Springboot系列之：创建Springboot项目，Springboot整合MyBatis-plus

[一、快速创建Spring boot项目](#一、快速创建Spring boot项目)
二、项目完整目录
三、pom.xml
四、application.yaml
五、实体类
六、mapper
七、IService接口
八、Service实现类
九、配置类
十、枚举
十一、增删改查测试类
十二、服务测试类
十三、分页测试类
十四、枚举测试类
十五、乐观锁测试类

一、快速创建Spring boot项目

二、项目完整目录

三、pom.xml

xml 复制代码

<?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>2.7.1</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>

	<groupId>com.lovejava.boot</groupId>
	<artifactId>learnjava</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>learnjava</name>

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


	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>



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


		<dependency>
			<groupId>com.baomidou</groupId>
			<artifactId>mybatis-plus-boot-starter</artifactId>
			<version>3.4.2</version>
		</dependency>

		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
		</dependency>


		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
			<optional>true</optional>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-configuration-processor</artifactId>
			<optional>true</optional>
		</dependency>

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

		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>8.0.13</version>
		</dependency>




	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.8.1</version>
				<configuration>
					<source>8</source>
					<target>8</target>
				</configuration>
			</plugin>
		</plugins>
	</build>

</project>

四、application.yaml

yaml 复制代码

spring:
  application:
    name: learnjava

  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://10.129.88.141:3306/data_entry_test?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: datasight
    password: datasight123456!A


mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
#    log-impl: org.apache.ibatis.logging.log4j.Log4jImpl
#  global-config:
#    db-config:
#      table-prefix: t_
#      id-type: AUTO

  type-enums-package: com.lovejava.boot.enums

五、实体类

java 复制代码

import com.baomidou.mybatisplus.annotation.*;
import com.lovejava.boot.enums.SexEnum;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@TableName("user")
public class User {

    @TableId(value = "id",type=IdType.AUTO)
    private Long id;

//    @TableField("sname")
    private String name;

    private Integer age;

    private SexEnum sex;

    private String email;

    @TableField("isDeleted")
    @TableLogic
    private Integer isDeleted;

    @Version
    private Integer version;

}

六、mapper

java 复制代码

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.lovejava.boot.pojo.User;
import org.springframework.stereotype.Repository;

@Repository
public interface UserMapper extends BaseMapper<User> {
}

七、IService接口

IService 是 MyBatis-Plus 提供的一个通用 Service 层接口，它封装了常见的 CRUD 操作，包括插入、删除、查询和分页等。通过继承 IService 接口，可以快速实现对数据库的基本操作，同时保持代码的简洁性和可维护性。

IService 接口中的方法命名遵循了一定的规范，如 get 用于查询单行，remove 用于删除，list 用于查询集合，page 用于分页查询，这样可以避免与 Mapper 层的方法混淆。

java 复制代码

import com.baomidou.mybatisplus.extension.service.IService;
import com.lovejava.boot.pojo.User;

public interface UserService extends IService<User> {
}

八、Service实现类

java 复制代码

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.lovejava.boot.mapper.UserMapper;
import com.lovejava.boot.pojo.User;
import com.lovejava.boot.service.UserService;
import org.springframework.stereotype.Service;


@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {
}

九、配置类

java 复制代码

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.OptimisticLockerInnerInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@MapperScan("com.lovejava.boot.mapper")
public class MybatisPlusConfig {

    /**
     * 添加分页插件
     */
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        //添加乐观锁插件
        interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        // 如果配置多个插件, 切记分页最后添加
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        // 如果有多数据源可以不配具体类型, 否则都建议配上具体的 DbType
        return interceptor;
    }
}

十、枚举

java 复制代码

import com.baomidou.mybatisplus.annotation.EnumValue;
import lombok.AllArgsConstructor;
import lombok.Getter;

@Getter
@AllArgsConstructor
public enum SexEnum {

    MALE(1,"男"),

    FEMALE(2,"女");

    @EnumValue //将注解所标识的属性的值存储到数据库中
    private Integer sex;
    private String sexName;

}

十一、增删改查测试类

java 复制代码

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
import com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper;
import com.lovejava.boot.mapper.UserMapper;
import com.lovejava.boot.pojo.User;
import net.minidev.json.JSONUtil;
import org.junit.jupiter.api.Test;
import org.junit.platform.commons.util.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@SpringBootTest
public class MyBatisPlusTest {


    @Autowired
    private UserMapper userMapper;

    @Test
    public void testSelectList(){
        List<User> users = userMapper.selectList(null);
        System.out.println(users);
        users.forEach(System.out::println);
    }


    @Test
    public void testInsert(){
        User user = new User();
        user.setName("刘备");
        user.setAge(23);
        user.setEmail("fy@qq.com");
        int result = userMapper.insert(user);
        System.out.println("result:"+result);
        System.out.println("id:"+user.getId());
    }

    @Test
    public void testDelete(){
        int result = userMapper.deleteById(1860576442045870081L);
        System.out.println(result);

    }

    //DELETE FROM user WHERE name = ? AND age = ?
    @Test
    public void testDeleteByMap(){
        Map<String,Object> map = new HashMap<>();
        map.put("name","刘备");
        map.put("age",23);
        int result = userMapper.deleteByMap(map);
        System.out.println("result："+result);

