例如班级表(Clazz)-和学生表(Student)的关系是一对多的关系,我们希望在加载一个班级的时候,能自动加载这个班级下的学生列表。
Java实体类如下(学生实体类省略):
@TableName("t_class")
public class Clazz implements Serializable {
@TableId
private Long id;
private Date createDate;//
private Date updateDate;
private String name;//班级名称
private List<Student> students;
}
Mapper.xml:
<?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.terrynow.test.mapper.ClazzMapper">
<select id="selectClazzById" parameterType="int" resultMap="clazzResultMap">
select * from t_clazz where id = #{id}
</select>
<resultMap type="com.terrynow.test.pojo.Clazz" id="clazzResultMap">
<id property="id" column="id"/>
<result property="name" column="name"/>
<collection property="students" ofType="com.terrynow.test.pojo.Student"
column="id" javaType="ArrayList">
<id property="id" column="id"/>
<result property="name" column="name"/>
<result property="sex" column="sex"/>
<result property="age" column="age"/>
</collection>
</resultMap>
</mapper>
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