美文网首页程序员技术栈
mybatis笔记-基础示例

mybatis笔记-基础示例

作者: 欢喜流年 | 来源:发表于2019-06-25 23:37 被阅读2次

准备环境:安装jdk 、maven、mysql、Intellij IDEA

官方文档:http://www.mybatis.org/mybatis-3/zh/index.html

示例步骤

1.新建maven项目

1.png

2.在pom.xml中配置mybatis、mysql依赖


<dependencies>

<dependency>

<groupId>org.mybatis</groupId>

<artifactId>mybatis</artifactId>

<version>3.5.1</version>

</dependency>

<dependency>

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

<version>5.1.38</version>

</dependency>

</dependencies>

3.启动本地mysql服务,创建mysql数据库student,数据库中创建student表

2.png

4.创建Student类,类中属性与student表中字段一 一对应

public class Student{

int id;

String name;

String sex;

public Student(){

}

public Student(int id,String name,String sex){

this.id=id;

this.name=name;

this.sex=sex;

}

public int getId(){

returnid;

}

public void setId(intid){

this.id=id;

}

public String getName(){

returnname;

}

public void setName(String name){

this.name=name;

}

public String getSex(){

returnsex;

}

public void setSex(String sex){

this.sex=sex;

}

@Override

public String toString(){

return"Student{"+

"id="+id+

",name='"+name+'\''+

",sex='"+sex+'\''+

'}';

}

}

5.创建studentMapper.xml,在此文件中管理sql语句

<?xmlversion="1.0"encoding="UTF-8"?>

<!DOCTYPEmapper

PUBLIC"-//mybatis.org//DTDMapper3.0//EN"

"[http://mybatis.org/dtd/mybatis-3-mapper.dtd](http://mybatis.org/dtd/mybatis-3-mapper.dtd)">

<mapper namespace="orm.mapper.studentMapper">

<!--resultType:返回值类型 parameterType:参数类型-->

<selectid="selectById"

resultType="orm.entity.Student" parameterType="int">

select*from student where id=#{id}

</select>

</mapper>

6.创建config.xml配置文件,配置数据库连接信息、mapper信息

<?xmlversion="1.0"encoding="UTF-8"?>

<!DOCTYPEconfiguration

PUBLIC"-//mybatis.org//DTDConfig3.0//EN"

"[http://mybatis.org/dtd/mybatis-3-config.dtd](http://mybatis.org/dtd/mybatis-3-config.dtd)">

<configuration>

<environments default="development">

<environment id="development">

<transactionManager type="JDBC"/>

<!--此处配置数据库连接信息

type="POOLED":为用链接池方式访问数据库-->

<dataSource type="POOLED">

<property name="driver" value="com.mysql.jdbc.Driver"/>

<property name="url" value="jdbc:mysql://localhost:3306/student"/>

<property name="username" value="root"/>

<property name="password" value="xiaofu"/>

</dataSource>

</environment>

</environments>

<mappers>

<mapper resource="orm/mapper/studentMapper.xml"/>

</mappers>

</configuration>

7.测试一下

public class FirstBasicDemoTest{

public static void main(String[] args){

//获取sqlsession对象

String resource="firstBasicDemoConfigure.xml";

Reader reader=null;

try{

reader=Resources.getResourceAsReader(resource);

}catch(IOExceptione){

e.printStackTrace();

}

SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(reader);

SqlSessionsession=sqlSessionFactory.openSession();

//进行查询操作

Stringstatment="orm.mapper.studentMapper.selectById";

Studentstudent=session.selectOne(statment,1);

System.out.println(student);

}

}

运行结果:

image

运行程序时可能会报错:

mybatis读取配置文件报错:Could not find resource firstBasicDemoConfigure.xml
原因:在classes目录下没有找到配置文件,所以配置文件没有在编译范围
解决:在pom.xml中添加下方配置

<build>

<resources>

<resource>

<directory>src/main/java</directory>

<includes>

<include>**/*.xml</include>

</includes>

<filtering>true</filtering>

</resource>

</resources>

</build>

相关文章

网友评论

    本文标题:mybatis笔记-基础示例

    本文链接:https://www.haomeiwen.com/subject/bvbfcctx.html