Java基本类型与byte数组之间相互转换方法

package cn.teaey.utils;

import java.nio.charset.Charset;

public class ByteUtil
{
  public static byte[] getBytes(short data)
  {
    byte[] bytes = new byte[2];
    bytes[0] = (byte) (data & 0xff);
    bytes[1] = (byte) ((data & 0xff00) >> 8);
    return bytes;
  }


  public static byte[] getBytes(char data)
  {
    byte[] bytes = new byte[2];
    bytes[0] = (byte) (data);
    bytes[1] = (byte) (data >> 8);
    return bytes;
  }


  public static byte[] getBytes(int data)
  {
    byte[] bytes = new byte[4];
    bytes[0] = (byte) (data & 0xff);
    bytes[1] = (byte) ((data & 0xff00) >> 8);
    bytes[2] = (byte) ((data & 0xff0000) >> 16);
    bytes[3] = (byte) ((data & 0xff000000) >> 24);
    return bytes;
  }


  public static byte[] getBytes(long data)
  {
    byte[] bytes = new byte[8];
    bytes[0] = (byte) (data & 0xff);
    bytes[1] = (byte) ((data >> 8) & 0xff);
    bytes[2] = (byte) ((data >> 16) & 0xff);
    bytes[3] = (byte) ((data >> 24) & 0xff);
    bytes[4] = (byte) ((data >> 32) & 0xff);
    bytes[5] = (byte) ((data >> 40) & 0xff);
    bytes[6] = (byte) ((data >> 48) & 0xff);
    bytes[7] = (byte) ((data >> 56) & 0xff);
    return bytes;
  }


  public static byte[] getBytes(float data)
  {
    int intBits = Float.floatToIntBits(data);
    return getBytes(intBits);
  }


  public static byte[] getBytes(double data)
  {
    long intBits = Double.doubleToLongBits(data);
    return getBytes(intBits);
  }


  public static byte[] getBytes(String data, String charsetName)
  {
    Charset charset = Charset.forName(charsetName);
    return data.getBytes(charset);
  }


  public static byte[] getBytes(String data)
  {
    return getBytes(data, "GBK");
  }


  
  public static short getShort(byte[] bytes)
  {
    return (short) ((0xff & bytes[0]) | (0xff00 & (bytes[1] << 8)));
  }


  public static char getChar(byte[] bytes)
  {
    return (char) ((0xff & bytes[0]) | (0xff00 & (bytes[1] << 8)));
  }


  public static int getInt(byte[] bytes)
  {
    return (0xff & bytes[0]) | (0xff00 & (bytes[1] << 8)) | (0xff0000 & (bytes[2] << 16)) | (0xff000000 & (bytes[3] << 24));
  }
  
  public static long getLong(byte[] bytes)
  {
    return(0xffL & (long)bytes[0]) | (0xff00L & ((long)bytes[1] << 8)) | (0xff0000L & ((long)bytes[2] << 16)) | (0xff000000L & ((long)bytes[3] << 24))
     | (0xff00000000L & ((long)bytes[4] << 32)) | (0xff0000000000L & ((long)bytes[5] << 40)) | (0xff000000000000L & ((long)bytes[6] << 48)) | (0xff00000000000000L & ((long)bytes[7] << 56));
  }


  public static float getFloat(byte[] bytes)
  {
    return Float.intBitsToFloat(getInt(bytes));
  }


  public static double getDouble(byte[] bytes)
  {
    long l = getLong(bytes);
    System.out.println(l);
    return Double.longBitsToDouble(l);
  }


  public static String getString(byte[] bytes, String charsetName)
  {
    return new String(bytes, Charset.forName(charsetName));
  }


  public static String getString(byte[] bytes)
  {
    return getString(bytes, "GBK");
  }


  
  public static void main(String[] args)
  {
    short s = 122;
    int i = 122;
    long l = 1222222;


    char c = 'a';


    float f = 122.22f;
    double d = 122.22;


    String string = "我是好孩子";
    System.out.println(s);
    System.out.println(i);
    System.out.println(l);
    System.out.println(c);
    System.out.println(f);
    System.out.println(d);
    System.out.println(string);


    System.out.println("**************");


    System.out.println(getShort(getBytes(s)));
    System.out.println(getInt(getBytes(i)));
    System.out.println(getLong(getBytes(l)));
    System.out.println(getChar(getBytes(c)));
    System.out.println(getFloat(getBytes(f)));
    System.out.println(getDouble(getBytes(d)));
    System.out.println(getString(getBytes(string)));
  }
 
}