MyBatisPlus基础学习

1.首先创建一个Maven工程

1.1：添加依赖

<dependencies>
        <!-- mybatis-plus插件依赖 -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus</artifactId>
            <version>3.1.1</version>
        </dependency>
        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        <!-- 连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.11</version>
        </dependency>
        <!--简化bean代码的工具包,简化实体类的工具-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
            <version>1.18.4</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <!--关于日志的-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.6.4</version>
        </dependency>
    </dependencies>

有两个插件可以添加：

<build>
        <plugins>
            <plugin>
                <!--规定jdk版本-->
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.4.2</version>
                <!--跳过测试-->
                <configuration>
                    <skipTests>true</skipTests>
                </configuration>
            </plugin>
        </plugins>
    </build>

2.添加一个xml文件

注意我这里的数据库是5版本的，8版本的跟我不一样

<?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">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/day16?serverTimezone=Hongkong&amp;useUnicode=true&amp;characterEncoding=utf8&amp;autoReconnect=true&amp;allowMultiQueries=true&amp;useSSL=false"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>

    <!--包扫描-->
    <mappers>
        <package name="com.dao"/>
    </mappers>
</configuration>

3.创建一个实体类：

package com.pojo;

import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

//lombok注解
@Data
@NoArgsConstructor
@AllArgsConstructor

//mybatisPlus注解，指明与该实体类相关联的表名
@TableName("dog")
public class dog {
    private int id;
    private String username;
    private String address;
}

4.创建一个实现接口：

package com.dao;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.pojo.dog;

//将dogMapper继承BaseMapper，将拥有BaseMapper中所有方法
public interface dogMapper extends BaseMapper<dog> {


}

5.测试：

import javax.annotation.Resource;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class myBatisPlusTest01 {
    @Test
    public void test01() throws IOException {
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);

        //这里使用的是MP中的MybatisSqlSessionFactoryBuilder
        SqlSessionFactory sqlSessionFactory = new MybatisSqlSessionFactoryBuilder().build(inputStream);
        SqlSession sqlSession = sqlSessionFactory.openSession();
        dogMapper dogMapper = sqlSession.getMapper(dogMapper.class);

        // 可以调用BaseMapper中定义的方法, 不带条件查询所有
        // selectList()方法是MybatisPlus提供的
        List<dog> list = dogMapper.selectList(null);
        for (dog user : list) {
            System.out.println(user);
        }
    }

}