Mybatis传入参数类型为List作为条件进行查询
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2017.02.07 10:23:16字数 130阅读 5,658
表结构:
表名称为constant
需求:
现在想查询type为2、3的所有数据(甚至想查询type为1,2,3,4,5....,100的所有数据)并且返回的值是Map(key为id,value为constant类)
如果采用一个一个传参的方式进行查询肯定是不行的,以下是通过Mybatis提供的foreach标签并配合in进行查询
Mapper:
<?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.jm.dao.ConstantDao"><resultMap id="BaseResultMap" type="com.jm.model.Constant"><result column="id" property="id" jdbcType="BIGINT" /><result column="key" property="key" jdbcType="VARCHAR" /><result column="value" property="value" jdbcType="VARCHAR" /><result column="type" property="type" jdbcType="INTEGER" /></resultMap><!--此处一定要注意属性的名称是resultMap,并且值为“BaseResultMap”这样就可以保证返回的Map的value是Constant的对象 --><select id="loadConstantByType" resultMap="BaseResultMap">select * from constant where type in<!-- 这里要将collection属性的值标记为list,不然不知道传入的参数是list separator表示分离器 item表示list中的一个元素 --><foreach item="item" index="index" collection="list" open="("separator="," close=")">#{item}</foreach></select></mapper>
DAO:
import java.util.List;
import java.util.Map;import org.apache.ibatis.annotations.MapKey;
import org.springframework.stereotype.Repository;@Repository
public interface ConstantDao {/*** 注释@MapKey表示表中那个字段作为Map的key* @return*/@MapKey("id")Map<Long,Constant> loadConstantByType(List<Integer> type);
}
POJO实体类:
public class Constant {private Long id;private String key;private String value;private Integer type;public String toString(){StringBuffer s = new StringBuffer("Constant:{");s.append("id:").append(this.id).append(",");s.append("key:").append(this.key).append(",");s.append("value:").append(this.value).append(",");s.append("type:").append(this.type).append("}");return s.toString();}public Constant() {super();// TODO Auto-generated constructor stub}public Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getKey() {return key;}public void setKey(String key) {this.key = key == null ? null : key.trim();}public String getValue() {return value;}public void setValue(String value) {this.value = value == null ? null : value.trim();}public Integer getType() {return type;}public void setType(Integer type) {this.type = type;}
}
pojo中的实体类最好重写toString方法
junitTest:
import java.util.Arrays;
import java.util.List;
import java.util.Map;import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { "classpath:spring.xml", "classpath:spring-mybatis.xml" })
public class MubatisMapTest {@Autowiredprivate ConstantDao constantDao;@Testpublic void mapTest1() {List<Integer> typeList = Arrays.asList(2,3);Map<Long,Constant> constantMap = constantDao.loadConstantByType(typeList);System.out.println(constantMap);}
}
最终测试结果:
Paste_Image.png