1、搭建实验数据库
CREATE DATABASE mybatis;
USE mybatis;
DROP TABLE IF EXISTS user;
CREATE TABLE user (
id int(20) NOT NULL,
name varchar(30) DEFAULT NULL,
pwd varchar(30) DEFAULT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
insert into user(id,name,pwd) values (1,'白白','123456'),(2,'张三','abcdef'),(3,'李四','987654');
2、导入MyBatis相关 jar 包
<dependencies>
<!--spring框架-->
<dependency>
<groupid>org.springframework</groupid>
<artifactid>spring-webmvc</artifactid>
<version>5.1.10.RELEASE</version>
</dependency>
<!--mybatis框架-->
<dependency>
<groupid>org.mybatis</groupid>
<artifactid>mybatis</artifactid>
<version>3.5.2</version>
</dependency>
<!-- mysql启动-->
<dependency>
<groupid>mysql</groupid>
<artifactid>mysql-connector-java</artifactid>
<version>8.0.30</version>
</dependency>
</dependencies>
3、编写MyBatis核心配置文件
<?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>
<typealiases>
<package name="com.bai.pojo">
</package></typealiases>
<environments default="development">
<environment id="development">
<transactionmanager type="JDBC">
<datasource type="POOLED">
<property name="driver" value="com.mysql.cj.jdbc.Driver">
<property name="url" value="jdbc:mysql://localhost:3306/mybatis">
<property name="username" value="root">
<property name="password" value="root">
</property></property></property></property></datasource>
</transactionmanager></environment>
</environments>
<mappers>
<package name="com.bai.dao">
</package></mappers>
</configuration>
4、编写MyBatis工具类
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();
}
}
5、创建实体类
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()
}
6、编写Mapper接口类
import com.bai.pojo.User;
import java.util.List;
public interface UserMapper {
List<user> selectUser();
}
</user>
7、编写Mapper.xml配置文件
- namespace 十分重要，不能写错！是接口全类名
<?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.kuang.dao.UserMapper">
<select id="selectUser" resulttype="com.kuang.pojo.User">
select * from user
</select>
</mapper>
8、编写测试类
public class MyTest {
@Test
public void selectUser() {
SqlSession session = MybatisUtils.getSession();
//方法一:
//List<user> users = session.selectList("com.kuang.mapper.UserMapper.selectUser");
//方法二:
UserMapper mapper = session.getMapper(UserMapper.class);
List<user> users = mapper.selectUser();
for (User user: users){
System.out.println(user);
}
session.close();
}
}
</user></user>
9、运行测试，成功的查询出来的我们的数据，ok！
BindingException: Invalid bound statement (not found):
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>
Original: https://www.cnblogs.com/b10100912/p/16661752.html
Author: 面向CV工程师
Title: 快速上手Mybatis项目
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