一个最小mybatis

项目结构

package hello;

import java.io.IOException;
import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class App
{
    public static void main( String[] args ) throws IOException
    {
    	String resource = "hello/config.xml";
    	InputStream inputStream = Resources.getResourceAsStream(resource);
    	SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    	SqlSession session = sqlSessionFactory.openSession();
    	User user = (User)session.selectOne("hello.UserMapper.selectOne");
    	System.out.println(user.getName());
    }
}

实体类

package hello;

public class User
{
	private String name;
	private int age;

	public String getName()
	{
		return name;
	}

	public void setName(String name)
	{
		this.name = name;
	}

	public int getAge()
	{
		return age;
	}

	public void setAge(int age)
	{
		this.age = age;
	}

}

　　

<?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>
	<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/boot" />
				<property name="username" value="root" />
				<property name="password" value="123456" />
			</dataSource>
		</environment>
	</environments>
	<mappers>
		<mapper resource="hello/UserMapper.xml" />
	</mappers>
</configuration>

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="hello.UserMapper">
	<select id="selectOne" resultType="hello.User">
		select * from user;
	</select>
</mapper>

pom

<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>test.demo</groupId>
	<artifactId>mybatis</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>mybatis</name>
	<url>http://maven.apache.org</url>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	</properties>

	<dependencies>
		<!-- mybatis -->
		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis</artifactId>
			<version>3.2.3</version>
		</dependency>
		<!-- mysql -->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.1.38</version>
		</dependency>
	</dependencies>
</project>

首先以流的信息将数据库连接信息读取进来，生成到数据库的连接(SqlSession)

String resource = "hello/config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);

 SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
 SqlSession session = sqlSessionFactory.openSession();

进行数据库操作

    	User user = (User)session.selectOne("hello.UserMapper.selectOne");
    	System.out.println(user.getName());