    }

    //通过多个id实现批量删除
    @Test
    public void testDeleteBatchIds(){
        List<Integer> list = Arrays.asList(1, 2, 3);
        int result = userMapper.deleteBatchIds(list);
        System.out.println("result："+result);
    }


    @Test
    public void testUpdate(){
        User user = new User();
        user.setId(1860579637015023618l);
        user.setName("刘备");
        user.setEmail("lb@qq.com");
        int result = userMapper.updateById(user);
        System.out.println("result: " + result);
    }

    @Test
    public void testSelectById(){
        List<Long> list = Arrays.asList(1l, 2l, 3l);
        List<User> users = userMapper.selectBatchIds(list);
        users.forEach(System.out::println);

    }

    @Test
    public void testSelectByMap(){
        HashMap<String, Object> map = new HashMap<>();
        map.put("name","诸葛亮");
        map.put("age",20);
        List<User> users = userMapper.selectByMap(map);
        users.forEach(System.out::println);
    }



    @Test
    public void testConditionSelect(){
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.likeRight("name","刘备")
                .between("age",10,50)
                .isNotNull("email");
        List<User> users = userMapper.selectList(queryWrapper);
        users.forEach(System.out::println);
    }


    @Test
    public void testConditionOrder(){
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();

        queryWrapper.orderByDesc("age")
                .orderByAsc("id");

        List<User> users = userMapper.selectList(queryWrapper);
        users.forEach(System.out::println);

    }

    @Test
    public void deleteCondition(){
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();

        queryWrapper.isNull("email");
        int result = userMapper.delete(queryWrapper);
        System.out.println("result：" + result);
    }

    @Test
    public void updateCondition(){

        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.gt("age",20)
                .like("name","刘备")
                .or()
                .isNull("email");

        User user = new User();
        user.setName("诸葛亮");
        user.setEmail("zhugeliang@qq.com");
        int result = userMapper.update(user, queryWrapper);
        System.out.println("result： "+result);
    }


    //UPDATE user SET name=?, email=? WHERE isDeleted=0 AND (name LIKE ? AND (age > ? OR email IS NULL))
    @Test
    public void updateCondition2(){
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.like("name","诸葛亮")
                .and(i -> i.gt("age",20).or().isNull("email"));
        User user = new User();
        user.setName("张飞");
        user.setEmail("zhangfei@qq.com");

        int result = userMapper.update(user, queryWrapper);
        System.out.println("result："+result);

    }

    //UPDATE user SET name=?,email=? WHERE isDeleted=0 AND (name LIKE ? AND (age > ? OR email IS NULL))
    @Test
    public void updateCondition3(){
        UpdateWrapper<User> updateWrapper = new UpdateWrapper<>();
        updateWrapper.like("name","诸葛亮")
                .and(i -> i.gt("age",20).or().isNull("email"));
        updateWrapper.set("name","孙权").set("email","sunquan@qq.com");
        int result = userMapper.update(null,updateWrapper);
        System.out.println("result：" + result);

    }

    @Test
    public void selectCondition(){
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.select("name","age","email");
        List<Map<String, Object>> maps = userMapper.selectMaps(queryWrapper);
        maps.forEach(System.out::println);
    }


    //子查询
    //SELECT id,name,age,email,isDeleted FROM user WHERE isDeleted=0 AND (id IN (select id from user where id < 10))
    @Test
    public void selectCondition2(){

        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.inSql("id","select id from user where id < 10");
        List<User> users = userMapper.selectList(queryWrapper);
        users.forEach(System.out::println);
    }

    //模拟实际条件
    //SELECT id,name,age,email,isDeleted FROM user WHERE isDeleted=0 AND (age >= ? AND age <= ?)
    @Test
    public void getCondition(){
        String username = "";
        Integer startage = 20;
        Integer endage = 35;

        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        if(StringUtils.isNotBlank(username)){
            queryWrapper.like("name",username);
        }
        if(startage!=null){
            queryWrapper.ge("age",startage);
        }
        if(endage!=null){
            queryWrapper.le("age",endage);
        }

        List<User> users = userMapper.selectList(queryWrapper);
        users.forEach(System.out::println);
    }


    //SELECT id,name,age,email,isDeleted FROM user WHERE isDeleted=0 AND (age >= ? AND age <= ?)
    @Test
    public void getCondition2(){
        String username = "";
        Integer startage = 20;
        Integer endage = 35;

        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.like(StringUtils.isNotBlank(username),"name","孙权")
                .ge(startage!=null,"age",startage)
                .le(endage!=null,"age",endage);

        List<User> users = userMapper.selectList(queryWrapper);
        users.forEach(System.out::println);
    }

    @Test
    public void testSelectLambda(){
        String username = "";
        Integer startage = 20;
        Integer endage = 35;
        LambdaQueryWrapper<User> queryWrapper = new LambdaQueryWrapper<>();
        queryWrapper.like(StringUtils.isNotBlank(username),User::getName,username)
                .ge(startage!=null,User::getAge,startage)
                .le(endage!=null,User::getAge,endage);
        List<User> users = userMapper.selectList(queryWrapper);
        users.forEach(System.out::println);
    }


