MyBatis 实现多对多中间表插入数据

<insert id="insert" useGeneratedKeys="true" keyProperty="user_id" keyColumn="user_id">
        insert into user
        (user_name,user_gender,user_email,user_phone,user_address,user_birthday,department_id)
        values(#{user_name},#{user_gender},#{user_email},#{user_phone},#{user_address},#{user_birthday},#{department_id})
    </insert>

<insert id="insertUserRole">
        insert into user_role values(#{user.user_id},#{role.role_id})
    </insert>

Date date = new Date();
        User user = new User("mike33", "male", "axxxx@163.com", "183xxxxxxxx", "chengdu", date, 1);
        Role role = new Role();
        role.setRole_id(4);
        //插入user
        service.insert(user);
        //打印user_id
        System.out.println("user_id----->>>>" + user.getUser_id());
        //插入中间表
        service.insertUserRole(user, role);

@Transactional(propagation=Propagation.REQUIRED,isolation=Isolation.READ_COMMITTED)
    public void insertUserRole(User user, Role role) {
        this.insert(user);
        mapper.insertUserRole(user, role);
    }

    public class Student implements Serializable {
        private Integer id;
        private String name;
        private Integer age;
        private String bir;
        private String phone;
        private String qq;
        private String attr;
        private String starts;
        private String mark;
        private Integer cityId;
        private Integer clazzId;
        private Integer groupId;
        private String cityName;
        private String clazzName;
        private String groupName;
        private List<Tag> tagList;
    }

public class Tag implements Serializable {
    private Integer id;
    private String name;
    private String type;
    private Date createtime;
}

<insert id="save" useGeneratedKeys="true" keyProperty="id" keyColumn="id" >
    insert into t_student(name, age, bir, phone, qq, attr, starts, mark, cityid, clazzid, groupid) values(#{name}, #{age}, #{bir},#{phone},#{qq},#{attr},#{starts},#{mark},#{cityId},#{clazzId},#{groupId})
</insert>
// useGeneratedKeys 是否以jdbc的方式将插入后的自增主键又返回个实体类
// keyProperty 实体类中对应的主键属性名
// keyCloumn 数据库中对应的主键属性名

<insert id="saveStudentTag" parameterType="com.lbw.ems.entity.Student">
        insert into t_student_tag(studentid, tagid) values
        <foreach collection="tagList" item="tag" separator=",">
            (#{id}, #{tag.id})
        </foreach>
    </insert>
// 因为此时我们需要当前的学生的Id,所以我们的参数类型还是一个Student类，在插入是，我们需要的是Student类中tagList集合中所有的id
所以使用了foreach标签
// foreach标签 遍历array、list、map(我只用过list)
// collection 填你想要遍历的集合在实体类中对应的属性名
// item 将每次遍历出来的对象取一个名字，不然不好取值，尤其是在两个实体类的字段名相同的时候，真的难顶
// sparator="," 每遍历一次后，在后面加上你所填的符