前言

接着上文MP的知识点写Mybatis-Plus知识点[MyBatis+MyBatis-Plus的基础运用]_心态还需努力呀的博客-CSDN博客

这次是标题所示的MP+SpringBoot整合运用

一、创建Maven项目导入相关的依赖

<?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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>mp-springboot</artifactId>
    <version>1.0-SNAPSHOT</version>
    <!--设置父工程: 里面进行版本的锁定-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.2.RELEASE</version>
    </parent>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>



    <!--添加依赖-->
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.1</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
        </dependency>
    </dependencies>

    <!--编译jdk版本为1.8-->
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

二、在resources添加日志和连接数据库

1.日志文件(log4j.properties)

#??????
log4j.rootLogger=DEBUG,Console
#???????
log4j.appender.Console=org.apache.log4j.ConsoleAppender
log4j.appender.Console.layout=org.apache.log4j.PatternLayout
log4j.appender.Console.layout.ConversionPattern=%d [%t] %-5p [%c] - %m%n
#??????
log4j.logger.java.sql.ResultSet=INFO
log4j.logger.org.apache=INFO
log4j.logger.java.sql.Connection=DEBUG
log4j.logger.java.sql.Statement=DEBUG
log4j.logger.java.sql.PreparedStatement=DEBUG

2.连接数据库（application.properties）

spring.application.name=mp-springboot



spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/study?serverTimezone=UTC&characterEncoding=utf8&useUnicode=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=123

三、编写pojo （注解编写get/set/tostring）

package cn.imust.mp.pojo;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("user")
public class User {
    
    private Integer userId;

    
    private String userName;

   
    private String userPassword;

    private String userEmail;
    private String userRole;
    private String userStatus;

    


}

四、UserMapper编写继承BaseMapper

package cn.imust.mp.mapper;

import cn.imust.mp.pojo.User;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;

public interface UserMapper extends BaseMapper<User> {
}

五、SpringBoot运行主函数

package cn.imust.mp;

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

@MapperScan("cn.imust.mp.mapper")
@SpringBootApplication
public class MyApplication {
    public static void main(String[] args) {
        SpringApplication.run(MyApplication.class,args);
    }
}

六、编写测试类（查询所有）

@Autowired
    private UserMapper userMapper;
//    测试查询所有selectList
    @Test
    public void testSelectList(){
        List<User> users = userMapper.selectList(null);
        for (User user : users) {
            System.out.println(user);
        }
    }

七、测试结果

总结

如果会配置springBoot的话只需要在mapper中继承mybatis-plus然后去调用里面的方法即可。有很多的现成的增删改查函数直接调用某个方法即可。用法很简单，但下节会说一下很多的小细节，如数据库表与设置变量非驼峰该怎么对应？设置的变量值数据库表中没有，但调用增加方法时有该值怎么办？id自增通过id查询怎么实现？其实就是下篇文章主要是讲解@TableField的用法。

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