java简单实现MD5加密

1、话不多说，直接上代码-----传入字符串，返回加密码

import java.security.MessageDigest;

import java.text.NumberFormat;

public class MD5Utils {
    
    /**
     * 
     * 获取字符串加密后结果
     * 
     * @param text
     *            需要加密的字符串
     * @return
     */
    public static String md5(String text) {
        return md5(text, null);
    }

    /**
     * 获取字符串加密后结果
     * 
     * @param text
     * @param prifix
     * @return
     */
    public static String md5(String text, String prifix) {
        MessageDigest md5 = null;
        try {
            md5 = MessageDigest.getInstance("MD5");
        } catch (Exception e) {
            e.printStackTrace();
            return "";
        }

        if(null!=prifix && !"".endsWith(prifix)){
            text = prifix + text;
        }
        byte[] originalByte = text.getBytes();
        md5.update(originalByte);

        byte[] newByte = md5.digest();
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 0; i < newByte.length; i++) {
            if ((newByte[i] & 0xff) < 0x10) {
                stringBuilder.append("0");
            }
            stringBuilder.append(Long.toString(newByte[i] & 0xff, 16));
        }
        return stringBuilder.toString().toUpperCase();
    }
    
    public static String md5(String text, long userId) {
        MessageDigest md5 = null;
        try {
            md5 = MessageDigest.getInstance("MD5");
        } catch (Exception e) {
            e.printStackTrace();
            return "";
        }

        text = formatKey(userId) + text;

        byte[] originalByte = text.getBytes();
        md5.update(originalByte);

        byte[] newByte = md5.digest();
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 0; i < newByte.length; i++) {
            if ((newByte[i] & 0xff) < 0x10) {
                stringBuilder.append("0");
            }
            stringBuilder.append(Long.toString(newByte[i] & 0xff, 16));
        }
        return stringBuilder.toString().toUpperCase();
    }
    
    public static void main(String[] args) {
        System.out.println(MD5Utils.md5("admin", "admin"));
        System.out.println(MD5Utils.md5("admin"));
    }
}