在引入相关数据库持久化相关依赖库之前，我们可以考虑到，当我们因业务开发需要，引入各种各样的依赖库时，Jar包冲突是我们必须面对的一个问题，Spring为了解决这些Jar包的冲突，推出了各种bom，最著名的就是Spring IO Platform bom，其中最核心的三个是：spring-framework-bom、spring-boot-dependencies、platform-bom。我们这里参考Spring管理Jar包的方式，新建一个GitEgg-Platform平台工程，提供各种第三方组件的配置及自定义方法，使用子工程gitegg-platform-bom统一管理GitEgg自定义方法扩展jar包及第三方Jar包版本。
1、首先在GitEgg-Platform工程下新建gitegg-platform-db用于管理系统需要用到的数据库驱动、数据库连接池的jar包及配置，新建gitegg-platform-mybatis用于管理系统需要用到的持久层框架，建好的结构如下：
2、修改GitEgg-Platform根目录下的pom.xml，设置工程编码方式，及引入的Spring Boot，Spring Cloud，gitegg-platform-bom版本：
4.0.0
com.gitegg.platform
GitEgg-Platform
${project.artifactId}
1.0-SNAPSHOT
pom
gitegg-platform-bom
gitegg-platform-db
gitegg-platform-mybatis
1.8
3.8.1
UTF-8
UTF-8
UTF-8
2.3.3.RELEASE
Hoxton.SR8
Cairo-SR8
com.gitegg.platform
gitegg-platform-bom
${project.version}
pom
import
org.springframework.boot
spring-boot-dependencies
${spring.boot.version}
pom
import
org.springframework.cloud
spring-cloud-dependencies
${spring.cloud.version}
pom
import
${project.name}
src/main/resources
src/main/java
**/*.xml
org.apache.maven.plugins
maven-compiler-plugin
${maven.plugin.version}
${java.version}
${java.version}
UTF-8
-parameters
aliyun-repos
https://maven.aliyun.com/nexus/content/groups/public/
false
gitegg-release
Release Repository
https://packages.aliyun.com/maven/repository/2020515-release-dpxo1j/
aliyun-plugin
https://maven.aliyun.com/nexus/content/groups/public/
false
dev
dev
true
test
test
pro
pro
3、修改gitegg-platform-bom工程下的pom.xml，引入目前需要的数据库驱动，数据连接池及Mybatis-Plus：
org.springframework.boot
spring-boot-starter-parent
2.3.3.RELEASE
4.0.0
com.gitegg.platform
gitegg-platform-bom
${project.artifactId}
${gitegg.project.version}
pom
1.8
3.8.1
UTF-8
UTF-8
UTF-8
1.0-SNAPSHOT
8.0.17
9.1-901.jdbc4
1.1.23
3.4.0
com.gitegg.platform
gitegg-platform-db
${gitegg.project.version}
com.gitegg.platform
gitegg-platform-mybatis
${gitegg.project.version}
mysql
mysql-connector-java
${mysql.connector.version}
postgresql
postgresql
${postgresql.connector.version}
com.alibaba
druid-spring-boot-starter
${druid.version}
com.baomidou
mybatis-plus-boot-starter
${mybatis.plus.version}
4、修改gitegg-platform-db工程下的pom.xml，只引入数据库驱动及数据库连接池相关jar包：
GitEgg-Platform
com.gitegg.platform
1.0-SNAPSHOT
4.0.0
gitegg-platform-db
${project.artifactId}
${project.parent.version}
jar
mysql
mysql-connector-java
postgresql
postgresql
com.alibaba
druid-spring-boot-starter
5、修改gitegg-platform-mybatis工程下的pom.xml，只引入mybatis-plus相关jar包：
GitEgg-Platform
com.gitegg.platform
1.0-SNAPSHOT
4.0.0
gitegg-platform-mybatis
${project.artifactId}
${project.parent.version}
jar
com.baomidou
mybatis-plus-boot-starter
6、pom.xml文件配置好之后，在IDEA右侧窗口，Maven中点击install，将包安装到本地，这样GitEgg-Cloud工程就可以引用GitEgg-Platform工程的jar包了，同理，测试及正式环境需要点击deploy，将jar包发布到测试的Maven私服，或者正式环境的Maven私服。
7、回到GitEgg-Cloud项目，在gitegg-service下的pom.xml里面引入gitegg-platform-db和gitegg-platform-mybatis
GitEgg-Cloud
com.gitegg.cloud
1.0-SNAPSHOT
4.0.0
gitegg-service
pom
gitegg-service-base
gitegg-service-bigdata
gitegg-service-system
com.gitegg.platform
gitegg-platform-db
com.gitegg.platform
gitegg-platform-mybatis
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-actuator
8、在gitegg-service-system工程下修改application.yml，增加数据库连接和mybatis的配置：
server:
port: 8001
spring:
application:
name: gitegg-service-system
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driverClassName: com.mysql.jdbc.Driver
url: jdbc:mysql://127.0.0.1/gitegg_cloud?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=utf8&allowMultiQueries=true&autoReconnect=true
username: root
password: root
initialSize: 1
minIdle: 3
maxActive: 20
# 配置获取连接等待超时的时间
maxWait: 60000
# 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
timeBetweenEvictionRunsMillis: 60000
# 配置一个连接在池中最小生存的时间，单位是毫秒
minEvictableIdleTimeMillis: 30000
validationQuery: select 'x'
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
# 打开PSCache，并且指定每个连接上PSCache的大小
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 20
# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
filters: config,stat,slf4j
# 通过connectProperties属性来打开mergeSql功能；慢SQL记录
connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000;
# 合并多个DruidDataSource的监控数据
useGlobalDataSourceStat: true
