mybatisplus依赖：

<dependency>
       <groupId>com.baomidou</groupId>
       <artifactId>mybatis-plus-boot-starter</artifactId>
       <version>3.4.2</version>
</dependency>

mysql依赖：

<dependency>
    <groupId>com.mysql</groupId>
    <artifactId>mysql-connector-j</artifactId>
    <scope>runtime</scope>
</dependency>

 lombox依赖：

<dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <optional>true</optional>
</dependency>

数据库表数据：

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user`  (
  `id` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '唯一标识',
  `nickname` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '用户名称'
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES ('843232', '李哪吒');
INSERT INTO `user` VALUES ('994343', '杨戬');

SET FOREIGN_KEY_CHECKS = 1;

前端：

    html:

<div class="whole">
    <ul class="user_login">
          <li><label>id：</label><input type="text" name="id"  /></li>
          <li><label>姓名：</label><input type="text" name="nickname" class="name" /><span          class="prompt_mes"></span></li>
          <li><span class="bnt_login">登录</span></li>
    </ul>
  </div>

    css:

 <style>
        *{
            margin: 0;
            padding: 0;
        }
        ul{
            list-style: none;
        }
        .whole{
            margin: 0 auto;
            height: 200px;
            width: 500px;
            border: 1px solid #000000;
        }
        .user_login li{
            height: 50px;
            margin: 10px 0;
            position: relative;