ByteBuffer和String的互相转换

import java.nio.ByteBuffer;  import java.nio.CharBuffer;  import java.nio.charset.Charset;  import java.nio.charset.CharsetDecoder;    public class TopNTool  {      /**      * String 转换 ByteBuffer      * @param str      * @return      */      public static ByteBuffer getByteBuffer(String str)      {          return ByteBuffer.wrap(str.getBytes());      }        /**      * ByteBuffer 转换 String      * @param buffer      * @return      */      public static String getString(ByteBuffer buffer)      {          Charset charset = null;          CharsetDecoder decoder = null;          CharBuffer charBuffer = null;          try          {              charset = Charset.forName("UTF-8");              decoder = charset.newDecoder();              // charBuffer = decoder.decode(buffer);//用这个的话，只能输出来一次结果，第二次显示为空              charBuffer = decoder.decode(buffer.asReadOnlyBuffer());              return charBuffer.toString();          }          catch (Exception ex)          {              ex.printStackTrace();              return "";          }      }  }  

?