MD5字符串

import java.security.MessageDigest;

public class MD5 {
	public static char hexDigits(int v){
		String st = Integer.toHexString(v);
		return st.charAt(0);
	}
	
	public static String encrypt(String st){
		MessageDigest md = null;
		try{
			md = MessageDigest.getInstance("MD5");
			md.update(st.getBytes("utf-8"));
			byte[] bytes = md.digest();
			
			char str[] = new char[bytes.length*2];
			int k = 0;
			for(int i=0;i<bytes.length;i++){
				str[k++] = hexDigits(bytes[i]>>>4 & 0xf);
				str[k++] = hexDigits(bytes[i]&0xf);				
			}
			
			return new String(str);
		}catch(Exception e){
			e.printStackTrace();
		}
		
		return null;
	}
}