Java中实现MD5加密的方法

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

public class MD5Encryptor {
    /**
     * 使用MD5算法对给定字符串进行加密。
     * 
     * @param data 待加密的数据
     * @return 加密后的32位十六进制字符串
     */
    public static String encryptMD5(String data) {
        if (null == data || data.isEmpty()) {
            return "";
        }
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(data.getBytes());
            byte[] digest = md.digest();
            StringBuilder hexString = new StringBuilder();
            for (byte b : digest) {
                String hex = Integer.toHexString(0xff & b);
                if (hex.length() == 1) {
                    hexString.append('0');
                }
                hexString.append(hex);
            }
            return hexString.toString();
        catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }

    // 测试方法
    public static void main(String[] args) {
        String test1 = encryptMD5("hello world");
        String test2 = encryptMD5("Hello World");
        String test3 = encryptMD5("");
        System.out.println("test1: " + test1);
        System.out.println("test2: " + test2);
        System.out.println("test3: " + test3);
    }
}