MD5使用

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class CreateMD5 {
    public static String getMd5(String plainTest){
        try{
            MessageDigest md = MessageDigest.getInstance("md5");
            byte[] input = plainTest.getBytes();
            md.update(input);
            byte[] b = md.digest();

            int i;

            StringBuffer sb = new StringBuffer();
            for(int k=0;k<b.length;k++){
                i=b[k];
                if(i<0){
                    i+=256;
                }
                if(i<16){
                    sb.append("0");
                }
                sb.append(Integer.toHexString(i));
            }
            //32位加密
            return sb.toString();
            //16位加密
            //return sb.toString().substring(8, 24);

        }catch(NoSuchAlgorithmException e){
            e.printStackTrace();
            return null;
        }
    }

    public static void main(String[] args){
        System.out.println(CreateMD5.getMd5("hello world"));
    }
}