    //UPDATE user SET name=?,age=?,email=? WHERE isDeleted=0 AND (age >= ? AND age <= ?)
    @Test
    public void testUpdateLambda(){
        String username = "";
        Integer startage = 20;
        Integer endage = 35;
        LambdaUpdateWrapper<User> updateWrapper = new LambdaUpdateWrapper<>();
        updateWrapper.like(StringUtils.isNotBlank(username),User::getName,username)
                .ge(startage!=null,User::getAge,startage)
                .le(endage!=null,User::getAge,endage);

        updateWrapper.set(User::getName,"诸葛亮回来了").set(User::getAge,16).set(User::getEmail,"诸葛亮@qq" +
                ".com");
        int result = userMapper.update(null, updateWrapper);
        System.out.println("result: "+result);
    }


    @Test
    public void testOptimisticLocker2(){

        // 线程1
        //1.查询用户信息
        User user1 = userMapper.selectById(2);
        //2.修改用户信息
        user1.setName("马超1");
        user1.setAge(20);
        user1.setEmail("machao1@qq.com");

        //模拟另外一个线程执行了插队操作
        User user2 = userMapper.selectById(2);
        //2.修改用户信息
        user2.setName("马超2");
        user2.setAge(20);
        user2.setEmail("machao2@qq.com");
        userMapper.updateById(user2);

        //如果没有乐观锁就会覆盖插队线程的值
        //可以使用自旋锁来多次尝试提交
        userMapper.updateById(user1);
    }
}

十二、服务测试类

java 复制代码

import java.util.ArrayList;
import java.util.List;

@SpringBootTest
public class MyBatisPlusServiceTest {

    @Autowired
    private UserService userService;

    @Test
    public void testGetCount(){
        int count = userService.count();
        System.out.println("总记录数： "+count);
    }

    @Test
    public void testInsertBatch(){

        List<User> list = new ArrayList<>();
        for (int i = 1; i<= 10; i++){
            User user = new User();
            user.setName("fy"+i);
            user.setAge(20+i);
            user.setEmail("fy"+i+"qq.com");
            list.add(user);
        }
        boolean b = userService.saveBatch(list);
        System.out.println("操作结果："+b);

    }


}

十三、分页测试类

java 复制代码

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.lovejava.boot.mapper.UserMapper;
import com.lovejava.boot.pojo.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
public class MybatisPlusPluginsTest {

    @Autowired
    private UserMapper userMapper;


    @Test
    public void testSelectPage(){

        Page<User> page = new Page<>(1,1);
        userMapper.selectPage(page,null);
        page.getRecords().forEach(System.out::println);
        System.out.println(page.getTotal());
    }



    //SELECT COUNT(*) FROM user WHERE isDeleted = 0 AND (name LIKE ? AND age BETWEEN ? AND ? AND email IS NOT NULL)
    @Test
    public void testSelectConditionPage(){
        Page<User> page = new Page<>(1,1);

        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.likeRight("name","刘备")
                .between("age",10,50)
                .isNotNull("email");

        userMapper.selectPage(page,queryWrapper);

        System.out.println(page);

        System.out.println(page.getTotal());
        System.out.println(page.getRecords());
        System.out.println(page.getPages());
        System.out.println(page.hasNext());
        System.out.println(page.hasPrevious());

    }
}

十四、枚举测试类

java 复制代码

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

@SpringBootTest
public class MyBatisPlusEnumTest {

    @Autowired
    private UserMapper userMapper;

    @Test
    public void test(){
        User user = new User();
        user.setName("admin");
        user.setAge(23);
        user.setSex(SexEnum.MALE);
        user.setEmail("admin@qq.com");

        int result = userMapper.insert(user);
        System.out.println("result：" + result);

    }
}

十五、乐观锁测试类

实体类添加字段：

java 复制代码

    @Version
    private Integer version;

添加乐观锁插件

java 复制代码

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.OptimisticLockerInnerInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@MapperScan("com.lovejava.boot.mapper")
public class MybatisPlusConfig {

    /**
     * 添加分页插件
     */
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        //添加乐观锁插件
        interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        // 如果配置多个插件, 切记分页最后添加
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        // 如果有多数据源可以不配具体类型, 否则都建议配上具体的 DbType
        return interceptor;
    }
}

乐观锁实现

java 复制代码

    @Test
    public void testOptimisticLocker2(){

        // 线程1
        //1.查询用户信息
        User user1 = userMapper.selectById(2);
        //2.修改用户信息
        user1.setName("马超1");
        user1.setAge(20);
        user1.setEmail("machao1@qq.com");

        //模拟另外一个线程执行了插队操作
        User user2 = userMapper.selectById(2);
        //2.修改用户信息
        user2.setName("马超2");
        user2.setAge(20);
        user2.setEmail("machao2@qq.com");
        userMapper.updateById(user2);

        //如果没有乐观锁就会覆盖插队线程的值
        //可以使用自旋锁来多次尝试提交
        userMapper.updateById(user1);
    }