useGeneratedKeys可以让mybatis获取生成的key keyProperty可以让mybatis将获取的key赋值给参数的指定字段

1、实体类User的书写

package com.yunhe.pojo;

import java.util.Date;
import java.util.Objects;

public class User {
    private Integer id;
    private String name;
    private Double sal;
    private Date birthday;

    public User() {
    }

    public User(Integer id, String name, Double sal, Date birthday) {
        this.id = id;
        this.name = name;
        this.sal = sal;
        this.birthday = birthday;
    }

    public User(String name, Double sal, Date birthday) {
        this.name = name;
        this.sal = sal;
        this.birthday = birthday;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Double getSal() {
        return sal;
    }

    public void setSal(Double sal) {
        this.sal = sal;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        User user = (User) o;
        return Objects.equals(id, user.id) && Objects.equals(name, user.name) && Objects.equals(sal, user.sal) && Objects.equals(birthday, user.birthday);
    }

    @Override
    public int hashCode() {
        return Objects.hash(id, name, sal, birthday);
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", sal=" + sal +
                ", birthday=" + birthday +
                '}';
    }
}

2、UserMapper接口的书写

public interface UserMapper {
    // 插入数据
    Integer insert(User user);
}

3、UserMapper.xml的书写

    <insert id="insert" useGeneratedKeys="true" keyProperty="id">
        insert into t_user(`name`,sal,birthday) values (#{name},#{sal},#{birthday})
    </insert>

4、测试类书写

public class Test {
    public static void main(String[] args) {

        SqlSessionFactory sqlSessionFactory = MybatisUtil.getSqlSessionFactory();

        SqlSession session = sqlSessionFactory.openSession();

        UserMapper mapper = session.getMapper(UserMapper.class);
        User user = new User("李四", 200.0, new Date());
        Integer i = mapper.insert(user);
        System.out.println(user.getId());
        session.commit();
    }
}