MyBatis基础入门

爱被打了一巴掌 2022-11-21 00:59 203阅读 0赞

1、jar包引入

<dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.6</version>
    </dependency>

2、核心配置文件

a、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>
        
    	<properties resource="db.properties" />
    	
     	<settings>
    	
    		
    		<setting name="mapUnderscoreToCamelCase" value="true" />
    
    				
    		 
    	  <setting name="aggressiveLazyLoading" value="false" />
    
    	</settings>
    
    	
    
    	<typeAliases>
    		<package name="com.enjoylearning.mybatis.entity" />
    	</typeAliases>
    
    
    	
    	<environments default="development">
    		
    		<environment id="development">
    			<transactionManager type="JDBC" />
    			<dataSource type="UNPOOLED">
    				<property name="driver" value="${jdbc_driver}" />
    				<property name="url" value="${jdbc_url}" />
    				<property name="username" value="${jdbc_username}" />
    				<property name="password" value="${jdbc_password}" />
    			</dataSource>
    		</environment>
    
    
    	</environments>
    
    	
    	<mappers>
    		
    		<mapper resource="sqlmapper/TUserMapper.xml" />
    		<mapper resource="sqlmapper/TUserTestMapper.xml" />
    		<mapper resource="sqlmapper/TRoleMapper.xml" />
    		<mapper resource="sqlmapper/TJobHistoryMapper.xml" />
    		<mapper resource="sqlmapper/TPositionMapper.xml" />
    		<mapper resource="sqlmapper/THealthReportFemaleMapper.xml" />
    		<mapper resource="sqlmapper/THealthReportMaleMapper.xml" />
    
    	</mappers>
    
    
    
    
    </configuration>

b、db.properties

jdbc_driver=com.mysql.jdbc.Driver
    jdbc_url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf8&allowMultiQueries=true
    jdbc_username=root
    jdbc_password=lixun033
    project_src =src/main/java
    project_mapper_xml =src/main/resources/sqlmapper
    #class_path=C:/Users/admin/.m2/repository/mysql/mysql-connector-java/5.1.18/mysql-connector-java-5.1.18.jar
    class_path=D:/devTools/LocalRepository/mysql/mysql-connector-java/5.1.18/mysql-connector-java-5.1.18.jar

c、TUserTestMapper.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.enjoylearning.mybatis.mapper.TUserTestMapper">
    
    
    	<select id="selectByPrimaryKey" resultType="TUser">
    		select
    		id, user_name, real_name, sex, mobile, email, note
    		from t_user_test
    		where id = #{id,jdbcType=INTEGER}
    	</select>
    	
    	<select id="selectAll" resultType="TUser">
    		select
    		id, user_name, real_name, sex, mobile, email, note
    		from t_user_test
    	</select>
    
    
    </mapper>

3、java代码

a、dao接口

package com.enjoylearning.mybatis.mapper;
    
    import java.util.List;
    import java.util.Map;
    import com.enjoylearning.mybatis.entity.TUser;
    
    public interface TUserTestMapper {
    	
    	TUser selectByPrimaryKey(Integer id);
    	
    	
    	List<TUser> selectAll();
    
    }

b、测试代码

@BeforeTUserTestMapper
    	public void init() throws IOException {
    		//--------------------第一阶段---------------------------
    	    // 1.读取mybatis配置文件创SqlSessionFactory
    		String resource = "mybatis-config.xml";
    		InputStream inputStream = Resources.getResourceAsStream(resource);
    		// 1.读取mybatis配置文件创SqlSessionFactory
    		sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    		inputStream.close();
    	}
    @Test
    	//知识点：resultType
    	public void testAutoMapping() throws IOException {
    		// 2.获取sqlSession	
    		SqlSession sqlSession = sqlSessionFactory.openSession();
    		// 3.获取对应mapper
    		TUserTestMapper mapper = sqlSession.getMapper(TUserTestMapper.class);
    		// 4.执行查询语句并返回多条数据
    		List<TUser> users = mapper.selectAll();
    		for (TUser tUser : users) {
    			System.out.println(tUser);
    		}
    	}

a、javabean

b、dao

c、mapping配置文件

d、test代码