maven-Mybatis学习

Mybatis是一个半成品，优点：①操作难度比jdbc少。②不需要导入jar包，只需要导入坐标即可；缺点：①步骤比较繁琐

Mybatis中文网，这个网址里面有mybatis的配置步骤

1、创建数据库,数据自己插入几条就可以

create datebase mybatis;
use mybatis;
create table tb_user(
   id int auto_increment primary key,
   username varchar(20),
   password varchar(20),
   gender char(2),
   addr varchar(20)    
);

文件结构

 

 

2、创建moudle，maven-demo，在pom.xml中导入依赖

<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>5.1.48</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.20</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.3</version>
        </dependency>

        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
            <version>1.2.3</version>
        </dependency>
    </dependencies>

3、将logback.xml文件复制到resource下

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <!--定义日志文件的存储地址 勿在 LogBack 的配置中使用相对路径-->
    <property name="LOG_HOME" value="E:/log" />
    <!-- 控制台输出 -->
    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
        <!-- 日志输出编码 -->
        <Encoding>UTF-8</Encoding>
        <layout class="ch.qos.logback.classic.PatternLayout">
            <!--格式化输出：%d表示日期，%thread表示线程名，%-5level：级别从左显示5个字符宽度%msg：日志消息，%n是换行符-->
            <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n
            </pattern>
        </layout>
    </appender>
    <!-- 按照每天生成日志文件 -->
    <appender name="FILE"  class="ch.qos.logback.core.rolling.RollingFileAppender">
        <Encoding>UTF-8</Encoding>
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!--日志文件输出的文件名-->
            <FileNamePattern>${LOG_HOME}/myApp.log.%d{yyyy-MM-dd}.log</FileNamePattern>
            <MaxHistory>30</MaxHistory>
        </rollingPolicy>
        <layout class="ch.qos.logback.classic.PatternLayout">
            <!--格式化输出：%d表示日期，%thread表示线程名，%-5level：级别从左显示5个字符宽度%msg：日志消息，%n是换行符-->
            <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n
            </pattern>
        </layout>
        <!--日志文件最大的大小-->
        <triggeringPolicy class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
            <MaxFileSize>1MB</MaxFileSize>
        </triggeringPolicy>
    </appender>
 
    <!-- 日志输出级别 -->
    <root level="ALL">
        <appender-ref ref="CONSOLE" />
        <appender-ref ref="FILE" />
    </root>
 
</configuration>

4、在resource下创建mybatis-config文件，这个在mybatis网址中也有

<?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：配置数据库连接环境信息。可以配置多个environment，通过default属性切换不同环境-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
<!--                链接信息-->
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=false"/>
                <property name="username" value="root"/>
                <property name="password" value="jia237106-"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
<!--        加载sql映射文件-->
        <mapper resource="com/it/mapper/userMapper.xml"/>
    </mappers>
</configuration>

5、创建UserMapp.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">

<!--名称空间-->
<mapper namespace="test">
    <select id="selectAll" resultType="com.it.pojo.User">
        select * from tb_user;
    </select>
</mapper>

 

6、创建User类

7、测试

package com.it;

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;
import java.util.List;

//mybatis入门代码
public class MyBatisDemo {
    public static void main(String[] args) {
//        1、加载mybatis核心配置文件，获取sqlSessionFactory
        String resource = "mybatis-config.xml";
        InputStream inputStream = null;
        try {
            inputStream = Resources.getResourceAsStream(resource);
        } catch (IOException e) {
            e.printStackTrace();
        }
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

//        2、获取SqlSession对象，用来执行sql
        SqlSession sqlSession = sqlSessionFactory.openSession();

//        3、执行sql
        List<Object> users = sqlSession.selectList("test.selectAll");
        System.out.println(users);
//        4、释放资源
        sqlSession.close();
    }
}

写到这里就完成了。