如何使用扫描仪从命令行读取文件

Question

It wont prompt the user to enter file? Please help me

public static void main (String args []){
if (0 < args.length) { 
     File inFile = new File(args[0]); // Make sure the file exists, can read, etc...
     while (!inFile.exists()) {
      Scanner console = new Scanner (inFile);
      System.out.println ("Input file:"); //prompt user to input file
         String inFileName = console.nextLine();
         System.out.println ("Input file:"); //prompt user to input file
         inFileName =inFileName.trim(); //get rid of whitespace
           System.out.println(inFileName);
         inFile = new File (inFileName);
      } 

Answer 1

The old way :

BufferedReader reader = new BufferedReader( new InputStreamReader( System.in)); String userInput = reader.readLine();

The new way :

Console console = System.console(); 
if( console != null) { String userInput = console.readLine();

Answer 2

对于扫描仪，您需要使用。

Scanner console = new Scanner(System.in);

Answer 3

I suppose you can do the expected task with few lines of code.

public static void main(String[] args) {
        Scanner userInput = new Scanner(System.in);
        System.out.println("Input file : ");
        String inFile = userInput.next();
        System.out.println("Input file is " + inFile);
    }