[Spring Cloud Alibaba] Mybatis Plus persistence layer

1,Mybatis Plus

Mybatis Plus is a domestic persistence layer framework. It is very simple to use here. It should be in Chinese!

Mybatis Plus official website: https://baomidou.com/
Spring Cloud Alibaba integrates in the same way as Spring Boot

• No invasion: it is only enhanced without change, and its introduction will not affect the existing project, which is as smooth as silk
• Low loss: the basic CURD will be injected automatically upon startup, with basically no loss of performance and direct object-oriented operation
• Powerful crud operation: built in general Mapper and general Service, most CRUD operations of a single table can be realized only through a small number of configurations, and there is a powerful condition constructor to meet various use requirements
• Support Lambda formal call: it is convenient to write various query conditions through Lambda expression, and there is no need to worry about wrong fields
• Support automatic generation of primary key: support up to 4 primary key policies (including distributed unique ID generator - Sequence), which can be configured freely and - perfectly solve the primary key problem
• Support ActiveRecord mode: support ActiveRecord formal calls. Entity classes only need to inherit Model classes to perform powerful CRUD operations
• Support custom global general operations: support global general method injection (Write once, use anywhere)
• Built in code generator: code or Maven plug-in can be used to quickly generate Mapper, Model, Service and Controller layer code, support template engine, and more custom configurations for you to use
• Built in paging plug-in: Based on MyBatis physical paging, developers do not need to care about specific operations. After configuring the plug-in, writing paging is equivalent to ordinary List query
• The paging plug-in supports multiple databases: MySQL, MariaDB, Oracle, DB2, H2, HSQL, SQLite, Postgre, SQLServer and other databases
• Built in performance analysis plug-in: it can output SQL statements and their execution time. It is recommended to enable this function during development and testing to quickly find out slow queries
• Built in global interception plug-in: it provides intelligent analysis and blocking of full table delete and update operations, and can also customize interception rules to prevent misoperation

2. Integrated Mybatis Plus

Create the spring cloud Alibaba mybatis plus module and introduce related dependencies. It is no different from other modules. It is also registered in Nacos

${mybatis-plus-boot-starter.version}
${lombok.version}

Version is

<mybatis-plus-boot-starter.version>3.4.3</mybatis-plus-boot-starter.version>
<lombok.version>1.18.20</lombok.version>

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

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

        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>

        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>${mybatis-plus-boot-starter.version}</version>
        </dependency>

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

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>${lombok.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

Modify application yml configuration file, in order to facilitate writing, the yml format is used here

# Application configuration
server:
  port: 8006

# Endpoint monitoring
management:
  endpoint:
    health:
      show-details: always
  endpoints:
    jmx:
      exposure:
        include: '*'
    web:
      exposure:
        include: '*'
  server:
    port: 9006

spring:
  # apply name
  application:
    name: spring-cloud-alibaba-gateway
  # data source
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/spring-cloud-alibaba-learn?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&useSSL=false&allowPublicKeyRetrieval=true
    username: root
    password: 123456
  jackson:
    date-format: yyyy-MM-dd HH:mm:ss
    time-zone: GMT+8
    serialization:
      write-dates-as-timestamps: false
  # Nacos configuration
  cloud:
    nacos:
      discovery:
        namespace: sandbox-configuration
        password: nacos
        server-addr: localhost:8848
        username: nacos

# MybatisPlus configuration
mybatis-plus:
  configuration:
    map-underscore-to-camel-case: true
    auto-mapping-behavior: full
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  mapper-locations: classpath*:mapper/**/*Mapper.xml
  global-config:
    # Logical delete configuration
    db-config:
      # Before deletion
      logic-not-delete-value: 1
      # After deletion
      logic-delete-value: 2

Start class addition

@EnableDiscoveryClient

Create control layer

package cn.tellsea.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * User table front end controller
 *
 * @author Tellsea
 * @since 2021-12-28
 */
@RestController
@RequestMapping("/userInfo")
public class UserInfoController {

}

Create interface

package cn.tellsea.service;

import cn.tellsea.entity.UserInfo;
import com.baomidou.mybatisplus.extension.service.IService;

/**
 * User table service class
 *
 * @author Tellsea
 * @since 2021-12-28
 */
public interface IUserInfoService extends IService<UserInfo> {

}

Create interface implementation class

package cn.tellsea.service.impl;

import cn.tellsea.entity.UserInfo;
import cn.tellsea.mapper.UserInfoMapper;
import cn.tellsea.service.IUserInfoService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.stereotype.Service;

/**
 * User table service implementation class
 *
 * @author Tellsea
 * @since 2021-12-28
 */
@Service
public class UserInfoServiceImpl extends ServiceImpl<UserInfoMapper, UserInfo> implements IUserInfoService {

}

Create Mapper

package cn.tellsea.mapper;

import cn.tellsea.entity.UserInfo;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;

/**
 * Mapper Interface
 *
 * @author Tellsea
 * @since 2021-12-28
 */
public interface UserInfoMapper extends BaseMapper<UserInfo> {

}

Under resources/mapper, create mapper xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="cn.tellsea.mapper.UserInfoMapper">

    <!-- custom SQL -->

</mapper>

Create unit test

package cn.tellsea;

import cn.tellsea.entity.UserInfo;
import cn.tellsea.service.IUserInfoService;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

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

/**
 * unit testing 
 *
 * @author Tellsea
 * @date 2021/12/28
 */
@SpringBootTest
class SpringCloudAlibabaMybatisPlusApplicationTests {

    @Autowired
    private IUserInfoService userInfoService;

    @Test
    void contextLoads() {
    }

    @Test
    public void test() {
        UserInfo entity = new UserInfo();
        List<UserInfo> userInfoList = new ArrayList<>();

        // newly added
        userInfoService.save(entity);

        // Batch add
        userInfoService.saveBatch(userInfoList);

        // Update by ID
        userInfoService.updateById(entity);

        // Batch update by ID
        userInfoService.updateBatchById(userInfoList);

        // Delete by ID
        userInfoService.removeById(entity.getId());

        // Query all
        userInfoService.list();

        // Condition query
        userInfoService.list(new LambdaQueryWrapper<UserInfo>()
                .like(UserInfo::getUserName, entity.getUserName()));
    }

}

These codes can be generated at one time through the code generator of Mybatis Plus. This article mainly explains that the use of Mybatis Plus in spring cloud Alibaba is the same as that in Spring Boot. The code generator of Mybatis Plus will be updated in the corresponding module, and specify the use method and customized template

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