如何创建mybatis工程？

目录

一、创建项目

二、引入相关依赖和插件

三、创建一个包pojo,在该包下创建一个实体类User

四、创建一个包mapper,在该包下创建一个接口UserMapper

五、在resources文件夹下创建mybatis-config.xml文件

六、测试类

一、创建项目

    使用idea创建一个maven 项目，比较简单这里不演示了。

二、引入相关依赖和插件

 <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>
      <build>
        <!-- 如果不添加此节点src/main/java目录下的所有配置文件都会被漏掉。 -->
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <!--让idea识别resources目录-->
            <resource>
                <directory>src/main/resources</directory>
            </resource>
        </resources>
    </build>

三、创建一个包pojo,在该包下创建一个实体类User

/*
 * Copyright (c) 2020, 2023, webrx.cn All rights reserved.
 *
 */
package com.by.pojo;


import java.io.Serializable;
import java.util.Date;

public class User implements Serializable {
    private Integer id;
    private String username;
    private Date birthday;
    private String sex;
    private String address;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", birthday=" + birthday +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

四、创建一个包mapper,在该包下创建一个接口UserMapper

package com.by.mapper;


import com.by.pojo.User;

import java.util.List;

public interface UserMapper {
    public List<User> findAll();
}

在该包下创建一个UserMapper的映射文件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 一般是接口的全类名-->
<mapper namespace="com.by.mapper.UserMapper">
    <!--
      id:和接口方法名保持一致
      resultType:和接口返回类型保持一致
     -->
    <select id="findAll" resultType="com.by.pojo.User">
        select * from user
    </select>
</mapper>

五、在resources文件夹下创建mybatis-config.xml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>
    <!-- 和spring整合后 environments配置将废除-->
    <environments default="dev">
        <!-- dev环境 -->
        <environment id="dev">
            <!-- 配置事务的类型 -->
            <transactionManager type="JDBC"></transactionManager>
            <!-- 配置连接数据库的信息：用的是数据源(连接池) -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3305/mybatis?characterEncoding=UTF-8"/>
                <property name="username" value="root"/>
                <property name="password" value=""/>
            </dataSource>
        </environment>
    </environments>
    <!-- 告知 mybatis 映射配置的位置 -->
    <mappers>
        <mapper resource="com/by/mapper/UserMapper.xml"/>
    </mappers>
</configuration>

六、测试类

/*
 * Copyright (c) 2020, 2023, webrx.cn All rights reserved.
 *
 */

import com.by.mapper.UserMapper;
import com.by.pojo.User;
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 org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

/**
 * <p>Project: Mybatis_02 - MyBatisTest</p>
 * <p>Powered by webrx On 2023-12-28 15:27:58</p>
 * <p>描述：<p>
 *
 * @author 简单遗忘 [814736551@qq.com]
 * @version 1.0
 * @since 17
 */
public class MyBatisTest {

    private InputStream inputStream;
    private SqlSession sqlSession;

    @Before
    public void createSqlSession() throws IOException {
        // 加载配置文件
        String resource = "mybatis-config.xml";
        inputStream = Resources.getResourceAsStream(resource);

        // 创建SqlSessionFactory
        SqlSessionFactory sqlSessionFactory =
                new SqlSessionFactoryBuilder().build(inputStream);
        //获得数据库会话实例
        sqlSession = sqlSessionFactory.openSession();
    }

    @Test
    public void testFindAll(){
        UserMapper userDao = sqlSession.getMapper(UserMapper.class);
        List<User> userList = userDao.findAll();
        for(User user : userList) {
            System.out.println(user);
        }
    }

    @After
    public void closeSqlSession() throws IOException {
        sqlSession.close();
        inputStream.close();
    }
}

 

 七、结果