插入一條記錄返回主鍵

• 情景：向資料庫中插入一條資料，要求返回插入資料的id
• 主鍵必須為整型，而且支援自增
• 需求實現:在儲存完成後執行SELECT LAST_INSERT_ID()即可

• 實體設計

public class User implements Serializable {
    private Integer id;
    private String name;
    private  String password;
    private Float salary;
    private Date birthday;

    public String getPassword
 
() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    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 Float getSalary() {
        return salary;
    }
    public void setSalary(Float salary) {
        this.salary = salary;
    }
    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(salary, user.salary) &&
                Objects.equals(birthday, user.birthday);
    }

    @Override
    public int hashCode() {

        return Objects.hash(id, name, salary, birthday);
    }

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

mapper介面

void saveUser(User user);

注意：需求每次插入需要返回該資料的id，當資料插入後，則當前物件的id屬性將會有值；介面設計不需要返回值
mapper對映檔案

<?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.bjlemon.mybatis.mapper.UserMapper">
    <cache type="org.mybatis.caches.ehcache.EhcacheCache"/>
     <insert id="saveUser"  parameterType="User">
         <selectKey keyProperty="id"  resultType="int" order="AFTER">
         SELECT LAST_INSERT_ID();
      </selectKey>
         INSERT INTO
                mybatis_in_action_user (name,password,salary,birthday)
         VALUES
                (#{name},#{password},#{salary},#{birthday})
     </insert>

</mapper>

ORCAL中實現

<insert parameterType="User" id="saveUser">

<selectKey order="BEFORE" resultType="int" keyProperty="id"> SELECT seq_mybatis_user.nextval FROM dual </selectKey>
INSERT INTO mybatis_user (user_id,user_name, password, salary, birthday) VALUES (#{id} ,#{name},#{password},#{salary},#{birthday}) 
</insert>

service層

  void addUser(User user);

  @Override
    public void addUser(User user) {
        SqlSession sqlSession = null;

        try {
            sqlSession = MybatisUtils.getSqlSession();
            UserMapper mapper = sqlSession.getMapper(UserMapper.class);
            if (user == null){
                throw  new IllegalArgumentException();
            }
            mapper.saveUser(user);
            sqlSession.commit();
        } catch (Exception e) {
            e.printStackTrace();
            sqlSession.rollback();
        } finally {
            MybatisUtils.clolseSqlSession();
        }

    }

測試方法

 @Before
    public  void before(){
         this.userService = new UserServiceImpl();
    }
    @Test
    public  void saveUser(){
         User user = new User();
         user.setName("小ad");
         user.setPassword("12312");
         user.setSalary(121.0F);
         user.setBirthday(new Date());
        this.userService.addUser(user);
        // 插入物件後 則這個物件的user就會有值
        System.out.println(user.getId());
    }