java实现解压jar文件到某个目录/压缩某个目录为jar文件（好记性不如烂笔头）

这里实现一个小功能，仅用于记忆

功能：

1. 解压一个jar包到本地一个目录
2. 把一个目录压缩成一个jar包

/**
     * 1，读取jar包，得到class文件
     * 2，把class文件持久化到本地磁盘
     * 3，组装class文件打成一个新jar包
     * 4，新jar包提交到flink环境去执行任务
     */
    public static void main(String[] args) throws Exception {
        //解压jar文件到临时目录
        List<String> classPathList = unzipJar("D:\\Downloads\\", "D:\\IDEA_PROJECT\\Custom_operator\\flink-test\\target\\flink-1.0.jar");
        //重新压缩成jar包
        zipJar("D:\\Downloads\\","test.jar","D:\\Downloads\\");

    }

    /**
     * 将classPath路径下的所有文件，打成jar包。
     * jar包的路径是${binJarPath}\${binJarName}.jar
     *
     * 主要还是里面工具包里面的jar命令部分的代码
     * @param binJarPath 生成jar包的地址
     * @param binJarName 生成jar包的名字
     * @param classPath 所有的.class文件所在的路径
     */
    public static void zipJar(String binJarPath, String binJarName, String classPath) throws Exception {
        if (new File(classPath).exists()) {
            Class clazz = Class.forName("sun.tools.jar.Main");
            Constructor constructor = clazz.getConstructor(new Class[]{PrintStream.class, PrintStream.class, String.class});
            Object object = constructor.newInstance(System.out, System.err, "jar");
            Method method = clazz.getMethod("run", String[].class);
            String[] args = new String[5];
            args[0] = "-cvf";
            args[1] = binJarPath + binJarName;
            args[2] = "-C";
            args[3] = classPath;
            args[4] = ".";
            method.invoke(object, new Object[]{args});
        }
    }


    /**
     * 解压缩jar文件
     * @param destinationDir 要解压到的文件路径
     * @param jarPath  jar文件路径
     * @return List<String> 类路径
     * @throws IOException
     */
    public static List<String> unzipJar(String destinationDir, String jarPath) throws IOException {
        File file = new File(jarPath);
        JarFile jar = new JarFile(file);

        List<String> classPathList = new ArrayList<>();

        for (Enumeration<JarEntry> enums = jar.entries(); enums.hasMoreElements(); ) {
            JarEntry entry = (JarEntry) enums.nextElement();
            String fileName = destinationDir + File.separator + entry.getName();
            File f = new File(fileName);
            if (fileName.endsWith("/")) {
                f.mkdirs();
            }
            classPathList.add(fileName);
        }

        for (Enumeration<JarEntry> enums = jar.entries(); enums.hasMoreElements(); ) {
            JarEntry entry = (JarEntry) enums.nextElement();
            String fileName = destinationDir + File.separator + entry.getName();
            File f = new File(fileName);
            if (!fileName.endsWith("/")) {
                InputStream is = jar.getInputStream(entry);
                FileOutputStream fos = new FileOutputStream(f);
                while (is.available() > 0) {
                    fos.write(is.read());
                }
                fos.close();
                is.close();
            }
            classPathList.add(fileName);
        }
        return classPathList.stream().filter(s->s.indexOf(".class")!=-1).collect(Collectors.toList());
    }