printlines.java

来自「java 完全探索的随书源码」· Java 代码 · 共 35 行

import java.io.*;

// This class reads lines from standard input (System.in) and
// prints each line along with its line number.

public class PrintLines extends Object
{
  public static void main(String[] args)
  {
    // Set up a line number input filter to count the line numbers
    LineNumberReader lineCounter = new LineNumberReader( new InputStreamReader( System.in ) );

    String nextLine = null;
    System.out.println( "Type any text and press return. Type 'exit' to quit the program." );
    try
    {
      // Keep going until exit is typed
      while ( (nextLine = lineCounter.readLine()).indexOf( "exit") == -1 )
      {
        // If readLine returns null, we've hit the end of the file
        if (nextLine == null) break;

        // Print out the current line number followed by the line
        System.out.print(lineCounter.getLineNumber());
        System.out.print(": ");
        System.out.println(nextLine);
      }
    }
    catch (Exception done)
    {
      done.printStackTrace();
    }
  }
}