[Java知识库]阶段二：MyBatisPlus整合

目录

一、MyBatis+MyBatis-Plus：

第一步：将UserMapper继承BaseMapper

第二步：使用MyBatisPlus的MybatisSqlSessionFactoryBuilder进程构建：

第三步：在实体类上添加@TableName，指定数据库表名：

简单说明：

二、Spring+MyBatis+MyBatisPlus：

创建项目导入依赖：

编写数据库配置文件：

第一步：编写jdbc.properties：

第二步：编写applicationContext.xml：

第三步：编写实体类对象以及UserMappper接口：

第四步：编写测试用例：

三、SpringBoot+MyBatis+MyBatisPlus：

第一步：创建工程，导入依赖：

第二步：编写配置文件：

第三步：编写实体类：

第四步：编写启动类：

第五步：编写测试用例：

传送口：回顾MyBatis

一、MyBatis+MyBatis-Plus：

第一步：将UserMapper继承BaseMapper

继承BaseMapper之后，该接口将拥有BaseMapper中的所有方法：

package com.krian.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.krian.pojo.User;

import java.util.List;

public interface UserMapper extends BaseMapper<User> {
    public List<User> findAll();
}

第二步：使用MyBatisPlus的MybatisSqlSessionFactoryBuilder进程构建：

package com.krian;

import com.baomidou.mybatisplus.core.MybatisSqlSessionFactoryBuilder;
import com.krian.mapper.UserMapper;
import com.krian.pojo.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.junit.Test;

import java.io.InputStream;
import java.util.List;


public class TestMyBatisPlus {

    @Test
    public void testUserFindAll() throws Exception{

        //加载MyBatis核心配置文件：
        String resource = "mybatis-config.xml";
        //通过文件流的方式加载核心配置文件
        InputStream inputStream = Resources.getResourceAsStream(resource);

        //通过MybatisSqlSessionFactoryBuilder整合MyBatisPlus插件
        SqlSessionFactory sqlSessionFactory = new MybatisSqlSessionFactoryBuilder().build(inputStream);

        //通过sqlSessionFactory获取SqlSession会话：
        SqlSession sqlSession = sqlSessionFactory.openSession();

        //通过sqlSession加载Mapper文件，获取Mapper对象：
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        //通过BaseMapper中定义的方法：
        List<User> list = mapper.selectList(null); //调用了MyBatisPlus方法，参数查询条件

        for (User user:list){
            System.out.println(user);
        }
    }
}

第三步：在实体类上添加@TableName，指定数据库表名：

package com.krian.pojo;

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

@Data
@NoArgsConstructor
@AllArgsConstructor
@SuppressWarnings({"all"})
@TableName(value = "tb_user") //MyBatisPlus数据库表映射
public class User {

        private Long id;
        private String userName;
        private String password;
        private String name;
        private Integer age;
        private String email;
}

测试：

[main] [com.krian.mapper.UserMapper.selectList]-[DEBUG] ==>  Preparing: SELECT id,user_name,password,name,age,email FROM tb_user
[main] [com.krian.mapper.UserMapper.selectList]-[DEBUG] ==> Parameters: 
[main] [com.krian.mapper.UserMapper.selectList]-[DEBUG] <==      Total: 5
User(id=1, userName=zhangsan, password=123456, name=张三, age=18, email=test1@itcast.cn)
User(id=2, userName=lisi, password=123456, name=李四, age=20, email=test2@itcast.cn)
User(id=3, userName=wangwu, password=123456, name=王五, age=28, email=test3@itcast.cn)
User(id=4, userName=zhaoliu, password=123456, name=赵六, age=21, email=test4@itcast.cn)
User(id=5, userName=sunqi, password=123456, name=孙七, age=24, email=test5@itcast.cn)

简单说明：

由于使用了MybatisSqlSessionFactoryBuilder进行了构建，继承的BaseMapper中的方法就载入到了SqlSession中，所以就可以直接使用相关的方法

二、Spring+MyBatis+MyBatisPlus：

引入了Spring框架，数据源、构建等工作就交给了Spring进行管理！！！

创建项目导入依赖：

<?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">
    <parent>
        <artifactId>MyBatis-Plus</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>mybatisPlus-Spring</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <spring.version>5.1.6.RELEASE</spring.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!--MyBatis-Plus依赖-->
        <!-- https://mvnrepository.com/artifact/com.baomidou/mybatis-plus-generator -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-generator</artifactId>
            <version>3.4.0</version>
        </dependency>

        <!--mybatis依赖-->
        <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.7</version>
        </dependency>
        
        <!--MySQL连接依赖-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.25</version>
        </dependency>

        <!-- 连接池 -->
        <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.4</version>
        </dependency>
        
        <!--简化bean代码的工具包-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
            <version>1.18.20</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-log4j12 -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.32</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

