Java int类型如何获取高低位

 
    /**
     * 小端序 字节数组转int
     *
     * @param bytes
     * @return
     */
    public static int littleEndian(byte[] bytes) {
        return (bytes[0]&0XFF)
                | ((bytes[1]&0XFF) << 8)
                | ((bytes[2]&0XFF) << 16)
                | ((bytes[3]&0XFF) << 24);
    }
 
    /**
     * 大端序 字节数组转int
     *
     * @param bytes
     * @return
     */
    public static int bigEndian(byte[] bytes) {
        //System.out.println(String.format("%32s", Integer.toBinaryString(bytes[3]&0XFF)).replaceAll("\\s", "0"));
        //System.out.println(String.format("%32s", Integer.toBinaryString(((bytes[2]&0XFF) << 8)).replaceAll("\\s", "0")));
        //System.out.println(String.format("%32s", Integer.toBinaryString(((bytes[1]&0XFF) << 16)).replaceAll("\\s", "0")));
        //System.out.println(String.format("%32s", Integer.toBinaryString(((bytes[0]&0XFF) << 24)).replaceAll("\\s", "0")));
 
        return (bytes[3]&0XFF)
                | ((bytes[2]&0XFF) << 8)
                | ((bytes[1]&0XFF) << 16)
                | ((bytes[0]&0XFF) << 24);
    }
 
    /**
     * 大端序 int转字节数组
     *
     * @param i
     * @return
     */
    public static byte[] bigEndian(int i) {
        int byte1 = i & 0XFF;
        int byte2 = (i & 0XFFFF) >>> 8;
        int byte3 = (i & 0XFFFFFF) >>> 16;
        int byte4 = (i & 0XFFFFFFFF) >>> 24;
        return new byte[]{(byte) byte4, (byte) byte3, (byte) byte2, (byte) byte1};
    }
 
    /**
     * 小端序 int转字节数组
     *
     * @param i
     * @return
     */
    public static byte[] littleEndian(int i) {
        int byte1 = i & 0XFF;
        int byte2 = (i & 0XFF << 8) >> 8;
        int byte3 = (i & 0XFF << 16) >> 16;
        int byte4 = (i & 0XFF << 24) >> 24;
        return new byte[]{(byte) byte1, (byte) byte2, (byte) byte3, (byte) byte4};
    }
 
 
    public static void main(String[] args) {
        int a = new Random().nextInt();
        String s = String.format("%32s", Integer.toBinaryString(a)).replaceAll("\\s", "0");
        System.out.println("原数据:             " + s.substring(0, 8) + " " + s.substring(8, 16) + " " + s.substring(16, 24) + " " + s.substring(24, 32) + " ");
 
        byte[] bytes = bigEndian(a);
        System.out.printf("大端序-int转字节数组：");
        for (int i = 0; i < bytes.length; i++) {
            System.out.print(String.format("%8s", Integer.toBinaryString(bytes[i] & 0XFF)).replaceAll("\\s", "0") + " ");
        }
        System.out.println();
        System.out.println("大端序-字节数组转int验证:" + (bigEndian(bytes) == a));
 
        byte[] bytes2 = littleEndian(a);
        System.out.printf("小端序-int转字节数组：");
        for (int i = 0; i < bytes2.length; i++) {
            System.out.print(String.format("%8s", Integer.toBinaryString(bytes2[i] & 0XFF)).replaceAll("\\s", "0") + " ");
        }
        System.out.println();
        System.out.println("小端序-字节数组转int验证:" + (littleEndian(bytes2) == a));
    }
}
 
原数据:             10010100 11111001 01101110 00100011 
大端序-int转字节数组：10010100 11111001 01101110 00100011 
大端序-字节数组转int验证:true
小端序-int转字节数组：00100011 01101110 11111001 10010100 
小端序-字节数组转int验证:true