springboot整合mybatis-plus

准备工作

创建一个springboot 2.7.2版本的新项目

建议去官网生成一个springboot项目,官网地址：https://start.spring.io/

代码编写工作

pom依赖添加 web,mybatis-plus,mysql

<?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>2.7.2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>cn.lzh</groupId>
    <artifactId>kam</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>kam</name>
    <description>kam</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <fork>true</fork>
                    <addResources>true</addResources>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

创建一个mysql数据库表

CREATE DATABASE `kam` /*!40100 DEFAULT CHARACTER SET utf8mb4 */;

-- kam.t_user definition

CREATE TABLE `t_user` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT 'uid',
  `name` varchar(100) NOT NULL COMMENT 'username',
  `pwd` varchar(100) NOT NULL DEFAULT '1' COMMENT 'password',
  `c_time` datetime NOT NULL COMMENT 'createTime',
  `u_time` datetime NOT NULL COMMENT 'updateTime',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8mb4;

INSERT INTO kam.t_user (name,pwd,c_time,u_time) VALUES
         ('qwe','1','2022-08-13 12:07:18','2022-08-13 12:07:18');

配置springboot默认配置文件application.properties

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/kam?useSSL=false&serverTimezone=UTC&characterEncoding=utf-8
spring.datasource.username=root
spring.datasource.password=123456
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

实体类创建

package cn.lzh.kam.orm.entity;

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.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.time.LocalDateTime;

@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
@TableName("t_user")
public class User {

    @TableId(type = IdType.AUTO)
    private Long id;
    @TableField(value = "name")
    private String name;
    @TableField(value = "pwd")
    private String pwd;
    @TableField(value = "c_time")
    private LocalDateTime cTime;
    @TableField(value = "u_time")
    private LocalDateTime uTime;
}

Mapper接口层创建

package cn.lzh.kam.orm.mapper;

import cn.lzh.kam.orm.entity.User;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface UserMapper extends BaseMapper<User> {

}

项目启动器配置Mapper扫描

package cn.lzh.kam;

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

@SpringBootApplication
@MapperScan("cn.lzh.kam.orm.mapper")
public class KamApplication {

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

测试mybatis-plus效果

测试代码测试UserMapper执行效果

package cn.lzh.kam;

import cn.lzh.kam.orm.entity.User;
import cn.lzh.kam.orm.mapper.UserMapper;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;

import javax.annotation.Resource;

@SpringBootTest
class KamApplicationTests {

    @Resource
    private UserMapper userMapper;

    @Test
    void contextLoads() {
        User user = userMapper.selectById(1);
        System.err.println(user);
    }

}

执行效果