Java 基础 byte[]与各种数据类型互相转换的简单示例

public class TestCase {      /**    * short到字节数组的转换.    */   public static byte[] shortToByte(short number) {     int temp = number;     byte[] b = new byte[2];     for (int i = 0; i < b.length; i++) {       b[i] = new Integer(temp & 0xff).byteValue();// 将最低位保存在最低位       temp = temp >> 8;// 向右移8位     }     return b;   }    /**    * 字节数组到short的转换.    */   public static short byteToShort(byte[] b) {     short s = 0;     short s0 = (short) (b[0] & 0xff);// 最低位     short s1 = (short) (b[1] & 0xff);     s1 <<= 8;     s = (short) (s0 | s1);     return s;   }         /**    * int到字节数组的转换.    */   public static byte[] intToByte(int number) {     int temp = number;     byte[] b = new byte[4];     for (int i = 0; i < b.length; i++) {       b[i] = new Integer(temp & 0xff).byteValue();// 将最低位保存在最低位       temp = temp >> 8;// 向右移8位     }     return b;   }    /**    * 字节数组到int的转换.    */   public static int byteToInt(byte[] b) {     int s = 0;     int s0 = b[0] & 0xff;// 最低位     int s1 = b[1] & 0xff;     int s2 = b[2] & 0xff;     int s3 = b[3] & 0xff;     s3 <<= 24;     s2 <<= 16;     s1 <<= 8;     s = s0 | s1 | s2 | s3;     return s;   }         /**    * long类型转成byte数组    */   public static byte[] longToByte(long number) {     long temp = number;     byte[] b = new byte[8];     for (int i = 0; i < b.length; i++) {       b[i] = new Long(temp & 0xff).byteValue();// 将最低位保存在最低位 temp = temp                             // >> 8;// 向右移8位     }     return b;   }    /**    * 字节数组到long的转换.    */   public static long byteToLong(byte[] b) {     long s = 0;     long s0 = b[0] & 0xff;// 最低位     long s1 = b[1] & 0xff;     long s2 = b[2] & 0xff;     long s3 = b[3] & 0xff;     long s4 = b[4] & 0xff;// 最低位     long s5 = b[5] & 0xff;     long s6 = b[6] & 0xff;     long s7 = b[7] & 0xff;      // s0不变     s1 <<= 8;     s2 <<= 16;     s3 <<= 24;     s4 <<= 8 * 4;     s5 <<= 8 * 5;     s6 <<= 8 * 6;     s7 <<= 8 * 7;     s = s0 | s1 | s2 | s3 | s4 | s5 | s6 | s7;     return s;   }      /**    * double到字节数组的转换.    */   public static byte[] doubleToByte(double num) {      byte[] b = new byte[8];      long l = Double.doubleToLongBits(num);      for (int i = 0; i < 8; i++) {        b[i] = new Long(l).byteValue();        l = l >> 8;      }     return b;   }      /**    * 字节数组到double的转换.    */   public static double getDouble(byte[] b) {      long m;      m = b[0];      m &= 0xff;      m |= ((long) b[1] << 8);      m &= 0xffff;      m |= ((long) b[2] << 16);      m &= 0xffffff;      m |= ((long) b[3] << 24);      m &= 0xffffffffl;      m |= ((long) b[4] << 32);      m &= 0xffffffffffl;      m |= ((long) b[5] << 40);      m &= 0xffffffffffffl;      m |= ((long) b[6] << 48);      m &= 0xffffffffffffffl;      m |= ((long) b[7] << 56);      return Double.longBitsToDouble(m);    }         /**    * float到字节数组的转换.    */   public static void floatToByte(float x) {     //先用 Float.floatToIntBits(f)转换成int   }      /**    * 字节数组到float的转换.    */   public static float getFloat(byte[] b) {      // 4 bytes      int accum = 0;      for ( int shiftBy = 0; shiftBy < 4; shiftBy++ ) {          accum |= (b[shiftBy] & 0xff) << shiftBy * 8;      }      return Float.intBitsToFloat(accum);    }      /**    * char到字节数组的转换.    */    public static byte[] charToByte(char c){     byte[] b = new byte[2];     b[0] = (byte) ((c & 0xFF00) >> 8);     b[1] = (byte) (c & 0xFF);     return b;    }        /**    * 字节数组到char的转换.    */    public static char byteToChar(byte[] b){     char c = (char) (((b[0] & 0xFF) << 8) | (b[1] & 0xFF));     return c;    }      /**    * string到字节数组的转换.    */   public static byte[] stringToByte(String str) throws UnsupportedEncodingException{     return str.getBytes("GBK");   }      /**    * 字节数组到String的转换.    */   public static String bytesToString(byte[] str) {     String keyword = null;     try {       keyword = new String(str,"GBK");     } catch (UnsupportedEncodingException e) {       e.printStackTrace();     }     return keyword;   }         /**    * object到字节数组的转换    */   @Test   public void testObject2ByteArray() throws IOException,       ClassNotFoundException {     // Object obj = "";     Integer[] obj = { 1, 3, 4 };      // // object to bytearray     ByteArrayOutputStream bo = new ByteArrayOutputStream();     ObjectOutputStream oo = new ObjectOutputStream(bo);     oo.writeObject(obj);     byte[] bytes = bo.toByteArray();     bo.close();     oo.close();     System.out.println(Arrays.toString(bytes));      Integer[] intArr = (Integer[]) testByteArray2Object(bytes);     System.out.println(Arrays.asList(intArr));       byte[] b2 = intToByte(123);     System.out.println(Arrays.toString(b2));      int a = byteToInt(b2);     System.out.println(a);    }    /**    * 字节数组到object的转换.    */   private Object testByteArray2Object(byte[] bytes) throws IOException,       ClassNotFoundException {     // byte[] bytes = null;     Object obj;     // bytearray to object     ByteArrayInputStream bi = new ByteArrayInputStream(bytes);     ObjectInputStream oi = new ObjectInputStream(bi);     obj = oi.readObject();     bi.close();     oi.close();     System.out.println(obj);     return obj;   }  }