用户密码验证函数

public class LoginCheckUtils {
    private final static String ENCRYPT_MD5 = "MD5";
    private final static String ENCRYPT_SALT = "滴答滴";
    /**
     * 检查用户密码
     * @param userName
     * @param password
     * @param cryptograph
     * @return
     */
    public static Boolean checkPW(String userName, String password, String cryptograph){
        // 根据用户名密码加密，然后跟密文对比
        String encrypted = encrypt(userName+password);
        return encrypted.equals(cryptograph);
    }
    /**
     * 加密
     * @param txt
     * @return
     */
    public static String encrypt(String txt){
        return encrypt(txt, "MD5");
    }
    /**
     * 加密
     * @param txt
     * @return
     */
    public static String encrypt(String txt, String type){
        if(type == null || "".equals(type.trim())){
            type = ENCRYPT_MD5;
        }
        // 带盐加密
        if(ENCRYPT_MD5.equals(type)){
            return Hashing.md5()
                    .newHasher()
                    .putString(ENCRYPT_SALT+txt, Charsets.UTF_8)
                    .hash()
                    .toString();
        }else{
            throw new IllegalArgumentException("不支持的加密方式");
        }
    }
}

public class LoginCheckUtilsTest {
    String userName = "小阿飞";
    String password = "password";
    String cryptograph = "";
    @Before
    public void before(){
        cryptograph = LoginCheckUtils.encrypt(userName+password);
    }
    /**
     * 正常
     */
    @Test
    public void normalCheckPW() {
        Assert.assertTrue(LoginCheckUtils.checkPW(userName, password, cryptograph));
    }
    /**
     * 密文异常
     */
    @Test
    public void cryptographExcept(){
        Assert.assertFalse(LoginCheckUtils.checkPW(userName, password, "xxoo"));
    }
    /**
     * 用户或密码错误
     */
    @Test
    public void userOrPasswordExcept(){
        Assert.assertFalse(LoginCheckUtils.checkPW("", password, cryptograph));
        Assert.assertFalse(LoginCheckUtils.checkPW(userName, "", cryptograph));
    }
}