工程目录结构
引入mybatis库和数据库链接驱动
<?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.test</ groupId>
< artifactId> mybatis-demo</ artifactId>
< version> 1.0-SNAPSHOT</ version>
< dependencies>
< dependency>
< groupId> org.mybatis</ groupId>
< artifactId> mybatis</ artifactId>
< version> 3.5.1</ version>
</ dependency>
< dependency>
< groupId> mysql</ groupId>
< artifactId> mysql-connector-java</ artifactId>
< version> 5.1.47</ version>
</ dependency>
< dependency>
< groupId> junit</ groupId>
< artifactId> junit</ artifactId>
< version> 4.12</ version>
</ dependency>
</ dependencies>
</ project>
创建数据库用户表
create database test default charset = utf8;
create table user (
id int ( 11 ) primary key auto_increment ,
name varchar ( 20 ) ,
age int ( 2 )
) engine = InnoDB default charset = utf8;
创建实体类
public class User {
private Integer id;
private String name;
private Integer age;
}
创建对象关系映射文件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.test.quickstart.mapper.UserMapper" >
< select id = " selectById" parameterType = " int" resultType = " User" >
select * from user where id = #{id}
</ select>
</ mapper>
创建配置文件mybatis-config.xml
<?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>
< settings>
< setting name = " mapUnderscoreToCamelCase" value = " true" />
< setting name = " logImpl" value = " STDOUT_LOGGING" />
</ settings>
< typeAliases>
< typeAlias type = " com.test.quickstart.bean.User" alias = " User" />
</ typeAliases>
< environments default = " jd" >
< environment id = " jd" >
< 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 = " root" />
</ dataSource>
</ environment>
</ environments>
< mappers>
< mapper resource = " mapper/UserMapper.xml" />
</ mappers>
</ configuration>
创建UserMapper.java
@Mapper
public interface UserMapper {
User selectById ( Integer id) ;
}
测试
public class Demo01Test {
private SqlSessionFactory sessionFactory;
@Before
public void before ( ) throws IOException {
InputStream is = Resources. getResourceAsStream ( "mybatis-config.xml" ) ;
sessionFactory = new SqlSessionFactoryBuilder ( ) . build ( is) ;
}
@Test
public void testSelect ( ) {
SqlSession session = sessionFactory. openSession ( ) ;
UserMapper userMapper = session. getMapper ( UserMapper. class ) ;
User user = userMapper. selectById ( 1111 ) ;
System. out. println ( user) ;
session. close ( ) ;
}