编写数据库配置文件：

第一步：编写jdbc.properties：

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/mybatis_plus? useUnicode=true&characterEncoding=utf8&autoReconnect=true&allowMultiQueries=true&useSSL=false
jdbc.username=root
jdbc.password=131452

第二步：编写applicationContext.xml：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">

    <!--配置文件扫描器-->
    <context:property-placeholder location="classpath:*.properties"/>

    <!-- 定义数据源 -->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close">
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
        <property name="driverClassName" value="${jdbc.driver}"/>
        <property name="maxActive" value="10"/>
        <property name="minIdle" value="5"/>
    </bean>

    <!--这里使用MyBatisPlus提供的sqlSessionFactory，完成了Spring与MyBatisPlus的整合-->
    <bean id="sqlSessionFactory" class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
    </bean>

    <!--扫描mapper接口，使用的依然是Mybatis原生的扫描器-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.krian.mapper"/>
    </bean>

</beans>

第三步：编写实体类对象以及UserMappper接口：

package com.krian.pojo;

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

@Data
@NoArgsConstructor
@AllArgsConstructor
@SuppressWarnings({"all"})
@TableName(value = "tb_user") //MyBatisPlus数据库表映射
public class User {

    private Long id;
    private String userName;
    private String password;
    private String name;
    private Integer age;
    private String email;
}
package com.krian.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.krian.pojo.User;

public interface UserMapper extends BaseMapper<User> {
}

第四步：编写测试用例：

package com.krian.test;

import com.krian.mapper.UserMapper;
import com.krian.pojo.User;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import java.util.List;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:applicationContext.xml")
public class TestSpringMyBatisPlus {

    @Autowired
    UserMapper userMapper;

    @Test
    public void test(){
        List<User> list = userMapper.selectList(null);

        for (User user : list){
            System.out.println(user);
        }
    }
}

输出：

User(id=1, userName=zhangsan, password=123456, name=张三, age=18, email=test1@itcast.cn)
User(id=2, userName=lisi, password=123456, name=李四, age=20, email=test2@itcast.cn)
User(id=3, userName=wangwu, password=123456, name=王五, age=28, email=test3@itcast.cn)
User(id=4, userName=zhaoliu, password=123456, name=赵六, age=21, email=test4@itcast.cn)
User(id=5, userName=sunqi, password=123456, name=孙七, age=24, email=test5@itcast.cn)

三、SpringBoot+MyBatis+MyBatisPlus：

使用SpringBoot将进一步的简化MP的整合，需要注意的是，由于使用SpringBoot需要继承parent，所以需要重新创建工程，并不是创建子Module。

第一步：创建工程，导入依赖：

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.krian</groupId>
    <artifactId>MyBatisPlus-SpringBoot</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>MyBatisPlus-SpringBoot</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!--简化代码的工具包-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!--mybatis-plus的springboot支持-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.4.0</version>
        </dependency>
        <!--mysql驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.25</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

第二步：编写配置文件：

日志配置文件：log4j.properties

log4j.rootLogger=DEBUG,A1

log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=[%t] [%c]-[%p] %m%n

数据库配置文件：application.properties

# 项目名称：
spring.application.name = MyBatisPlus-SpringBoot

# 数据库连接配置信息：
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/mybatis_plus? useUnicode=true&characterEncoding=utf8&autoReconnect=true&allowMultiQueries=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=131452

第三步：编写实体类：

package com.krian.mybatisplusspringboot.pojo;

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

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("tb_user")
public class User {
    private Long id;
    private String userName;
    private String password;
    private String name;
    private Integer age;
    private String email;
}

第四步：编写启动类：

package com.krian.mybatisplusspringboot;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@MapperScan("com.krian.mybatisplusspringboot.mapper") //设置mapper接口的扫描包
@SpringBootApplication
public class MyBatisPlusSpringBootApplication {

    public static void main(String[] args) {
        SpringApplication.run(MyBatisPlusSpringBootApplication.class, args);
    }
}

第五步：编写测试用例：

package com.krian.mybatisplusspringboot;

import com.krian.mybatisplusspringboot.mapper.UserMapper;
import com.krian.mybatisplusspringboot.pojo.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

@SpringBootTest
@SuppressWarnings({"all"})
class MyBatisPlusSpringBootApplicationTests {

    @Autowired
    private UserMapper userMapper;

    @Test
    public void test(){
        List<User> list = userMapper.selectList(null);
        for (User user : list) {
            System.out.println(user);
        }
    }
}

测试：

User(id=1, userName=zhangsan, password=123456, name=张三, age=18, email=test1@itcast.cn)
User(id=2, userName=lisi, password=123456, name=李四, age=20, email=test2@itcast.cn)
User(id=3, userName=wangwu, password=123456, name=王五, age=28, email=test3@itcast.cn)
User(id=4, userName=zhaoliu, password=123456, name=赵六, age=21, email=test4@itcast.cn)
User(id=5, userName=sunqi, password=123456, name=孙七, age=24, email=test5@itcast.cn)