DataUtil.java

package com.acker.android;

/**
 * Created by guojinyu on 2016-8-4.
 */
public class DataUtil {

    /**
     * String转Byte数组
     *
     * @param str
     * @return
     */
    public static byte[] strToByteArray(String str) {
        if (str == null) {
            return null;
        }
        byte[] byteArray = str.getBytes();
        return byteArray;
    }

    /**
     * Byte数组转String
     *
     * @param byteArray
     * @return
     */
    public static String byteArrayToStr(byte[] byteArray) {
        if (byteArray == null) {
            return null;
        }
        String str = new String(byteArray);
        return str;
    }

    /**
     * Byte数组转十六进制String
     *
     * @param byteArray
     * @return
     */
    public static String byteArrayToHexStr(byte[] byteArray) {
        if (byteArray == null) {
            return null;
        }
        char[] hexArray = "0123456789ABCDEF".toCharArray();
        char[] hexChars = new char[byteArray.length * 2];
        for (int j = 0; j < byteArray.length; j++) {
            int v = byteArray[j] & 0xFF;
            hexChars[j * 2] = hexArray[v >>> 4];
            hexChars[j * 2 + 1] = hexArray[v & 0x0F];
        }
        return new String(hexChars);
    }

    /**
     * 十六进制String转Byte数组
     *
     * @param str
     * @return
     */
    public static byte[] hexStrToByteArray(String str) {
        if (str == null) {
            return null;
        }
        if (str.length() == 0) {
            return new byte[0];
        }
        byte[] byteArray = new byte[str.length() / 2];
        for (int i = 0; i < byteArray.length; i++) {
            String subStr = str.substring(2 * i, 2 * i + 2);
            byteArray[i] = ((byte) Integer.parseInt(subStr, 16));
        }
        return byteArray;
    }

    /**
     *  字符串md5编码
     * 
     * @param string
     * @return
     */
    public static String md5(String string) {
        byte[] hash;
        try {
            hash = MessageDigest.getInstance("MD5").digest(
                    string.getBytes("UTF-8"));
            StringBuilder hex = new StringBuilder(hash.length * 2);
            for (byte b : hash) {
                if ((b & 0xFF) < 0x10)
                    hex.append("0");
                hex.append(Integer.toHexString(b & 0xFF));
            }
            return hex.toString();
        } catch (Exception e) {
            e.printStackTrace();
            return string;
        }
    }
}