SpringBoot 2.x 实战仿B站高性能后端项目吾爱分享

创建一个SpringBoot项目

导入依赖

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.3.4.RELEASE
         
    
    com.example
    mybatis-plus
    0.0.1-SNAPSHOT
    mybatis-plus
    
        1.8
    
    
        
            org.springframework.boot
            spring-boot-starter
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
        
            org.springframework.boot
            spring-boot-configuration-processor
        
        
            com.baomidou
            mybatis-plus-boot-starter
            3.4.2
        
        
            mysql
            mysql-connector-java
            runtime
        
        
            org.projectlombok
            lombok
        
    
    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

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配置数据库

# application.yml
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/yogurt?serverTimezone=Asia/Shanghai
    username: root
    password: root
    
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #开启SQL语句打印
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创建一个实体类

package com.example.mp.po;
import lombok.Data;
import java.time.LocalDateTime;
@Data
public class User {
	private Long id;
	private String name;
	private Integer age;
	private String email;
	private Long managerId;
	private LocalDateTime createTime;
}
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创建一个mapper接口

package com.example.mp.mappers;
import com.baomidou.mybatisplus.core.mapper.baseMapper;
import com.example.mp.po.User;
public interface UserMapper extends baseMapper { }
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在SpringBoot启动类上配置mapper接口的扫描路径

package com.example.mp;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("com.example.mp.mappers")
public class MybatisPlusApplication {
	public static void main(String[] args) {
		SpringApplication.run(MybatisPlusApplication.class, args);
	}
}
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在数据库中创建表

DROP TABLE IF EXISTS user;
CREATE TABLE user (
id BIGINT(20) PRIMARY KEY NOT NULL COMMENT '主键',
name VARCHAr(30) DEFAULT NULL COMMENT '姓名',
age INT(11) DEFAULT NULL COMMENT '年龄',
email VARCHAr(50) DEFAULT NULL COMMENT '邮箱',
manager_id BIGINT(20) DEFAULT NULL COMMENT '直属上级id',
create_time DATETIME DEFAULT NULL COMMENT '创建时间',
ConSTRAINT manager_fk FOREIGN KEY(manager_id) REFERENCES user (id)
) ENGINE=INNODB CHARSET=UTF8;

INSERT INTO user (id, name, age ,email, manager_id, create_time) VALUES
(1, '大BOSS', 40, 'boss@baomidou.com', NULL, '2021-03-22 09:48:00'),
(2, '李经理', 40, 'boss@baomidou.com', 1, '2021-01-22 09:48:00'),
(3, '黄主管', 40, 'boss@baomidou.com', 2, '2021-01-22 09:48:00'),
(4, '吴组长', 40, 'boss@baomidou.com', 2, '2021-02-22 09:48:00'),
(5, '小菜', 40, 'boss@baomidou.com', 2, '2021-02-22 09:48:00')
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编写一个SpringBoot测试类

package com.example.mp;
import com.example.mp.mappers.UserMapper;
import com.example.mp.po.User;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import java.util.List;
import static org.junit.Assert.*;
@RunWith(SpringRunner.class)
@SpringBootTest
public class SampleTest {
	@Autowired
	private UserMapper mapper;
	@Test
	public void testSelect() {
		List list = mapper.selectList(null);
		assertEquals(5, list.size());
		list.forEach(System.out::println);
	}
}