java - FileWriter 和 PrintWriter 不会输出到文件

Question

我有这个代码

public User createnewproflie() throws IOException
{
    FileWriter fwriter = new FileWriter("users.txt",true); //creates new obj that permits to append text to existing file
    PrintWriter userfile = new PrintWriter(fwriter); //creates new obj that prints appending to file as the arg of the obj is a pointer(?) to the obj that permits to append
    String filename= "users.txt";
    Scanner userFile = new Scanner(filename); //creates new obj that reads from file
    User usr=new User(); //creates new user istance
    String usrname = JOptionPane.showInputDialog("Please enter user name: "); //acquires usrname

    userfile.println("USER: "+usrname+"\nHIGHSCORE: 0\nLASTPLAY: 0");     //writes usrname in file
    userfile.flush();
    usr.setName(usrname); //gives usr the selected usname

    return usr;
}

并且它没有输出到文件中...有人可以帮忙吗？ 我知道刷新会输出所有缓冲的文本，但由于某些奇怪的原因它似乎不起作用......

Answer 1

您可以将 String 与 FileWriter 一起使用，但 Scanner(String) 生成从指定字符串(而不是从文件)扫描的值。将 File 传递给 Scanner 构造函数(最好将相同的 File 传递给 FileWriter) 。并且您需要 close() 才能读取它；也许有try-with-resources

File f = new File("users.txt");
try (FileWriter fwriter = new FileWriter(f,true);
    PrintWriter userfile = new PrintWriter(fwriter);) {
    // ... Write stuff to userfile
} catch (Exception e) {
    e.printStackTrace();
}
Scanner userFile = new Scanner(f);

最后，我通常更喜欢类似 File f = new File(System.getProperty("user.home"), "user.txt"); 这样文件就保存在用户中主目录。