Micronaut微服务 实战入门

Your story may not have a happy beginning, but that doesn’t make you who you are, it is restof your story, who you choose to be.

你或许没有一个幸福的开始，但是这并不能够代表你的所有，接下来你的生活取决于你的选择。——《功夫熊猫2》

基本概述

既然决定去做一件事情，就好比把自己铺成一张稿纸，不论是信笔涂鸦还是书写酣畅，就尽情去享受和体验就好。每一进步一点，天道酬勤，谁都会是大赢家。尽管是在这个尴尬的二十几岁，正是应该丰富自己和提升自己的时候，去经历一些非议，成长才会更快。就像是缓存清零，重新启动，一切还是原来模样……在基础入门篇时候，简单概述了Micronaut配置操作。接下来，针对于这一方面做更近一步的学习。比如，在开发工具方面的配置，在Micronaut相关命令和API的运用，创建完Demo工程的项目结构解析以及项目构建等。

开发IDE配置

Micronaut开发工具有IntelliJ IDEA ,Eclipse,Visual Studio Code三种。

IntelliJ IDEA配置

[1].增加Micronaut插件IntelliJ IDEA配置

[2].对于Maven 和Gradle工具的配置:

创建项目工程

• Micronaut CLI Project Creation Commands：

Command	Description	Options	Example
create-app	Creates a basic Micronaut application	-p Command Flags	mn create-app my-project –features mongo-reactive,security-jwt –build maven
create-cli-app	Creates a command-line Micronaut application.	-p Command Flags	mn create-cli-app my-project –features http-client,jdbc-hikari –build maven –lang kotlin –test kotest
create-function-app	Creates a Micronaut serverless function, using AWS by default.	-p Command Flags	mn create-function-app my-lambda-function –lang groovy –test spock
create-messaging-app	Creates a Micronaut application that only communicates via a messaging protocol. Uses Kafka by default but can be switched to RabbitMQ with –features rabbitmq.	-p Command Flags	mn create-function-app my-lambda-function –lang groovy –test spock
create-grpc-app	Creates a Micronaut application that uses gRPC.	-p Command Flags	mn create-grpc-app my-grpc-app –lang groovy –test spock

[⚠️注意事项]：
Micronaut创建工程支持的模板如下：
create-app：创建Micronaut基础应用程序
create-cli-app:创建Micronaut命令行应用程序
create-function-app:创建Micronaut函数应用程序，默认使用AWS
create-messaging-app:创建Micronaut消息队列应用程序，默认使用Kafka
create-grpc-app:创建Micronaut分布式GRPC应用程序

• Create Command Flags:

Flag	Description	Example
-l, –lang	Language to use for the project (one of java, groovy, kotlin - default is java)	–lang groovy
-t, –test	Test framework to use for the project (one of junit, spock - default is junit)	–test spock
-b,–build	Build tool (one of gradle, gradle_kotlin, maven - default is gradle for the languages java and groovy; default is gradle_kotlin for language kotlin)	–build maven
-f,–features	Features to use for the project, comma-separated	–features security-jwt,mongo-gorm
-i,–inplace	If present, generates the project in the current directory (project name is optional if this flag is set)	–inplace

[⚠️注意事项]：
Micronaut创建工程支持的参数如下：
–lang：支持java, groovy, kotlin语言
–test:支持junit, spock测试框架
–build:支持gradle, gradle_kotlin, maven构建工具
–features:支持众多第三方框架
–inplace：支持替换参数

在本地工程目录:/Users/Projects/GitlabCloud/pandora-cloud-platform中:

shell复制代码MacBook-Pro:pandora-cloud-platform root$ cd /Users/Projects/GitlabCloud/pandora-cloud-platform
MacBook-Pro:pandora-cloud-platform root$ ls
LICENSE				pandora-cloud-gateway
README.en.md			pandora-cloud-model
README.md			pandora-cloud-platform.iml
pandora-cloud-console		pandora-cloud-program
pandora-cloud-core		pandora-cloud-schedule
pandora-cloud-dependencies	pom.xml
pandora-cloud-framework
MacBook-Pro:pandora-cloud-platform root$

