boolean markSupported

描述

如果输入流支持mark（）和reset（）方法调用，则java.io.ByteArrayInputStream.markSupported（）方法返回true。对于ByteArrayInputStream，该方法始终返回true。

声明

以下是java.io.ByteArrayInputStream.markSupported（）方法的声明

public boolean markSupported()

参数

NA

返回值

对于ByteArrayInputStream，此方法返回true

异常

NA

实例

以下示例显示了java.io.ByteArrayInputStream.markSupported（）方法的用法。

package com.tutorialspoint;

  import java.io.ByteArrayInputStream;
  import java.io.IOException;

  public class ByteArratInputStreamDemo {
     public static void main(String[] args) throws IOException {
        byte[] buf = {65, 66, 67, 68, 69};
        ByteArrayInputStream bais = null;

        try {
           // create new byte array input stream
           bais = new ByteArrayInputStream(buf);

           // test support for mark() and reset() methods invocation
           boolean isMarkSupported = bais.markSupported();
           System.out.println("Is mark supported : "+isMarkSupported);
           System.out.println("Following is the proof:");

           // print bytes
           System.out.println("Byte read "+ bais.read());
           System.out.println("Byte read "+ bais.read());
           System.out.println("Byte read "+ bais.read());

           System.out.println("Mark() invocation");

           // mark() invocation;
           bais.mark(0);
           System.out.println("Byte read "+ bais.read());
           System.out.println("Byte read "+ bais.read());

           System.out.println("Reset() invocation");

           // reset() invocation
           bais.reset();
           System.out.println("Byte read "+ bais.read());
           System.out.println("Byte read "+ bais.read());

        } catch(Exception e) {
           // if I/O error occurs
           e.printStackTrace();
        } finally {
           if(bais!=null)
              bais.close();
        }   
     }
  }

让我们编译并运行上面的程序，这将产生以下结果

Is mark supported : true
  Following is the proof:
  Byte read 65
  Byte read 66
  Byte read 67
  Mark() invocation
  Byte read 68
  Byte read 69
  Reset() invocation
  Byte read 68
  Byte read 69