Mybatis
项目结构
一：导包
https://mvnrepository.com/artifact/org.mybatis/mybatis
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.3</version>
</dependency>
二：mybatis配置文件
mybatis-configure.xml (主要配置文件)
<?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>
<!--引入数据库配置数据源-->
<properties resource="db.properties"></properties>
<!--Log4j日志实现-->
<settings>
<setting name="logImpl" value="LOG4J"/>
</settings>
<!--扫描POJO包下所有类，起别名-->
<typeAliases>
<package name="com.skeleton.pojo"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${user}"/>
<property name="password" value="${pwd}"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/skeleton/mapper/UserMapper.xml"/>
</mappers>
</configuration>
</configuration>
db.properties （数据库数据源配置）
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/ykhl?useSSL=false&serverTimezone=UTC&characterEncoding=UTF-8
user=root
pwd = skeletonmysql
log4j.properties （日志实现）
### 设置###
log4j.rootLogger = debug,stdout
### 输出信息到控制抬 ###
log4j.appender.stdout = org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target = System.out
log4j.appender.stdout.layout = org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern = [%p]: %c{3}(%c{1}.java:%L)\t\t %m%n
三：编写 实体类接口
- UserMapper.java
package com.skeleton.mapper;
import com.skeleton.pojo.User;
import java.util.List;
/**
* @Author: KL-Skeleton
* @Description:
* @Date: Created in 21:49 2020/8/15
*/
public interface UserMapper {
List<User> getUserByList();
}
四：编写 实体类接口的Mapper配置文件
- UserMapper.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.skeleton.mapper.UserMapper">
<select id="getUserByList" resultType="user" >
select * from ykhl.yk_chati_user
</select>
</mapper>
五：编写 mybatis 工具类
package com.skeleton.mybatis;
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 java.io.IOException;
import java.io.InputStream;
/**
* @Author: KL-Skeleton
* @Description:
* @Date: Created in 22:00 2020/8/14
*/
public class MybatisUtil<T> {
//配置文件
private static String resource = "mybatis-configure.xml";
//SqlSessionFactory工厂
private static SqlSessionFactory sqlSessionFactory;
static {
//静态代码块，创建sqlSessionFactory对象
try {
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
e.printStackTrace();
}
}
//获取sqlsession
public static SqlSession getSqlSeetion() {
return sqlSessionFactory.openSession();
}
public static <T> void openSession(Class<T> tClass,OpenSessionLisener<T> openSessionLisener){
try(SqlSession sqlSession = getSqlSeetion()) {
openSessionLisener.run(sqlSession.getMapper(tClass));
sqlSession.commit();
}
}
public interface OpenSessionLisener<T>{
void run(T t);
}
}
六：从工具类获取 Sqlsession 执行业务逻辑
使用junit实现单元测试
@Test
public void mybatis(){
//方法一
MybatisUtil.openSession(UserMapper.class, user -> {
for (User user1 : user.getUserByList()) {
System.out.println(user1);
}
});
//方法二
try (SqlSession sqlSession = MybatisUtil.getSqlSeetion()){
UserMapper userMapper =sqlSession.getMapper(UserMapper.class);
for (User user1 : userMapper.getUserByList()) {
System.out.println(user1);
}
}
}
结果