Java Java.io.InputStreamReader.ready() 方法

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  描述

  java.io.InputStreamReader.ready()方法告知此流是否已准备好被读取。
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  声明

  以下是java.io.InputStreamReader.ready()方法的声明-

   public boolean ready()

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  参数

  不适用
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  返回值

  如果保证下一次读取不会阻塞输入，则该方法返回true，否则返回false。
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  异常

  IOException如果发生I / O错误。
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  例子

  以下示例显示java.io.InputStreamReader.ready()方法的用法。

   
  package com.jc2182; 
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStreamReader;
  
  public class InputStreamReaderDemo {
     public static void main(String[] args) throws IOException {
        FileInputStream fis = null;
        InputStreamReader isr = null;
        boolean bool = false;
        int i;
        char c;
        
        try {
           // new input stream reader is created 
           fis = new FileInputStream("C:/test.txt");
           isr = new InputStreamReader(fis);
           
           // reads into the char buffer
           while((i = isr.read())!=-1) {
           
              // converts int to char
              c = (char)i;
              
              // prints the character
              System.out.println("Character read: "+c);
              
              // true if the next read is guaranteed
              bool = isr.ready();
              
              // prints
              System.out.println("Ready to read: "+bool);
           }
           
        } catch (Exception e) {
           // print error
           e.printStackTrace();
        } finally {
           // closes the stream and releases resources associated
           if(fis!=null)
              fis.close();
           if(isr!=null)
              isr.close();
        }   
     }
  }
  

  假设我们有一个文本文件c:/test.txt ，其内容如下。该文件将用作示例程序的输入-

   ABCDE

  让我们编译并运行以上程序，这将产生以下结果-

   
  Character read: A
  Ready to read: true
  Character read: B
  Ready to read: true
  Character read: C
  Ready to read: true
  Character read: D
  Ready to read: true
  Character read: E
  Ready to read: false