小编use*_*823的帖子

我试图计算Windows中已用磁盘空间的百分比,而totaldrive表示Long中的C驱动器的总磁盘空间和Long中的freedrive dentoes可用空间.

 long totaloccupied = totaldrive - freedrive;

这里计算使用百分比

 Long Percentageused =(totaloccupied/totaldrive*100);
 System.out.println(Percentageused);

print语句返回0.有人可以提供帮助,因为我没有得到所需的值

我有以下代码来复制目录和文件,但不知道在哪里测量进度.有人可以帮助
我在哪里可以测量复制了多少并在JProgress栏中显示它

public static void copy(File src, File dest)
throws IOException{
if(src.isDirectory()){
        if(!dest.exists()){ //checking whether destination directory exisits
           dest.mkdir();
           System.out.println("Directory copied from " 
                        + src + "  to " + dest);
        }

        String files[] = src.list();

        for (String file : files) {

           File srcFile = new File(src, file);
           File destFile = new File(dest, file);

           copyFolder(srcFile,destFile);
        }
  }else{
        InputStream in = new FileInputStream(src);
          OutputStream out = new FileOutputStream(dest); 

          byte[] buffer = new byte[1024];

          int length;

          while ((length = in.read(buffer)) > 0){ …

我想检查Swing中的用户名和密码.

该检查适用于用户名,但它不适用于JPaswordfield.我发布相关代码:

//Here I get the password
Char[] pwd = jt1.getPassword(); 
String s = new String(pwd);  //converting char to string
String p = s;

//In the JButton checking username and password(Username check works fine but not passwordfield)

jb.addActionListener(new ActionListener() {
                         public void actionPerformed(ActionEvent e)
                           {
                            if ((jt.getText().length()) == 0)
                            {
                                   JFrame jf1 = new JFrame("UserName");
                                         jf1.setSize(401, 401);
                                         //jf1.setVisible(true);
                                         jf1.setDefaultCloseOperation(jf1.EXIT_ON_CLOSE);
                                         JOptionPane.showMessageDialog(jf1, "User Name is empty");
                            }

                         else if((p.length()) == 0)
                            {

                                   JFrame jf1 = new JFrame("Password");
                                         jf1.setSize(401, 401);
                                         //jf1.setVisible(true);
                                         jf1.setDefaultCloseOperation(jf1.EXIT_ON_CLOSE);
                                         JOptionPane.showMessageDialog(jf1, …