编写Mybatis代码,与spring不一样,不需要导入插件,只需导入架包即可;
在lib下 导入mybatis架包:mybatis-3.1.1.jar
mysql驱动架包:mysql-connector-java-5.1.6-bin.jar
在src目录下建立xml配置文件:conf.xml,是一些连接数据库的配置:
<?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:开发模式
work:工作模式
default="development",id="development",两个的属性值必须一致
-->
<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/mybatis"/>
<property name="username" value="root"/>
<property name="password" value="lxn123"/>
</dataSource>
</environment>
</environments> <!-- 在配置文件中 关联包下的 接口类-->
<mappers>
<mapper class="com.atguigu.mybatis.test3.UserMapper"/>
</mappers>
</configuration>
这是基于注解的方式,所以建立一个接口,在定义的方法上配置上应有的注解,注解中含有sql语句,需要提示的是这个接口不需要类去实现它
package com.atguigu.mybatis.test3; import java.util.List; import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update; import com.atguigu.mybatis.test.User; public interface UserMapper { /*
* 这是基于注解的映射方式,实现对数据的增删改查,将sql语句直接写在注解的括号中
* 这是一个接口,其不需要类去实现它
* 下边分别是插入,删除,修改,查询一个记录,查询所有的记录
* */ @Insert("insert into users(name,age) values(#{name},#{age})")
public void insertT(User user); @Delete("delete from users where id=#{id}")
public void deleteById(int id); @Update("update users set name=#{name},age=#{age} where id=#{id}")
public void updateT(User user); @Select("select * from users where id=#{id}")
public User getUser(int id); @Select("select * from users")
public List<User> getAllUsers();
}
封装列:User,这儿只写属性,getter和setter,tostring就不写了
private int id;
private String name;
private int age;
建立MybatisUtils类,有一个方法,加载mybatis和构建sqlSession
package com.atguigu.mybatis.test; import java.io.InputStream; import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class MybatisUtils {
public static SqlSessionFactory getFactory(){
String resource="conf.xml"; //加载mybatis 的配置文件(它也加载关联的映射文件)
InputStream is=MybatisUtils.class.getClassLoader().getResourceAsStream(resource); //构建sqlSession 的工厂
SqlSessionFactory factory=new SqlSessionFactoryBuilder().build(is);
return factory;
}
}
实现增删改查的方法
package com.atguigu.mybatis.test3; import java.util.List; import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.junit.Test; import com.atguigu.mybatis.test.MybatisUtils;
import com.atguigu.mybatis.test.User; public class UserMapperTest { @Test
//插入数据
public void testInsert(){
SqlSessionFactory factory=MybatisUtils.getFactory();
SqlSession session=factory.openSession(true);
//使用反射的方法
UserMapper mapper=session.getMapper(UserMapper.class);
mapper.insertT(new User(-1, "p", 4)); session.close();
} @Test
//删除数据
public void testDelete(){
SqlSessionFactory factory=MybatisUtils.getFactory();
SqlSession session=factory.openSession(true);
UserMapper mapper=session.getMapper(UserMapper.class);
mapper.deleteById(1);
session.close();
} @Test
//修改数据
public void testUpdate(){
SqlSessionFactory factory=MybatisUtils.getFactory();
SqlSession session=factory.openSession(true);
UserMapper mapper=session.getMapper(UserMapper.class);
mapper.updateT(new User(2, "jjjjj", 232));
session.close();
} @Test
//获取一条数据
public void testGetUser(){
SqlSessionFactory factory=MybatisUtils.getFactory();
SqlSession session=factory.openSession(true);
UserMapper mapper=session.getMapper(UserMapper.class);
User user=mapper.getUser(2);
session.close();
System.out.println(user);
} @Test
//获取所有数据
public void testGetAllUsers(){
SqlSessionFactory factory=MybatisUtils.getFactory();
SqlSession session=factory.openSession(true);
UserMapper mapper=session.getMapper(UserMapper.class);
List<User> users=mapper.getAllUsers(); session.close();
System.out.println(users);
}
}