首页 > 其他 > 详细

Mybatis建立连接

时间:2020-07-29 22:19:59      阅读:72      评论:0      收藏:0      [点我收藏+]

maven 仓库:

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.46</version>
</dependency>

<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.2</version>
</dependency>

<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>

1.首先编写 Mabatis工具类:

package com.wang.utils;

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.InputStream;

public class MybatisUtils {
private static SqlSessionFactory sqlSessionFactory;
static {
try {
String resource="mybatis-config.xml";
InputStream is = Resources.getResourceAsStream(resource);
sqlSessionFactory=new SqlSessionFactoryBuilder().build(is);
} catch (Exception e) {
e.printStackTrace();
}
}
public static SqlSession getSqlSession(){
return sqlSessionFactory.openSession();
}
}
在其中准备连接数据库所需资源(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>
<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/wang?useUnicode=true&amp;characterEncoding=UTF-8" />
<property name="username" value="root" />
<property name="password" value="123456" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/wang/dao/UserMapp.xml"></mapper>
</mappers>
</configuration>

注:在mybatis-config.xml文件中 需要与第二步中的Mapp建立联系,格式如下:
    <mappers>
<mapper resource="com/wang/dao/UserMapp.xml"></mapper>
</mappers>


2.编写Dao中文件:(Dao接口,Mapp.xml)
Dao接口文件:可以在已添加接口
package com.wang.dao;

import com.wang.Pojo.User;
import java.util.List;
public interface UserDao {
List<User> getUser();//查
int  insertUser(User user);//增
int deleteUser(String id);//删
int updatetUser(User user);//改

}
Mapp.xml文件:
<?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.wang.dao.UserDao">
<select id="getUser" resultType="com.wang.Pojo.User">
SELECT * FROM user
</select>
<insert id="insertUser" parameterType="com.wang.Pojo.User" >
insert into user(id,name,email) value (#{id},#{name} ,#{email})
</insert>
<update id="updatetUser" parameterType="com.wang.Pojo.User" >
update user set name=#{name},email=#{email} where id=#{id}
</update>
<delete id="deleteUser" parameterType="String">
delete from user where id=#{id}
</delete>

</mapper>

注:其中nameSpace是Dao接口的文件
id为Dao接口中的方法
resultType为返回结果的类型


3.编写主程序:

//第一步,用工具类获取sqlSession。
SqlSession sqlSession = MybatisUtils.getSqlSession();
//第二步,获取Dao对象
UserDao userDao = sqlSession.getMapper(UserDao.class);
//第三步,通过Dao对象调用其中的方法,返回集合
// int num = userDao.insertUser(new User("09", "haha", "999"));
//        int num = userDao.updatetUser(new User("09", "lalala", "888"));
// int num = userDao.deleteUser("09");
// List<User> list = userDao.getUser();
// for(User u:list){
// System.out.println(u.toString());
// }
sqlSession.commit();//除查询之外,其他操作必须要有事务提交,否则不会更新表


sqlSession.close();//关闭资源
 

声明:(Mapp.xml导出资源问题):需要在pom.xml文件添加以下代码:
<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>

技术分享图片







Mybatis建立连接

原文:https://www.cnblogs.com/wanglala/p/13399055.html

(0)
(0)
   
举报
评论 一句话评论(0
关于我们 - 联系我们 - 留言反馈 - 联系我们:wmxa8@hotmail.com
© 2014 bubuko.com 版权所有
打开技术之扣,分享程序人生!