int 转byte[]互转

import java.nio.ByteBuffer;

public class Test {
	public static void main(String[] args) {
		byte[] b = int2byteArray(130);
		for (int i = 0; i < b.length; i++) {
			byte c = b[i];
			System.out.println("byte["+i+"] ==>"+c);
			
		}
		//int 转byte
		System.out.println((byte)130);
		
		//int 转byte[]
		ByteBuffer buffer = ByteBuffer.allocate(4);
		buffer.putInt(130);
		byte[] b1= buffer.array();
		for (int i = 0; i < b1.length; i++) {
			byte c = b[i];
			System.out.println("byte["+i+"] ==>"+c);
			
		}
		//byte[]  转Int
		ByteBuffer byteBuffer1 = ByteBuffer.wrap(new byte[]{0,0,0,1});
		System.out.println(byteBuffer1.getInt());
		
	}

	/**
	 * int值转成4字节的byte数组
	 * 
	 * @param num
	 * @return
	 */
	public static byte[] int2byteArray(int num) {
		byte[] result = new byte[4];
		result[0] = (byte) (num >>> 24);// 取最高8位放到0下标
		result[1] = (byte) (num >>> 16);// 取次高8为放到1下标
		result[2] = (byte) (num >>> 8); // 取次低8位放到2下标
		result[3] = (byte) (num); // 取最低8位放到3下标
		return result;
	}
}

 

Byte[] 和long 以及double 之间转换都可以间接使用ByteBuffer来转换