ssm框架mysql自增

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(50) NOT NULL,
  `password` varchar(50) NOT NULL,
  PRIMARY KEY (`id`)
);

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
  PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.mapper.UserMapper">
  <insert id="insertUser" parameterType="com.example.model.User">
    INSERT INTO user (username, password)
    VALUES (#{username}, #{password})
  </insert>
</mapper>

@Service
public class UserService {
    @Autowired
    private UserMapper userMapper;

    public void addUser(User user) {
        userMapper.insertUser(user);
    }
}

@RestController
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserService userService;

    @PostMapping("/add")
    public String addUser(@RequestBody User user) {
        userService.addUser(user);
        return "User added successfully";
    }
}

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(50) NOT NULL,
  `password` varchar(50) NOT NULL,
  PRIMARY KEY (`id`)
) AUTO_INCREMENT=100;

public class User {
    private Integer id;
    private String username;
    private String password;
    // getters and setters
}