文章目录
-
-
- 1.如何获得MyBatis:
- 2.第一个Mybatis程序
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- 2.1 搭建数据库
- 2.2 新建项目:导入maven依赖
- 2.3 编写mybatis的核心配置文件
- 2.4 编写mybatis工具类
- 2.5 编写代码
- 2.6 测试
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1.如何获得MyBatis:
- maven仓库地址:https://mvnrepository.com/artifact/org.mybatis/mybatis/3.5.2
- Github上源码:https://github.com/mybatis/mybatis-3/releases
- 中文文档:https://mybatis.org/mybatis-3/zh/index.html
2.第一个Mybatis程序
思路:搭建环境–》导入Mybatis–》编写代码–》测试
2.1 搭建数据库
USE mybatis;
CREATE TABLE USER(
id INT NOT NULL PRIMARY KEY,
NAME VARCHAR(32) DEFAULT NULL,
pwd VARCHAR(32) DEFAULT NULL
) ENGINE=INNODB DEFAULT CHARSET=utf8;
INSERT INTO USER(id,NAME,pwd) VALUES
(1,'狂神','123'),
(2,'张三','123'),
(3,'李四','123')
2.2 新建项目:导入maven依赖
- 新建一个普通项目
- 删除src文件,可以将这个项目作为父工程,以便创建子工程
- 导入maven依赖
<dependencies>
<!--mysql驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.15</version>
</dependency>
<!--mybatis驱动-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.2</version>
</dependency>
<!--junit驱动-->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>true</filtering>
</resource>
</resources>
</build>
2.3 编写mybatis的核心配置文件
创建一个模块
<!--核心配置文件-->
<configuration>
<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?
useSSL&useUnicode=true&characterEncoding=UTF-8"/>
<property name="username" value="root"/>
<property name="password" value="123"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="org/mybatis/example/BlogMapper.xml"/>
</mappers>
</configuration>
2.4 编写mybatis工具类
package com.kuang.dao;
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 javax.annotation.Resource;
import java.io.IOException;
import java.io.InputStream;
//sqlSessionFactory--->sqlSession对象(生产)
public class MyBatisUtils {
private SqlSessionFactory sqlSessionFactory;
static{
try {
//第一步:获取sqlSessionFactory对象
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
e.printStackTrace();
}
}
//既然有了 SqlSessionFactory,顾名思义,我们就可以从中获得 SqlSession 的实例了。
//SqlSession 完全包含了面向数据库执行 SQL 命令所需的所有方法。
public static SqlSession getSqlSession(){
return sqlSessionFactory.openSession();
}
}
2.5 编写代码
实体类:User.java
package com.kuang.pojo;
public class User {
private int id;
private String name;
private String pwd;
public User() {}
public int getId() {
return id;
}
public String getName() {
return name;
}
public String getPwd() {
return pwd;
}
public void setId(int id) {
this.id = id;
}
public void setName(String name) {
this.name = name;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + '\'' +
", pwd='" + pwd + '\'' +
'}';
}
}
Dao接口:UserDao
//操作数据库的实体类
public interface UserDao {
//返回所有的用户
List<User> getUserList();
}
接口实现类: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">
<!--namespace=绑定一个Dao/Mapper接口-->
<!--让这个配置文件和UserDao接口绑定-->
<mapper namespace="com.kuang.dao.UserDao">
<!--查询语句-->
<select id="getUserList" resultType="com.kuang.pojo.User" >
select * from mybatis.user;
</select>
</mapper>
2.6 测试
package com.kuang.dao;
import com.kuang.pojo.User;
import com.kuang.utils.MyBatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.List;
public class UserDaoTest {
@Test
public void test(){
//获取sqlSession对象
SqlSession sqlSession = MyBatisUtils.getSqlSession();
//方式一:getMapper
UserDao mapper = sqlSession.getMapper(UserDao.class);
List<User> userList = mapper.getUserList();
//方式二:不推荐
User ouserlist1= (User)sqlSession.selectList("com.kuang.dao.UserDao.getUserList");
for(User user:userList){
System.out.println(user);
}
//关闭sqlSession
sqlSession.close();
}
}