Java.io.ByteArrayInputStream.markSupported()方法範例

java.io.ByteArrayInputStream.markSupported() 如果輸入流是否支援mark() 和reset()方法的呼叫方法返回true。對於ByteArrayInputStream類的方法總是返回true。

宣告

以下是java.io.ByteArrayInputStream.markSupported()方法的宣告：

public boolean markSupported()

引數

• NA

返回值

這種方法對於ByteArrayInputStream類返回true

異常

• NA

例子

下面的範例演示java.io.ByteArrayInputStream.markSupported()方法的用法。

package com.yiibai;

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();
      }   
   }
}

讓我們來編譯和執行上面的程式，這將產生以下結果：

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