InputStream ... read (byte []) garbled

  		// 输入流
  		InputStream is = System.in;
  		try {
  			byte[] b =new byte[128];
  			is.read(b);
  			String str=new String(b);
  			System.out.println(str);
  			
  		} catch (IOException e) {
  			// TODO Auto-generated catch block
  			e.printStackTrace();
  		}
  	

This why garbled ?
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byte array that is a bunch of unused 0x00
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you this way looks like a problem , if you read the contents of the length is less than 128 how to do ?

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InputStream method used to make a string of what I read in the input string ?  

bother to paste the code, look at this post it http://cuisuqiang.iteye.com/blog/1434416

hope useful to you .
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how to solve it , because I still use that string up to make a judgment whether it is a directory or a file, because the problem can not be judged . .
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display problems
128 bytes.
front has a value , the latter has no value.
That behind the byte code 0000000000000000000000000000000000
this compilation , some computers are displayed as spaces , some computers display for your kind ? No.
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how it should read it ? I just want to give a space to put a string , and then read out the input string , why the empty also read out ? InputStream if only read byte [] ...
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InputStream method used to make a string of what I read in the input string ?
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InputStream method used to make a string of what I read in the input string ?          
  
bother to paste the code, look at this post it http://cuisuqiang.iteye.com/blog/1434416   
  
hope useful to you .  
useful, thank you.