Table of Contents

  1. 什么是 MyBatis ?
    1. MyBatis github
    2. MyBatis 文档
  2. 入门程序
    1. 项目结构:
    2. 各文件介绍:

MyBatis 是支持定制化 SQL、存储过程以及高级映射的优秀的持久层框架。

什么是 MyBatis ?

MyBatis 是支持定制化 SQL、存储过程以及高级映射的优秀的持久层框架。

MyBatis github

https://github.com/mybatis/mybatis-3

MyBatis 文档

http://mybatis.github.io/mybatis-3/zh/index.html

入门程序

想要使用 MyBatis 只需将 mybatis-x.x.x.jar 文件置于 classpath 中。
如果使用 Maven 构建项目,则需将下面的 dependency 置于 pom.xml 中:

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<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.8.2</version>
</dependency>

我选择第二种,在Eclipse中新建一个maven项目

项目结构:

项目结构

各文件介绍:

  • pom文件:由于使用了mySQL数据库,这里还依赖了一个mySQL驱动包
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<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>Mybatis</groupId>
<artifactId>Mybatis</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.2.8</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.34</version>
</dependency>
</dependencies>
</project>
  • 实体类User :
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package com.mybatis.domain;
public class User {
private String name;
private Integer age;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
  • UserMapper接口:
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package com.mybatis.mapper;
import com.mybatis.domain.User;
public interface UserMapper {
public User findById(String Id);
}
  • UserMapper接口的实现,userMapper.xml:
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<?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"> <!--相当于UserMapper接口的实现 namespace必须是UserMapper类路径-->
<mapper namespace="com.mybatis.mapper.UserMapper">
<!-- findById必须和接口中的方法名一样 返回一个User-->
<select id="findById" parameterType="String"
resultType="com.mybatis.domain.User">
select * from user where id=#{id}
</select>
</mapper>
  • 数据源配置 configuration.xml
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<?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>
<!--数据源配置 -->
<environments default="development">
<environment id="development">
<transactionManager type="jdbc" />
<dataSource type="POOLED">
<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> <mappers>
<!--userMapper.xml装载进来 -->
<mapper resource="userMapper.xml" />
</mappers>
</configuration>
  • 测试类MyBatisTest:
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package com.mybatis.test;
import com.mybatis.domain.User;
import com.mybatis.mapper.UserMapper;
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;
public class MyBatisTest {
/** * MyBatis SqlSessionFactory * SqlSessionFactory????SqlSession????????????SqlSession??????????commit?rollback?close???? * @return */ private static SqlSessionFactory getSessionFactory() {
SqlSessionFactory sessionFactory = null;
String resource = "configuration.xml";
try {
sessionFactory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsReader(
resource));
} catch (IOException e) {
e.printStackTrace();
}
return sessionFactory;
}
public static void main(String[] args) {
SqlSession sqlSession = getSessionFactory().openSession();
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
User user = userMapper.findById("1");
System.out.println(user.getName());
}
}

数据库中插入条数据:
id=”1” name=”wn” age=”23”

运行测试类,在控制台看到结果:wn