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);

    }
}

在这里插入图片描述

posted @ 2022-09-16 00:08  凌康  阅读(19)  评论(0编辑  收藏  举报