java中各种类型转换成Byte[]的工具方法

public class TestMain {  

          

        /**

         * 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[]
4000
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

         */  

        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;  

        }  

      

    }