java的md5加密實現代碼

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

public class Md5Code {

public String Md5(String plainText)  
{  
    System.out.println("加密前:"+plainText);  
    try {  
        MessageDigest md = MessageDigest.getInstance("MD5");  
        md.update(plainText.getBytes());  
        byte[] b = md.digest();  

        int i;  
        StringBuffer buf = new StringBuffer("");  
        for (int offset = 0; offset < b.length; offset++)   
        {  
            i = b[offset];  
            if (i<0) i+=256;  
            if(i<16)  
            buf.append("0");  
            buf.append(Integer.toHexString(i));  

        }  

        System.out.println("加密后："+buf.toString());  
        return buf.toString();  
    } catch (NoSuchAlgorithmException e) {  
        // TODO Auto-generated catch block  
        e.printStackTrace();  
    }  
    return plainText;  
}  



}  </pre>