mybatis-plus:
mapper-locations: classpath*:/com/gitegg/*/*/mapper/*Mapper.xml
typeAliasesPackage: com.gitegg.*.*.entity
global-config:
#主键类型 0:"数据库ID自增", 1:"用户输入ID",2:"全局唯一ID (数字类型唯一ID)", 3:"全局唯一ID UUID";
id-type: 2
#字段策略 0:"忽略判断",1:"非 NULL 判断"),2:"非空判断"
field-strategy: 2
#驼峰下划线转换
db-column-underline: true
#刷新mapper 调试神器
refresh-mapper: true
#数据库大写下划线转换
#capital-mode: true
#逻辑删除配置
logic-delete-value: 1
logic-not-delete-value: 0
configuration:
map-underscore-to-camel-case: true
cache-enabled: false9、修改GitEggSystemApplication，添加要扫描的mapper路径声明：
package com.gitegg.service.system;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
/**
* gitegg-system 启动类
*/
@MapperScan("com.gitegg.*.*.mapper")
@SpringBootApplication
public class GitEggSystemApplication {
public static void main(String[] args) {
SpringApplication.run(GitEggSystemApplication.class,args);
}
}
10、修改GitEgg-Platform工程中的gitegg-platform-db和gitegg-platform-mybatis，新增mybatis-plus分页配置，和Druid数据库连接配置，此配置类预留，后面需要自定义修改。
DruidConfig.java内容如下:
package com.gitegg.platform.db.config; import org.springframework.context.annotation.Configuration; @Configuration public class DruidConfig { }MybatisPlusConfig.java内容如下:
package com.gitegg.platform.mybatis.config; import com.baomidou.mybatisplus.annotation.DbType; import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor; 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.gitegg.**.mapper.**") public class MybatisPlusConfig { /** * 新的分页插件,一缓和二缓遵循mybatis的规则,需要设置 MybatisConfiguration#useDeprecatedExecutor = false * 避免缓存出现问题(该属性会在旧插件移除后一同移除) */ @Bean public MybatisPlusInterceptor mybatisPlusInterceptor() { MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor(); interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL)); return interceptor; } }11、增加测试类，通过访问controller->service->dao层，获取数据库数据。新建controller、service、impl、mapper、entity、dto包，这些包和类，后面可以用系统自动生成，不需要每次都自己手动建立。
SystemController.java文件内容：
package com.gitegg.service.system.controller; import com.gitegg.service.system.service.ISystemService; import lombok.AllArgsConstructor; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestController @RequestMapping(value = "system") @AllArgsConstructor public class SystemController { private final ISystemService systemService; @GetMapping(value = "list") public Object list() { return systemService.list(); } @GetMapping(value = "page") public Object page() { return systemService.page(); } }ISystemService.java文件内容：
package com.gitegg.service.system.service; import com.baomidou.mybatisplus.extension.plugins.pagination.Page; import com.gitegg.service.system.entity.SystemTable; import java.util.List; public interface ISystemService { Listlist(); Page page(); } SystemServiceImpl.java 内容：
package com.gitegg.service.system.service.impl; import com.baomidou.mybatisplus.extension.plugins.pagination.Page; import com.gitegg.service.system.entity.SystemTable; import com.gitegg.service.system.mapper.SystemTableMapper; import com.gitegg.service.system.service.ISystemService; import lombok.AllArgsConstructor; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import java.util.List; /** * */ @Service @AllArgsConstructor public class SystemServiceImpl implements ISystemService { private final SystemTableMapper systemTableMapper; @Override public Listlist() { return systemTableMapper.list(); } @Override public Page page() { Page page = new Page<>(1, 10); List records = systemTableMapper.page(page); page.setRecords(records); return page; } } SystemTableMapper.java内容：
package com.gitegg.service.system.mapper; import com.baomidou.mybatisplus.extension.plugins.pagination.Page; import com.gitegg.service.system.entity.SystemTable; import org.apache.ibatis.annotations.Mapper; import java.util.List; @Mapper public interface SystemTableMapper { Listlist(); List page(Page page); } SystemTable.java内容：
package com.gitegg.service.system.entity; import lombok.Data; @Data public class SystemTable { private Long id; private String name; }SystemTableMapper.xml内容：
12、运行GitEggSystemApplication，在控制台看是否启动成功，如果启动成功，在浏览器中分别访问http://127.0.0.1:8001/system/...和http://127.0.0.1:8001/system/...，可以看到数据里面的数据：
本文源码在https://gitee.com/wmz1930/GitEgg的chapter-05分支。