初学Mybatis，IDEA创建一个简单的项目，超详细，有手就行

1.创建项目

至此项目创建完成

2.修改pom.xml

原来的pom.xml文件是这样的

然后加了一句注释

接着在注释下面添加下面的一段代码

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

<dependencies>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.20</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.5</version>
    </dependency>

    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
</dependencies>

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

3.创建mybatis-config.xml

mybatis-config.xml是mybat的核心配置文件

1.选择main下面的resources文件夹

2.右键，new->File

3.输入文件名，创建完毕

4.创建db.properties

也是在resource文件夹下面，new->File，输入db.properties，创建完毕

5.配置db.properties

driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/mybatis?useSSL=true&useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
username=root
password=123456

6.配置mybatis-config.xml

在mybatis-config.xml粘贴下面的代码，这里我先把注释掉了，后面会说

<configuration>
    
    <properties resource="db.properties"/>
    
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            dataSource>
        environment>
    environments>
    

configuration>

我们用引入了刚刚写的db.properties文件,${driver}等这些就是取得db.properties文件里面设置的值

7.创建包

1.选中main下的java文件夹

2.右键，new->Package

3.输入包名com.zzh
然后在com.zzh包下，再建三个包，分别是dao，pojo，utils

包创建完成

8.创建utils包下的工具类MybatisUtils.java

右键utils包，new->Java Class，输入MybatisUtils

MybatisUtils.java的完整代码如下

package com.zzh.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;

/**
 * @author zzh
 * @create 2020
 */
public class MybatisUtils {
     
    private static SqlSessionFactory sqlSessionFactory;
    static {
     
        try {
     
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
     
            e.printStackTrace();
        }
    }

    public static SqlSession getSqlSession(){
     
        return sqlSessionFactory.openSession();
    }
}

工具类创建完成

9.创建pojo包下面的实体类User.java

1.右键pojo包，new->Java Class

2.输入User，确定

3.User.java的完整代码如下

package com.zzh.pojo;

/**
 * @author zzh
 * @create 2020
 */
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 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;
    }

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

10.在dao包下创建接口UserMapper

1.右键dao包，new->Java Class

2.输入UserMapper，并选择Interface，确定

3.UserMapper接口的完整代码如下

package com.zzh.dao;

import com.zzh.pojo.User;

import java.util.List;

/**
 * @author zzh
 * @create 2020
 */
public interface UserMapper {
     
    //查询全部用户
    List<User> getUserList();

    //根据ID查询用户
    User getUserById(int id);

    //insert插入一个用户
    int addUser(User user);

    //update修改用户
    int updateUser(User user);

    //delete删除用户
    int deleteUser(int id);
}

11.创建dao包下的UserMapper.xml

1.右键dao包，new->File

2.输入UserMapper.xml，确定

3.UserMapper.xml的完整代码如下

<mapper namespace="com.zzh.dao.UserMapper">
    <select id="getUserList" resultType="com.zzh.pojo.User">
        select * from user
    select>

    <select id="getUserById" parameterType="int" resultType="com.zzh.pojo.User">
        select * from user where id = #{id}
    select>

    <insert id="addUser" parameterType="com.zzh.pojo.User">
        insert into user (id, name, pwd) values (#{id} ,#{name} ,#{pwd})
    insert>

    <update id="updateUser" parameterType="com.zzh.pojo.User">
        update user set name=#{name},pwd=#{pwd} where id = #{id}
    update>

    <delete id="deleteUser" parameterType="int">
        delete from user where id=#{id}
    delete>
mapper>

4.到这里就可以回到mybatis-config.xml那里，把注释取消掉了

12.创建测试类

1.选中test文件夹下的绿色java文件夹

2.右键，new->Package

3.输入com.zzh.dao，确定

4.选中刚创建的dao包，new->Java Class，输入UserMapperTest，确定

5.UserMapperTest.java的完整代码如下

package com.zzh.dao;

import com.zzh.pojo.User;
import com.zzh.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

/**
 * @author zzh
 * @create 2020
 */
public class UserMapperTest {
     
    @Test
    public void test(){
     
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList = mapper.getUserList();
        for (User user : userList) {
     
            System.out.println(user);
        }
        sqlSession.close();
    }

    @Test
    public void getUserById(){
     
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = mapper.getUserById(1);
        System.out.println(user);

        sqlSession.close();
    }

    @Test
    public void addUser(){
     
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.addUser(new User(4,"王五","123321"));
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void updateUser(){
     
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.updateUser(new User(4,"赵六","123321"));
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void deleteUser(){
     
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.deleteUser(4);
        sqlSession.commit();
        sqlSession.close();
    }

}

13.创建数据库和表

1.创建数据库mybatis

2.在里面创建一个user表，表的设置如下

3.在里面输入一些数据

全部工作就完成了

14.成功运行

点击每一个Test方法前的绿色小三角，就可以运行


其他运行也一样，至此第一个Mybatis项目算是成功了