Java.io.PushbackReader.unread() 方法

package com.codingdict;



import java.io.*;



public class PushbackReaderDemo {



   public static void main(String[] args) {

      String s = "Hello World";



      // create a new StringReader

      StringReader sr = new StringReader(s);



      // create a new PushBack reader based on our string reader

      PushbackReader pr = new PushbackReader(sr, 20);



      try {



         // read the first five chars

         for (int i = 0; i < 5; i++) {

            char c = (char) pr.read();

            System.out.print("" + c);

         }



         // change line

         System.out.println();



         // unread a character

         pr.unread('F');



         // read the next char, which is the one we unread

         char c = (char) pr.read();



         // print that character

         System.out.println("" + c);



         // close the stream

         pr.close();



      } catch (IOException ex) {

         ex.printStackTrace();

      }

   }

}