MyBatis中，查询结果有ListString下的collection标签 场景：有两张表学⽣表(student)、班级表(class)学⽣表字段：学⽣姓名（sname）+班级编号（cid）班级表字段：班级名称(cname)+班级编号(cid)需求：查询三年级所有学⽣，查询结果班级名称+学⽣姓名 select c.cname,s.sname from class c left join ...
public class Test { public static void main(String[] args) throws IOException { try (InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml")) { // 构建session工厂 DefaultSqlSessionFactory SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputS...
import com.hnpicheng.mybatisissue.domain.People; import com.hnpicheng.mybatisissue.mapper.PeopleMapper; public class App { public static void main( String[] args ) { ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring-mybatis.xml"); PeopleMapper peopleMapper = conte...
第二种:list里的元素是string字符串<if test="studentIds!=null and studentIds.size>0"> case when a.id in <foreach collection="studentIds" index="index" item="item" open="(" separator="," close=")"> '${item}' </foreach> then 1 else 2 end , </if> 总结: # 是起的占位符的...
private String short_name; private Integer city_id; private List<GoodsImage> imageList; // 问题选项 *** 问题表里不需要有这个属性对应的字段 private String image; }//问题选项 实体类 public class GoodsImage { private Integer id; private String image_url; ...
mybatis里的sql中按collection拼接查询语句,字符串类型的collection的写法有区别,第一种:list里的元素不是string字符串,而是一个实体类<iftest="studentList!=nullandstudentList.size>0">anda.idin<foreachcollection="studentList"index="index"item="item"open="("s.
List<Map> allList(@Param("typeList") List<String> typeList); MyBatis层: <resultMap id="child" type="java.util.Map"><result property="activityName"column="activity_name"/><collection property="child" ofType="java.util.Map" javaType="ArrayList" resultMap="child2"></collection></resultMap...
@Data //班级类 public class Class { private String id; private String name; private List<Student> students;//---重点在这里,一个班级对应多个学生 } 代码语言:javascript 代码运行次数:0 运行 AI代码解释 @Data public class Student { private int id; private String name; private int age; } - ...
上面的参数都是List,如果是String[]这种的就是把collection 的值改为array,如下demo 四、批量删除 代码语言:javascript 代码运行次数:0 运行 AI代码解释 <deleteid="getArticleList"parameterType="String">DEKETEfrom blog_article a where a.article_idin<foreach collection="array"index="index"item="item"open...
mybatis xml中collection用法mybatis xml中collection用法 在MyBatis的XML映射文件中,可以使用collection元素来定义对集合属性的映射。 collection元素用于映射一个JavaBean的集合属性,假设JavaBean中有一个名为list的集合属性,例如: ```java public class User { private Integer id; private String username; private ...