Microservice system design - sub service project construction

Abstract

After the early demand analysis, model design and system architecture design , We have a clearer understanding of the overall structure of the project , The rest of the work is based on the design , Pull out the project skeleton , Fill it with flesh and blood . Build sub micro service modules in the system .

One 、 Build the skeleton of the whole project

The agreed project name is parking-project , establish Maven project ,packaging The way by pom, Used to manage all modules . stay parking-project Under the project, it is established according to the functional modules maven module subprojects . use IDE Tools . With Maven Project Form to create the parent project , Used to manage sub module functions .

You can see , The sub module will automatically parent project Set to parking-project Parent project . Because of the adoption of Spring Boot To build subprojects , Choose... Here packaging The way is jar . According to this, each sub module can be created continuously , The final result is as follows ：

Briefly introduce the functions of each module ：

1. parking-base-serv,pom project , It contains two sub modules ：parking-admin,parking-gateway.
2. parking-admin, Monitor the operation of sub projects .
3. parking-gateway, Gateway sub service , coordination JWT Implement conversation 、 Functions such as power verification .
4. parking-carwash, Car washing service , Connect park-carwash database .
5. parking-card, Points sub service , Connect park-card database .
6. parking-charging, Billing sub service , Connect parking-charging The repository
7. parking-finance, Financial sub services , Connect parking-finance The repository .
8. parking-member, Member subservices , Connect park-member The repository .
9. parking-resource, Resource sub services , Connect park-resource The repository .
10. parking-message, Message sub service , Connect park-message The repository , together with rocketmq Store message data
11. parking-common, Store common utility classes , Physical packages and so on .

Two 、 Create a member sub service

2.1 introduce spring-boot-starter-parent rely on

Each sub module is a Spring Boot project , If introduced in a sub module , It will cause a lot of repetitive work , And the version should not be maintained uniformly , Prone to multiple versions of confusion , therefore Spring Boot The version of requires global unified maintenance . Each subproject needs to be built into jar File run , The child project already depends on the configuration of the parent project , Each subproject pom.xml Files have such dependencies ：

    <parent>
        <groupId>com.mall.parking.root</groupId>
        <artifactId>parking-project</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>

If in the usual way , Reuse parent Mode introduction spring-boot-starter-parent rely on , Obviously against a single pom There is only one... In the document parent Standard of label , Compilation will fail .

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.2.2.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

To solve this problem , Here the parking-project The parent project is marked with depencyMangement Mode introduction spring-boot-starter-parent, Subprojects depend on parent The parent configuration is OK .

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring.boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

There are small partners who may propose directly in the root project pom use parent Way to introduce , The sub modules pass directly through maven Rely on it , This mode operates independently Spring Boot There is no problem with the project . The following is introduced in the same way Spring Cloud or Spring Cloud Alibaba , One parent Labels obviously don't meet this need , use dependencyManagement Can avoid this problem .

2.2 introduce MBG plug-in unit

MBG Plug ins can be generated automatically mapper Interface 、mapper xml To configure 、 Corresponding entity classes , The main function is to develop rapidly , Eliminate unnecessary coding .

stay pom Configuration dependency in MBG Plug in for ：

<build>
    <finalName>parking-member-service</finalName>
    <plugins>
        <plugin>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-maven-plugin</artifactId>
            <version>1.4.0</version>
            <configuration>
                <!-- mybatis  Configuration files for generating code  -->
                <configurationFile>src/test/resources/generatorConfig.xml</configurationFile>
                <verbose>true</verbose>
                <overwrite>true</overwrite>
            </configuration>
        </plugin>
    </plugins>
</build>

stay src/test/resource Write to generatorConfig.xml file , To configure MBG plug-in unit Basic configuration items required .

<generatorConfiguration>
<!--  Local  mysql  Driving position  -->
  <classPathEntry location="/Users/apple/.m2/repository/mysql/mysql-connector-java/5.1.42/mysql-connector-java-5.1.42.jar" />

  <context id="mysqlTables" targetRuntime="MyBatis3">
    <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/park-member?useUnicode=true" userId="root"
                        password="root">
                        <property name="useInformationSchema" value="true"/>
    </jdbcConnection>

    <javaTypeResolver >
      <property name="forceBigDecimals" value="false" />
    </javaTypeResolver>

<!--  Generate  model  Entity class file location  -->
    <javaModelGenerator targetPackage="com.mall.parking.member.entity" targetProject="src/test/java">
      <property name="enableSubPackages" value="true" />
      <property name="trimStrings" value="true" />
    </javaModelGenerator>
<!--  Generate  mapper.xml  Profile location  -->
    <sqlMapGenerator targetPackage="mybatis.mapper"  targetProject="src/test/resources">
      <property name="enableSubPackages" value="true" />
    </sqlMapGenerator>
<!--  Generate  mapper  Interface file location  -->
    <javaClientGenerator type="XMLMAPPER" targetPackage="com.mall.parking.member.mapper"  targetProject="src/test/java">
      <property name="enableSubPackages" value="true" />
    </javaClientGenerator>

