Java JAR清单文件自定义属性的正确添加与读取方法

Map<String, String> env = new HashMap<>();
env.put("create", "true"); // 如果JAR不存在则创建，这里我们是修改现有JAR
// 将JAR文件转换为URI，以便FileSystems可以识别为JAR文件系统
URI jarUri = jarFileToURI(jar);
try (FileSystem fileSystem = FileSystems.newFileSystem(jarUri, env)) {
    // 后续操作在try-with-resources块中进行，确保FileSystem正确关闭
    // ...
}

Path manifestPath = fileSystem.getPath("/META-INF/MANIFEST.MF");
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
Files.copy(manifestPath, byteArrayOutputStream);

// 将清单字节转换为字符串，并构建StringBuilder以便追加
StringBuilder manifestData = new StringBuilder(byteArrayOutputStream.toString().trim());

manifestData.append("
");
manifestData.append("Deployments-Version: ");
manifestData.append(testVersion); // 缺少末尾的换行符

manifestData.append("
"); // 确保新属性前有换行
manifestData.append("Deployments-Version: ");
manifestData.append(testVersion);
manifestData.append("
"); // 关键：确保新属性后有换行，作为该行的终止符

Files.copy(new ByteArrayInputStream(manifestData.toString().getBytes()), manifestPath,
        StandardCopyOption.REPLACE_EXISTING);

try (JarFile jarFile = new JarFile(jar)) {
    Manifest manifest = jarFile.getManifest();
    if (manifest != null) {
        // 获取主属性集合
        Attributes mainAttributes = manifest.getMainAttributes();
        // 通过键名获取自定义属性的值
        String deploymentVersion = mainAttributes.getValue("Deployments-Version");
        System.out.println("读取到的 Deployments-Version: " + deploymentVersion);
    } else {
        System.out.println("JAR文件没有清单或清单无法读取。");
    }
} catch (IOException e) {
    e.printStackTrace();
}

import java.io.*;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.file.*;
import java.util.HashMap;
import java.util.Map;
import java.util.jar.Attributes;
import java.util.jar.JarFile;
import java.util.jar.Manifest;

public class JarManifestModifier {

    public static void main(String[] args) throws IOException, URISyntaxException {
        // 假设JAR文件路径，请替换为您的实际路径
        File jar = new File("C:\Users\employee1234\Desktop\auth-0.1.3.jar");
        String testVersion = "1.2.3";
        String customAttributeName = "Deployments-Version";

        // 1. 修改JAR文件中的MANIFEST.MF
        System.out.println("--- 尝试修改JAR清单文件 ---");
        Map<String, String> env = new HashMap<>();
        env.put("create", "true"); // 允许创建文件系统

        try (FileSystem fileSystem = FileSystems.newFileSystem(jarFileToURI(jar), env)) {
            Path manifestPath = fileSystem.getPath("/META-INF/MANIFEST.MF");

            // 读取现有清单内容
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
            Files.copy(manifestPath, byteArrayOutputStream);

            // 将清单字节转换为字符串并构建StringBuilder
            StringBuilder manifestData = new StringBuilder(byteArrayOutputStream.toString().trim());

            // 添加自定义清单属性，确保末尾有换行符
            // 注意：如果manifestData.toString().trim()结果是空字符串，则直接添加
            if (manifestData.length() > 0) {
                manifestData.append("
"); // 确保新属性前有换行
            }
            manifestData.append(customAttributeName).append(": ").append(testVersion).append("
"); // 关键：新属性行末尾必须有换行

            // 将修改后的清单内容写回JAR
            Files.copy(new ByteArrayInputStream(manifestData.toString().getBytes()), manifestPath,
                    StandardCopyOption.REPLACE_EXISTING);

            System.out.println("清单文件修改成功，添加属性: " + customAttributeName + ": " + testVersion);
        } catch (Exception e) {
            System.err.println("修改JAR清单文件失败: " + e.getMessage());
            e.printStackTrace();
            return; // 修改失败则退出
        }

        // 2. 尝试从修改后的JAR中读取自定义属性
        System.out.println("
--- 尝试从修改后的JAR中读取自定义属性 ---");
        try (JarFile jarFile = new JarFile(jar)) {
            Manifest manifest = jarFile.getManifest();
            if (manifest != null) {
                String retrievedVersion = manifest.getMainAttributes().getValue(customAttributeName);
                System.out.println("从JAR中读取到的 " + customAttributeName + ": " + retrievedVersion);
                if (testVersion.equals(retrievedVersion)) {
                    System.out.println("自定义属性读取成功！");
                } else {
                    System.out.println("自定义属性读取失败或值不匹配！");
                }
            } else {
                System.out.println("JAR文件没有清单或清单无法读取。");
            }
        } catch (IOException e) {
            System.err.println("读取JAR清单文件失败: " + e.getMessage());
            e.printStackTrace();
        }
    }

    // 辅助方法：将File对象转换为JAR文件系统URI
    private static URI jarFileToURI(File jarFile) throws URISyntaxException {
        String sp = slashify(jarFile.getAbsoluteFile().getPath(), false);
        if (sp.startsWith("//"))
            sp = "//" + sp;
        return new URI("jar:file", null, sp, null);
    }

    // 辅助方法：将路径转换为斜杠分隔格式
    private static String slashify(String path, boolean isDirectory) {
        String p = path;
        if (File.separatorChar != '/')
            p = p.replace(File.separatorChar, '/');
        if (!p.startsWith("/"))
            p = "/" + p;
        if (!p.endsWith("/") && isDirectory)
            p = p + "/";
        return p;
    }
}