[Java知识库] 创建第一个Mybatis项目（详细图解）

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[Java知识库]创建第一个Mybatis项目（详细图解）

一、创建一个Maven项目删除其中的src文件夹

二、Maven中在创建一个Maven项目该项目就为mybatis项目

三、配置mybatis所需要的架包

<dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.32</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.2.8</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>

        </dependency>


    </dependencies>

?四、创建实体类对象

package com.lisi.pojo;

public class User {
    private int id;
    private String name;
    private String pwd;

    public User() {

    }

    public User(int id, String name, String pwd) {
        this.id = id;
        this.name = name;
        this.pwd = pwd;
    }

    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 + '\'' +
                '}';
    }
}

必须与数据库中的保持一直

五、引入数据库资源

<?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/mybatis?userSSL=true&amp;useUncode=true&amp;characterEncoding=UTF-8" />
                <property name="username" value="root" />
                <property name="password" value="123456" />
            </dataSource>
        </environment>
    </environments>

<mappers>
    <mapper resource="com/lisi/dao/UserMapper.xml"></mapper>
</mappers>
</configuration>

五、编写工具类

package com.lisi.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.IOException;
import java.io.InputStream;

public class MybatisUtils {

    private static SqlSessionFactory sqlSessionFactory;
    static{
          try {
            String resources = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resources);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    //openSession包含面向数据库执行SQL命令的所有方法；
    public static SqlSession getSqlSession(){

        return sqlSessionFactory.openSession();
    }



}

六、定义接口

package com.lisi.dao;

import com.lisi.pojo.User;

import java.util.List;

public interface UserDao {
    List<User> getUserList();

}

七、定义接口对应的Mapper.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.lisi.dao.UserDao">
    <select id="getUserList" resultType="com.lisi.pojo.User" >
        select * from mybatis.user;
    </select>
</mapper>

八、测试运行

package com.lisi.dao;

import com.lisi.pojo.User;
import com.lisi.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();
        //执行SQL对象
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        List<User> userList = userDao.getUserList();


        for (User user : userList){
            System.out.println(user);
        }

        sqlSession.close();
    }
}

查看结果：