Java Java.io.InputStreamReader.ready() 方法

描述

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

声明

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

 public boolean ready()

参数

不适用

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。

异常

IOException如果发生I / O错误。

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