<!--  The table name corresponding to the entity class to be generated , Multiple entity classes can copy multiple copies of this configuration  -->
     <table tableName="member" domainObjectName="Member">
        <generatedKey column="tid" sqlStatement="SELECT REPLACE(UUID(), '-', '')"/>
    </table>
    <table tableName="vehicle" domainObjectName="Vehicle">
        <generatedKey column="tid" sqlStatement="SELECT REPLACE(UUID(), '-', '')"/>
    </table>
    <table tableName="month_card" domainObjectName="MonthCard">
        <generatedKey column="tid" sqlStatement="SELECT REPLACE(UUID(), '-', '')"/>
    </table>
  </context>
</generatorConfiguration>

When the configuration is complete , In the project name ” parking-member “ Right click , Select from the pop-up menu " Run As " —>" Maven build… ", stay Goals Enter the following command in the column ：

mybatis-generator:generate

After the command is executed successfully , Find the corresponding file in the corresponding directory , Then copy To src/java In the corresponding directory , then test Delete the generated files in the directory .

• 1.4 pre-release ,MBG Plug in generated xml file , It's the append mode , Instead of covering , Easy to form repeated labels .
• MBG It doesn't generate controller/service Layer related code , It needs to be done manually .

2.3 introduce Lombok, Simplify the code

Because the compilation phase will use lombok, So you need to be in IDE Install in lombok plug-in unit , To compile normally .

2.4 Log notes

If you don't want to write every time , You can annotate @sl4j To print logs .

private  final Logger logger = LoggerFactory.getLogger( The name of the class .class);

2.5 introduce MyBatis rely on

More efficient introduction MyBatis, Here the starter Way to introduce , Also at the root pom.xml Maintain component versions in files .

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

stay application.properties Set the database connection in the configuration file ,Spring Boot 2.x The default version is HikariCP As JDBC Connection pool .

mybatis.type-aliases-package=com.mall.parking.member.entity

# If it needs to be replaced  Druid  Connection pool , The following configuration items need to be added ：
#spring.datasource.type=com.alibaba.druid.pool.DruidDataSource

#use new driver replace deprecated driver:com.mysql.jdbc.Driver.
spring.datasource.driverClassName = com.mysql.cj.jdbc.Driver
spring.datasource.url = jdbc:mysql://localhost:3306/park_member?useUnicode=true&characterEncoding=utf-8
spring.datasource.username = root
spring.datasource.password = root

send mapper Interface files can be scanned by the system , Pass... In the main class @mapperscan annotation , Or directly in mapper Add... To the interface file @mapper annotation .

2.6 Test whether the framework is successful

@RestController
@RequestMapping("member")
@Slf4j
public class MemberController {

    @Autowired
    MemberService memberService;

    @RequestMapping("/list")
    public List<Member> list() {
        List<Member> members = memberService.list();
        log.debug("query member list = " + members);
        return members;
    }

}

MemberServiceImpl Implementation class

@Service
public class MemberServiceImpl implements MemberService {

    @Autowired
    MemberMapper memberMapper;

    @Override
    public List<Member> list() {
        MemberExample example = new MemberExample();
        List<Member> members = memberMapper.selectByExample(example);
        return members;
    }

}

Start project , Show success log after success ：

2019-12-30 16:45:13.496  INFO 9784 --- [           main] c.mall.parking.member.MemberApplication  : Started MemberApplication in 6.52 seconds (JVM running for 7.753)

open Postman plug-in unit , Test whether the method is normal , The operation is as follows ：

2.7 Multi environment configuration

The daily product development inevitably involves the problem of multi deployment , For example, development environment 、 Test environment 、 Production environment, etc , This requires that code deployment can meet the requirements of multiple environments . Through manual modification , Not only is it easy to make mistakes , It will also waste labor costs , Must be combined with automated builds to improve accuracy .Spring Boot Provides the basis for profile Multi environment configuration , Multiple configuration files can be added to each microservice item , Such as

1. application.properties/yml Basic public configuration
2. application-dev.properties/yml Development environment configuration
3. application-test.properties/yml Test environment configuration
4. application-pro.properties/yml Production environment configuration

In the public profile application.properties in , By configuring spring.profiles.active = dev To determine which configuration to enable , Or when starting the build package , Add commands to activate different environment configurations ： java -jar parking-member.jar --spring.profiles.active=dev thus , The first is simple Spring Boot Module construction is completed , The next step will be park-member The normal business function coding of the module can be completed .

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