一、新建maven项目，方便框架导入
1. 在pom文件中添加依赖
<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.6</version>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.13</version>
</dependency>
<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13-beta-1</version>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-core -->
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.11.1</version>
</dependency> |
2. 导入改变 （Import Changes)
二、在resource文件夹下创建配置文件
0. 日志配置文件
log4j.rootLogger=DEBUG, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d - %c -%-4r [%t] %-5p %c %x - %m%n
|
1. 新建数据库配置文件db.properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/book?serverTimezone=UTC&useUnicode=true&characterEncoding=utf8
jdbc.username=root
jdbc.password= |
2.新建Mybatis配置文件mybatis-config.xml
1.导入数据库连接配置
<!-- 导入数据库连接配置 -->
<properties resource="db.properties"></properties>
|
2.定义数据源
设置事务管理器为JDBC，连接源类型为连接池，并且设置引用数据库连接配置中的变量
<!-- 定义数据源 -->
<environments default="development">
<environment id="development">
<!--配置事务管理器-->
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<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> |
3.设置映射文件的配置
在package的name属性中指明mapper.xml文件所在的路径
<!-- 设置映射文件的包 -->
<mappers>
<package name="io.github.coinsjack.mapper"></package>
</mapper |
三、测试使用
项目结构,这里需要注意,如果想要将xml文件和java文件分离,就需要在recourse和java目录下建立相同的mapper目录结构,java里面写interface而resources里面写xml文件
1. pojo中创建我们的实体类Board
package io.github.coinsjack.pojo;
public class Board {
private String user;
private String time;
private String message;
public Board() {
}
public Board(String user, String time, String message) {
this.user = user;
this.time = time;
this.message = message;
}
public void setUser(String user) {
this.user = user;
}
public void setTime(String time) {
this.time = time;
}
public void setMessage(String message) {
this.message = message;
}
@Override
public String toString() {
return "Board{" +
"user='" + user + '\'' +
", time='" + time + '\'' +
", message='" + message + '\'' +
'}';
}
} |
2.编写接口BoardMapper 假设在这里我们随便取出一条记录
package io.github.coinsjack.dao;
import io.github.coinsjack.pojo.Board;
public interface BoardMapper {
Board selectBoard();
} |
3.编写mapper.xml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="io.github.coinsjack.dao.BoardMapper">
<select id="selectBoard" resultType="io.github.coinsjack.pojo.Board">
SELECT * FROM board LIMIT 1;
</select>
</mapper> |
这里需要注意,将namespace指向对应的mapper接口类型, 而select标签中的id属性应当和接口中的方法名一致
4.编写工具类MyBatisUtil.java
1.准备好mybatis配置文件的路径名,可以从resource往下写
2.配置文件->InputStream->SqlSessionFactory->SqlSession
3.SqlSession就是我们想要的,通过它来获取Mapper
package io.github.coinsjack.util;
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;
public class MyBatisUtil {
private static SqlSessionFactory sqlSessionFactory = null;
static {
try {
InputStream in = Resources.getResourceAsStream("mybatis-config.xml");
sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
} catch (IOException e) {
e.printStackTrace();
}
}
public static SqlSession getSqlSession() {
return sqlSessionFactory.openSession();
}
} |
5.编写测试类BoardMapperTest
package io.github.coinsjack.dao;
import io.github.coinsjack.util.MyBatisUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
public class BoardMapperTest {
@Test
public void testSelectBoard() {
SqlSession sqlSession = MyBatisUtil.getSqlSession();
BoardMapper boardMapper = sqlSession.getMapper(BoardMapper.class);
System.out.println(boardMapper.selectBoard());
}
} |
到这里我们就可以访问到数据库中记录了
