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工具类如下：

import java.security.MessageDigest;/** * @Author:Starry * @Description: * @Date:Created in 9:46 2018/4/13 * Modified By: */public class MD5Utils {    private static final String hexDigIts[] = {
 "0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"};    /**     * MD5加密     * @param origin 字符     * @param charsetname 编码     * @return     */    public static String MD5Encode(String origin, String charsetname){        String resultString = null;        try{            resultString = new String(origin);            MessageDigest md = MessageDigest.getInstance("MD5");            if(null == charsetname || "".equals(charsetname)){                resultString = byteArrayToHexString(md.digest(resultString.getBytes()));            }else{                resultString = byteArrayToHexString(md.digest(resultString.getBytes(charsetname)));            }        }catch (Exception e){        }        return resultString;    }    public static String byteArrayToHexString(byte b[]){        StringBuffer resultSb = new StringBuffer();        for(int i = 0; i < b.length; i++){            resultSb.append(byteToHexString(b[i]));        }        return resultSb.toString();    }    public static String byteToHexString(byte b){        int n = b;        if(n < 0){            n += 256;        }        int d1 = n / 16;        int d2 = n % 16;        return hexDigIts[d1] + hexDigIts[d2];    }}

结果如下：

String password = "starry12345";String password2 = MD5Utils.MD5Encode(password,"utf8");