Mybatis

Mybatis

一、maven依赖

org.mybatis
mybatis
3.5.2
mysql
mysql-connector-java
5.1.47

二、配置mybatis-config.xml文件
在资源文件下创建properties文件
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis?useSSL=true&useUnicode=true&characterEncoding=utf8
username=root
password=123456
创建mybatis-config.xml

三、mybatis工具类 MybatisUtils

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 MybatisUtils {
private static SqlSessionFactory sqlSessionFactory;
static {
try {
String resource = “mybatis-config.xml”;
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
e.printStackTrace();
}
}
//获取SqlSession连接
public static SqlSession getSession(){
return sqlSessionFactory.openSession();
}
}

四、创建实体类（以User为例）

public class User {
private int id; //id
private String name; //姓名
private String pwd; //密码
//构造,有参,无参
//set/get
//toString()
}

五、编写mapper接口

import com.kuang.pojo.User;
import java.util.List;
public interface UserMapper {
List selectUser();
}

六、配置mapper.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“>

七、Unit测试类

public class MyTest {
@Test
public void selectUser() {
SqlSession session = MybatisUtils.getSession();
//方法一:
//List users = session.selectList(“com.kuang.mapper.UserMapper.selectUser”);
//方法二:
UserMapper mapper = session.getMapper(UserMapper.class);
List users = mapper.selectUser();
for (User user: users){
System.out.println(user);
}
session.close();
}
}

动态拼接和缓存都需要了解缓存去网上搜