都可以。

当然读取pom.properties相对简单，格式见下：

#Created by Apache Maven 3.5.4
#Wed Nov 02 11:29:00 CST 2022
version=1.25.11
groupId=com.xxx.platform
artifactId=user-service

如果你是CICD中需要读取版本号，需要知道Jar包的根包名，不同的项目，包名不一样。
建议采用上面两种办法去读取。