import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
 
public class GetMD5 {
 
	public static void main(String[] args) {
		String str = "admin";
		char[] hex = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
		char[] mD5 = new char[32];
		try {
			MessageDigest md = MessageDigest.getInstance("MD5");
			md.update(str.getBytes());
			byte[] pMD5 = md.digest();
			for(int i=0; i<16; i++) {
				byte temp = pMD5[i];
 				mD5[i*2] = hex[temp>>4&0xf];
				mD5[i*2+1] = hex[temp&0xf];
			}
 
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}
		System.out.println(mD5);
	}
}

输出结果：21232F297A57A5A743894A0E4A801FC3