public String ChangePassword(UserInfo userInfo){ String msg = ""; if(userInfo.getPassword().equals(userInfo.getNewPassword())){ msg = "新密码不能与旧密码相同"; throw new RuntimeException("新密码不能与旧密码相同"); } User user = selectUserByPhone(User.builder().phoneNumber(userInfo.getUsername()).build()); if (user == null) { msg = "用户不存在"; throw new RuntimeException("用户不存在"); } if (!user.getPassword().equals(userInfo.getPassword())) { msg = "旧密码不正确"; throw new RuntimeException("旧密码不正确"); } if(validatePassword(userInfo.getPassword())){ user.setPassword(userInfo.getNewPassword()); userInfoMapper.updateByPrimaryKeySelective(user); msg = "修改密码成功"; } else { msg = "旧密码不正确"; throw new RuntimeException("旧密码不正确"); } return msg; }简化代码

这段代码实现了用户修改密码的功能，下面是简化后的代码：

public String changePassword(UserInfo userInfo) {
    if (userInfo.getPassword().equals(userInfo.getNewPassword())) {
        throw new RuntimeException("新密码不能与旧密码相同");
    }
    User user = selectUserByPhone(User.builder().phoneNumber(userInfo.getUsername()).build());
    if (user == null || !user.getPassword().equals(userInfo.getPassword())) {
        throw new RuntimeException("旧密码不正确");
    }
    user.setPassword(userInfo.getNewPassword());
    userInfoMapper.updateByPrimaryKeySelective(user);
    return "修改密码成功";
}

简化后的代码去掉了一些无用的变量和重复的判断语句，让代码更加清晰易懂。