mybatis框架快速入门
通过快速入门示例，我们发现使用mybatis 是非常容易的一件事情，因为只需要编写 Dao 接口并且按照
mybatis要求编写两个配置文件，就可以实现功能。远比我们之前的jdbc方便多了。（我们使用注解之后，将变得
更为简单，只需要编写一个mybatis配置文件就够了。）
1.mybatis的环境搭建
第一步：创建maven工程并导入坐标
第二步：创建实体类和dao的接口
第三步：创建Mybatis的主配置文件 SqlMapConifg.xml
第四步：创建映射配置文件 IUserDao.xml
- 创建maven工厂并导入坐标
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.itheima</groupId>
<artifactId>mybatis_eesy_day01_quickstart</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>mybatis_eesy_day01_quickstart</name>
<!-- FIXME change it to the project‘s website -->
<url>http://www.example.com</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.5</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
<plugins>
<!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
<!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
<plugin>
<artifactId>maven-site-plugin</artifactId>
<version>3.7.1</version>
</plugin>
<plugin>
<artifactId>maven-project-info-reports-plugin</artifactId>
<version>3.0.0</version>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>- 创建实体类和dao接口
public class User implements Serializable {
private Integer id;
private String username;
private Date birthday;
private String address;
private String sex;public interface IUserDao {
// 查询所有用户
List<User> findAll();
}- 创建主配置文件
<?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>
<!--配置mybatis的环境-->
<environments default="mysql">
<!--配置mysql的环境-->
<environment id="mysql">
<!--配置事务的类型-->
<transactionManager type="JDBC"></transactionManager>
<!--配置数据库的信息，用的是数据源（连接池技术）-->
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/eesy_mybatis"/>
<property name="username" value="root"/>
<property name="password" value="123"/>
</dataSource>
</environment>
</environments>
<!--告知mybatis映射文件的位置-->
<mappers>
<mapper resource="com/itheima/dao/IUserDao.xml"/>
</mappers>
</configuration>- 创建映射文件
<?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.itheima.dao.IUserDao">
<select id="findAll" resultType="com.itheima.domain.User">
SELECT * FROM user
</select>
</mapper>编写测试代码
package com.itheima;
import com.itheima.dao.IUserDao;
import com.itheima.domain.User;
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;
import java.util.List;
public class TestMybatis {
public static void main(String[] args) throws IOException {
//1.读取配置文件
InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
//2.创建SqlSessionFactory的构建者对象
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
//3.使用构建者创建工厂对象SqlSessionFactory
SqlSessionFactory factory = builder.build(in);
//4.使用SqlSessionFactory创建SqlSession对象
SqlSession sqlSession = factory.openSession();
//5.使用SqlSession创建dao的代理对象
IUserDao userDao = sqlSession.getMapper(IUserDao.class);
//6.使用代理对象执行查询方法
List<User> userList = userDao.findAll();
for (User user :userList){
System.out.println(user.toString());
}
//7.释放资源
sqlSession.close();
in.close();
}
}测试结果
User{id=41, username=‘老王‘, birthday=Tue Feb 27 17:47:08 CST 2018, address=‘北京‘, sex=‘男‘}
User{id=42, username=‘小二王‘, birthday=Fri Mar 02 15:09:37 CST 2018, address=‘北京金燕龙‘, sex=‘女‘}
User{id=43, username=‘小二王‘, birthday=Sun Mar 04 11:34:34 CST 2018, address=‘北京金燕龙‘, sex=‘女‘}
User{id=45, username=‘传智播客‘, birthday=Sun Mar 04 12:04:06 CST 2018, address=‘北京金燕龙‘, sex=‘男‘}
User{id=46, username=‘老王‘, birthday=Wed Mar 07 17:37:26 CST 2018, address=‘北京‘, sex=‘男‘}
User{id=48, username=‘小马宝莉‘, birthday=Thu Mar 08 11:44:00 CST 2018, address=‘北京修正‘, sex=‘女‘}