我們直接上程式碼

package cn.com.eteamsun.utils;

import java.nio.charset.Charset;

/**
 * Java基本資料型別和byte陣列相互轉化
 * @author liuyazhuang
 *
 */
public class ByteUtil {
	public static byte[] getBytes(short data) {
		byte[] bytes = new byte[2];
		bytes[0] = (byte) (data & 0xff);
		bytes[1] = (byte) ((data & 0xff00) >> 8);
		return bytes;
	}

	public static byte[] getBytes(char data) {
		byte[] bytes = new byte[2];
		bytes[0] = (byte) (data);
		bytes[1] = (byte) (data >> 8);
		return bytes;
	}

	public static byte[] getBytes(int data) {
		byte[] bytes = new byte[4];
		bytes[0] = (byte) (data & 0xff);
		bytes[1] = (byte) ((data & 0xff00) >> 8);
		bytes[2] = (byte) ((data & 0xff0000) >> 16);
		bytes[3] = (byte) ((data & 0xff000000) >> 24);
		return bytes;
	}

	public static byte[] getBytes(long data) {
		byte[] bytes = new byte[8];
		bytes[0] = (byte) (data & 0xff);
		bytes[1] = (byte) ((data >> 8) & 0xff);
		bytes[2] = (byte) ((data >> 16) & 0xff);
		bytes[3] = (byte) ((data >> 24) & 0xff);
		bytes[4] = (byte) ((data >> 32) & 0xff);
		bytes[5] = (byte) ((data >> 40) & 0xff);
		bytes[6] = (byte) ((data >> 48) & 0xff);
		bytes[7] = (byte) ((data >> 56) & 0xff);
		return bytes;
	}

	public static byte[] getBytes(float data) {
		int intBits = Float.floatToIntBits(data);
		return getBytes(intBits);
	}

	public static byte[] getBytes(double data) {
		long intBits = Double.doubleToLongBits(data);
		return getBytes(intBits);
	}

	public static byte[] getBytes(String data, String charsetName) {
		Charset charset = Charset.forName(charsetName);
		return data.getBytes(charset);
	}

	public static byte[] getBytes(String data) {
		return getBytes(data, "GBK");
	}

	public static short getShort(byte[] bytes) {
		return (short) ((0xff & bytes[0]) | (0xff00 & (bytes[1] << 8)));
	}

	public static char getChar(byte[] bytes) {
		return (char) ((0xff & bytes[0]) | (0xff00 & (bytes[1] << 8)));
	}

	public static int getInt(byte[] bytes) {
		return (0xff & bytes[0]) | (0xff00 & (bytes[1] << 8)) | (0xff0000 & (bytes[2] << 16))
				| (0xff000000 & (bytes[3] << 24));
	}

	public static long getLong(byte[] bytes) {
		return (0xffL & (long) bytes[0]) | (0xff00L & ((long) bytes[1] << 8)) | (0xff0000L & ((long) bytes[2] << 16))
				| (0xff000000L & ((long) bytes[3] << 24)) | (0xff00000000L & ((long) bytes[4] << 32))
				| (0xff0000000000L & ((long) bytes[5] << 40)) | (0xff000000000000L & ((long) bytes[6] << 48))
				| (0xff00000000000000L & ((long) bytes[7] << 56));
	}

	public static float getFloat(byte[] bytes) {
		return Float.intBitsToFloat(getInt(bytes));
	}

	public static double getDouble(byte[] bytes) {
		long l = getLong(bytes);
		System.out.println(l);
		return Double.longBitsToDouble(l);
	}

	public static String getString(byte[] bytes, String charsetName) {
		return new String(bytes, Charset.forName(charsetName));
	}

	public static String getString(byte[] bytes) {
		return getString(bytes, "GBK");
	}

	public static void main(String[] args) {
		short s = 122;
		int i = 122;
		long l = 1222222;

		char c = 'a';

		float f = 122.22f;
		double d = 122.22;

		String string = "我是好孩子";
		System.out.println(s);
		System.out.println(i);
		System.out.println(l);
		System.out.println(c);
		System.out.println(f);
		System.out.println(d);
		System.out.println(string);

		System.out.println("**************");

		System.out.println(getShort(getBytes(s)));
		System.out.println(getInt(getBytes(i)));
		System.out.println(getLong(getBytes(l)));
		System.out.println(getChar(getBytes(c)));
		System.out.println(getFloat(getBytes(f)));
		System.out.println(getDouble(getBytes(d)));
		System.out.println(getString(getBytes(string)));
	}
}