如何使用Java代码从命令提示符更改目录

public  void VerifyFiles(File dir) throws IOException{
File[] files = dir.listFiles();

    for (File file : files) {
        //Check if directory
        if (file.isDirectory()) {
            //Recursively call file list function on the new directory
            VerifyFiles(file);
        } else {
            try {   

                ProcessBuilder builder = new ProcessBuilder(
                        "cmd.exe", "/c", "cd \" C:\Users\e843778\Documents\NetBeansProjects\EncryptedFiles\" && C:\Program Files\PGP Corporation\PGP Desktop");
                builder.redirectErrorStream(true);
                Process p = builder.start();
                Runtime rt =  Runtime.getRuntime();                          
                String query2 = "cmd /c pgpnetshare -v " + "\"" + file + "\"";
                Process proc = rt.exec(query2);
                proc.waitFor();
                System.out.println("Executing for: " + file);
                BufferedReader in = new BufferedReader(new InputStreamReader(proc.getInputStream()));
                String line = "";
                String s1 ="";
                while ((line = in.readLine()) != null)
                {
                    System.out.println(line);
                    if(line.contains("All files and folders are encrypted"))
                        s1+=line;    
                }
                System.out.println(s1);
            }
public  void VerifyFiles(File dir) throws IOExc