MyBatis-01第一个MyBatis程序-优快云博客

本文详细介绍如何从零开始使用MyBatis框架，包括环境搭建、核心配置文件编写、工具类创建、实体类定义、DAO接口及其实现，以及最终的单元测试。通过具体实例，展示MyBatis在Java项目中的集成和应用。

思路：搭建环境–》导入MyBatis–》编写代码–》测试

2.1：搭建环境

搭建数据库

CREATE DATABASE `mybatis`;
USE `mybatis`;
CREATE TABLE `user`(
 `id` INT(20) NOT NULL  PRIMARY KEY,
 `name` VARCHAR(30) DEFAULT NULL,
 `pwd` VARCHAR(30) DEFAULT NULL

) ENGINE=INNODB  DEFAULT CHARSET=utf8;

INSERT INTO `mybatis`.`user` 	(`id`, 	`name`, 	`pwd`	)
	VALUES
	('1', '徐源', '123456'),
	('2', '张三', '798456'),
	('3', 	'李四', '456123')

新建项目
创建一个普通的maven项目
删除src
导入maven依赖

<!--父工程-->
    <groupId>org.example</groupId>
    <artifactId>Mybatis-Study</artifactId>
    <version>1.0-SNAPSHOT</version>
<!--导入项目-->
    <dependencies>
        <!--mysql驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
           <version>5.1.47</version>
        </dependency>
        <!--junit-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
        <!--myBatis驱动-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.5</version>
        </dependency>

     
       
    </dependencies>

2.2创建一个模块

2.2.1 编写mybatis的核心配置文件

<?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><!--环境-->
    <environments default="development"><!--默认那个环境-->
        <environment id="development"><!--开发-->
            <transactionManager type="JDBC"/><!--事务管理-->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf8"/>
                <property name="username" value="root"/>
                <property name="password" value="123"/>
            </dataSource>
        </environment>
    </environments>

2.2.2编写mybatis工具类

package com.xuyuan.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;

//sqlsessionFactory--》sqlsession
public class Utils {
    private  static SqlSessionFactory sqlSessionFactory;
    static{
//获取SqlSessionFactory
        try {
            String resources="mybatis-config.xml";
            InputStream inputStream= Resources.getResourceAsStream(resources);
            SqlSessionFactory sqlSessionFactory= new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    // //获取SqlSession连接
    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();

    }

}

2.3编写代码
实体类

package com.xuyuan.Pojo;

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

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", pwd='" + pwd + '\'' +
                '}';
    }

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

    public User() {

    }

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }
}

Dao接口

package com.xuyuan.Dao;


import com.xuyuan.Pojo.User;

import java.util.List;

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

}

接口实现类

<?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.xuyuan.Dao">
    <select id="getUserList" resultType="com.xuyuan.Pojo.User">
        select * from mybatis.user
      </select>
</mapper>

测试
注意点
org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: java.io.IOException: Could not find resource com/xuyuan/Dao/UserMapper.xml

package com.xuyaun.Dao;

import com.xuyuan.Dao.UserDao;
import com.xuyuan.Pojo.User;
import com.xuyuan.Utils.Utils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class UserDaoTest {
    @Test
    public void getUserList() {
        SqlSession session = Utils.getSqlSession();
        //方法一:
        //List<User> users = session.selectList("com.kuang.mapper.UserMapper.selectUser");
        //方法二:
        UserDao mapper = session.getMapper(UserDao.class);
        List<User> users = mapper.getUserList();

        for (User user: users){
            System.out.println(user);
        }
        session.close();
    }
}

<build>
    <resources>
        <resource>
            <directory>src/main/java</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.xml</include>
            </includes>
            <filtering>false</filtering>
        </resource>
        <resource>
            <directory>src/main/resources</directory>
            <includes>
                <include>**/*.properties</include>
                <include>**/*.xml</include>
            </includes>
            <filtering>false</filtering>
        </resource>
    </resources>
</build>