Mybatis一站式新手入门（IDEA）

#Mybatis官网入门地址：https://mybatis.org/mybatis-3/zh/getting-started.html

#创建空项目，创建Maven模块

#配置pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>mybatisDemo</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>test</artifactId>
    <packaging>jar</packaging>
    <name>test</name>
    <url>http://maven.apache.org</url>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <!-- mybatis 依赖 -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.1</version>
        </dependency>
        <!--mysql依赖-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.9</version>
        </dependency>
    </dependencies>
    <build>
        <resources>
            <resource>
                <!--所在的目录-->
                <directory>src/main/java</directory>
                <includes>
                    <!--包括目录下的.properties .xml文件都会扫描到-->
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>
</project>

#创建resources文件夹

#创建一个User类(根据数据库表)
public  class User {
    private int p_id;
    private String p_name;
    private String address;
    private String birth;
private String gender;
get+set方法(自行脑补--)
}

#创建User接口

#创建sql映射文件UserDao.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!--约束文件   mybatis-3-mapper.dtd约束文件的名称，扩展名btd（用来限制和检测当前文件中出现的标签，属性必须符合mybatis的要求）-->
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--namespace名称空间,唯一，可自定义，要求使用dao接口的全限定名称-->
<!--mapper是当前文件的根标签 dao的全限定名称    resultType返回结果类型   id唯一标识-->
<mapper namespace="org.example.dao.UserDao">
    <select id="selectUsers" resultType="org.example.domain.User">
        SELECT * FROM TEST1;
    </select>
<!--
    <update id=""></update>
    <insert id=""></insert>
-->
</mapper>
<!--sql映射文件：写sql语句的 ，mybatis会执行这些sql-->

#尝试编译

#创建mybatis主配置文件mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- default必须和environment值一样-->
    <environments default="myuser">
<!--environment可以有多个 但id唯一-->
        <environment id="myuser">
<!--transactionManager，mybatis的事务类型 commit rollback-->
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://IP:3306/mysql?"/>
                <property name="username" value="root"/>
                <property name="password" value="password"/>
            </dataSource>
        </environment>
    </environments>
<!-- mapper sql映射文件的位置   target/classes类路径-->
    <mappers>
        <mapper resource="org/example/dao/UserDao.xml"/>
    </mappers>
</configuration>
<!--mybatis主配置文件:主要定义了数据库的配置信息，sql映射文件的位置-->

#创建一个测试类
public class Sqltest {
    public static void main(String[] args) throws IOException {
        //mybatis读取User数据
        //1.定义mybatis主配置文件名称，从类路径开始(target/clasess)
        String resource = "mybatis-config.xml";
        //读取mybatis-config.xml文件
        InputStream inputStream = Resources.getResourceAsStream(resource);
        //创建SqlSessionFactory对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //(关键)获取sqlSessionFactory对象，从SqlSessionFactory中获取sqlSession
        SqlSession sqlSession =sqlSessionFactory.openSession();
        //(关键)指定要执行的sql语句的标识。(sql映射文件的namesapce+id标识)
        String Sqlmapper ="org.example.dao.UserDao.selectUsers";
        //执行sql语句
        List<User> userList = sqlSession.selectList(Sqlmapper);
        //输出结果
        //userList.forEach(users -> System.out.println(users));
        for (User u:userList) {System.out.println(u);}
        //释放资源
        sqlSession.close();
    }
}

#重新编译一遍，执行