MyBatis入门操作
MyBatis入门操作,其实是我只想验证一下instanceof
是否能在xml中使用
根据官网,下面我创建一个普通Maven项目,引入依赖:
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.7</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.49</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13.2</version>
</dependency>
resources/mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- 配置环境-->
<environments default="mysql">
<!--配置mysql的环境-->
<environment id="mysql">
<!--配置事务的类型-->
<transactionManager type="JDBC"></transactionManager>
<!--配置连接池-->
<dataSource type="POOLED">
<!--配置连接数据库的4个基本信息-->
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/test"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
<!--指定映射配置文件的位置,映射配置文件指的是每个dao独立的配置文件-->
<mappers>
<mapper resource="dao/test.xml"/>
</mappers>
</configuration>
resources/dao/test.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">
<!-- namespace:命名空间,用于隔离sql -->
<mapper namespace="test">
<select id="user" resultType="java.util.Map" parameterType="java.util.Map">
select * from user where
<if test="password instanceof java.util.List">
`password` in
<foreach collection="password" open="(" close=")" item="item" separator=",">
#{item}
</foreach>
</if>
<if test="!(password instanceof java.util.List)">
`password`=#{password}
</if>
</select>
</mapper>
测试代码
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class ListTest01 {
@Test
public void Test01() throws Exception {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
Map<String,Object> map=new HashMap<>();
List<String> list=new ArrayList<>(2);
list.add("2");
list.add("123");
map.put("password",list);
// map.put("password","2");
List<Object> objects = sqlSession.selectList("test.user",map);
System.out.println(objects);
}
}