int、short转byte源码

 

package com.socket;

import java.util.Arrays;

public class Test {

 public static void main(String[] args) {
  byte[] bs = new byte[] { 1, 2, 3, 4, 5, 6 };
  System.out.println(bytes2int(bs, 0));
  System.out.println(bytes2short(bs, 4));
  System.out.println(Arrays.toString(int2bytes(16909060)));
  System.out.println(Arrays.toString(short2bytes((short) 1286)));

 }

 static int bytes2int(byte[] b, int startIndex) {
  int re = 0;
  for (int i = startIndex; i < startIndex + 4; i++) {
   re <<= 8;
   re += b[i];
  }
  return re;
 }

 static short bytes2short(byte[] b, int startIndex) {
  short re = 0;
  for (int i = startIndex; i < startIndex + 2; i++) {
   re <<= 8;
   re += b[i];
  }
  return re;
 }

 static byte[] int2bytes(int x) {
  byte[] b = new byte[4];
  for (int i = b.length; i > 0; i--) {
   b[i - 1] = (byte) x;
   x >>= 8;
  }
  return b;
 }

 static byte[] short2bytes(short x) {
  byte[] b = new byte[2];
  for (int i = b.length; i > 0; i--) {
   b[i - 1] = (byte) x;
   x >>= 8;
  }
  return b;
 }
}