IDEA创建Maven项目（Mybatis测试2020.6.23）

1.创建

直接下一步

2.输入项目名字

3.创建目录

4.配置pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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">
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.example</groupId>
    <artifactId>mybatis</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.20</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.3</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>
    </build>
</project>

5.再resource目录下创建mybatis-config.xml

<?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">
<!--            使用JDBC事务管理-->
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/travel?serverTimezone=UTC"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>

<!--    映射文件的位置-->
    <mappers>
        <mapper resource="com/mybatis/mapper/UserMapper.xml"/>
    </mappers>
</configuration>片

这里注意两点
1.数据源的url参数要有serverTimezone=UTC,否则会报时区错误
2.映射文件路径正确

6.创建相关实体类User和接口UserDao

代码省略

7.创建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">
<mapper namespace="com.mybatis.dao.UserMapper">
<!--    插入一位用户数据-->
    <insert id="addUser" parameterType="com.mybatis.po.MyUser">
        insert into tab_user (username,password) values(#{username},#{password})
    </insert>

</mapper>

这里注意 mapper namespace的写法

8.测试调用

public static void main(String[] args) {
        try {
            //读取配置文件
            InputStream in = Resources.getResourceAsStream("mybatis-config.xml");
            //根据配置文件构造Factory
            SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(in);
            //获取Sqlsession
            SqlSession sqlSession = sessionFactory.openSession();
            //开始使用
//            查询
            MyUser user = new MyUser();
            user.setPassword("123456");
            user.setUsername("aaaaaa");
            sqlSession.insert("com.mybatis.dao.UserMapper.addUser",user);

            sqlSession.commit();
            sqlSession.close();
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

1.测试步骤：读取配置文件mybatis-config.xml文件->创建工厂SqlSessionFactory->工厂生产SqlSession对象，然后调用相关的方法。
2.SqlSession对象调用insert方法时，第一个参数是映射文件命名空间+sql标签语句的id,第二个是传入的参数
3.使用完要提交事务
4.记得关闭SqlSession对象以及InputStream流
5.如果出现JDK版本问题则可在项目配置中修改JDK的版本