java中long,int,short与byte数组之间的转_new long(temp & 0xff).bytevalue()-优快云博客

本文详细介绍了在使用UDP报文时，如何将不同类型的数值数据转换为byte[]数组，以及如何从byte[]数组中恢复原始数据类型，涵盖了长整型、整型、短整型的转换方法。

在填写UDP报文的时候，常常需要把各种类型的数据转成byte[]的格式；在对端接收到报文以后，又要进行相反的过程，将byte[]转换成相应的数据类型。以下是具体的转换方法：

【转载自百度空间】

//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;
    }

    //byte数组转成long
    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;
    }

    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;
    }


    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;
    }


    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;
    }


    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;
    }