UserController

    @PatchMapping("/updatePwd")
    //@RequestBody注解，mvc框架才能自动的去读取请求体里的json数据，转换成map集合对象
    public Result updatePwd(@RequestBody Map<String,String> params){
        //1.校验数据
        String oldPwd = params.get("old_pwd");
        String newPwd = params.get("new_pwd");
        String rePwd = params.get("re_pwd");

        if (!StringUtils.hasLength(oldPwd) || !StringUtils.hasLength(newPwd) || !StringUtils.hasLength(rePwd)){
            return Result.error("缺少必要的参数");
        }

        //原密码是否正确
        //调用UserService根据用户名拿到原密码，再和old_pwd比对
        Map<String,Object> map = ThreadLocalUtil.get();
        String username = (String) map.get("username");
        User loginUser = userService.findByName(username);
        if (!loginUser.getPassword().equals(MD5Utils.string2MD5(oldPwd))){
            return Result.error("原密码填写错误");
        }
        //newPwd和rePwd是否一样
        if (!rePwd.equals(newPwd)){
            return Result.error("两次填写的新密码不一样");
        }
        //2.调用service完成密码更新
        userService.updatePwd(newPwd);
        return Result.success();
    }

 UserService

    //更新密码
    void updatePwd(String newPwd);

UserServiceImpl

    @Override
    public void updatePwd(String newPwd) {
        Map<String,Object> map = ThreadLocalUtil.get();
        Integer id = (Integer) map.get("id");
        userMapper.updatePwd(MD5Utils.string2MD5(newPwd),id);
    }

UserMapper

    //更新用户密码
    @Update("update user set password=#{string2MD5},update_time=now() where id=#{id}")
    void updatePwd(String string2MD5, Integer id);