输入：mn create-app com.pandora-cloud-monitor –build maven –lang=java

shell复制代码MacBook-Pro:pandora-cloud-platform root$ mn create-app com.pandora-cloud-monitor --build maven --lang=java
| Generating Java project...
| Application created at /Users/Projects/GitlabCloud/pandora-cloud-platform/pandora-cloud-monitor
MacBook-Pro:pandora-cloud-platform root$

工程结构

项目工程机构如下：

• .gitignore：分布式版本控制系统git的配置文件，意思为忽略提交
  在 .gitingore 文件中，遵循相应的语法，即在每一行指定一个忽略规则。 如：.log、/target/、.idea
• mvnw：全名是maven wrapper的文件
  它的作用是在maven-wrapper.properties文件中记录你要使用的maven版本，当用户执行mvnw clean 命令时，发现当前用户的maven版本和期望的版本不一致，那么就下载期望的版本，然后用期望的版本来执行mvn命令，比如mvn clean命令。
• mvn文件夹：存放mvnw相关文件
  存放着maven-wrapper.properties和相关jar包以及名为MavenWrapperDownloader的java文件
• mvn.cmd：执行mvnw命令的cmd入口
  注：mvnw文件适用于Linux（bash），mvnw.cmd适用于Windows 环境。
• pom.xml：项目对象模型

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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>pandora.cloud.generator</groupId>
  <artifactId>pandora-cloud-generator</artifactId>
  <version>0.1</version>
  <properties>
    <micronaut.version>1.2.6</micronaut.version>
    <jdk.version>1.8</jdk.version>
    <maven.compiler.target>${jdk.version}</maven.compiler.target>
    <maven.compiler.source>${jdk.version}</maven.compiler.source>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <exec.mainClass>pandora.cloud.generator.Application</exec.mainClass>
    <maven-surefire-plugin.version>2.22.2</maven-surefire-plugin.version>
    <maven-failsafe-plugin.version>2.22.2</maven-failsafe-plugin.version>
  </properties>
  <repositories>
    <repository>
      <id>jcenter.bintray.com</id>
      <url>https://jcenter.bintray.com</url>
    </repository>
  </repositories>
  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>io.micronaut</groupId>
        <artifactId>micronaut-bom</artifactId>
        <version>${micronaut.version}</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>
  </dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>io.micronaut</groupId>
      <artifactId>micronaut-inject</artifactId>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>io.micronaut</groupId>
      <artifactId>micronaut-validation</artifactId>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>io.micronaut</groupId>
      <artifactId>micronaut-runtime</artifactId>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>io.micronaut</groupId>
      <artifactId>micronaut-http-server-netty</artifactId>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>io.micronaut</groupId>
      <artifactId>micronaut-http-client</artifactId>
      <scope>compile</scope>
    </dependency>
    <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-classic</artifactId>
      <version>1.2.3</version>
      <scope>runtime</scope>
    </dependency>
    <dependency>
      <groupId>org.junit.jupiter</groupId>
      <artifactId>junit-jupiter-api</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.junit.jupiter</groupId>
      <artifactId>junit-jupiter-engine</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>io.micronaut.test</groupId>
      <artifactId>micronaut-test-junit5</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>3.1.0</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
            <configuration>
              <transformers>
                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                  <mainClass>${exec.mainClass}</mainClass>
                </transformer>
                <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
              </transformers>
            </configuration>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.6.0</version>
        <configuration>
          <executable>java</executable>
          <arguments>
            <argument>-classpath</argument>
            <classpath/>
            <argument>-noverify</argument>
            <argument>-XX:TieredStopAtLevel=1</argument>
            <argument>-Dcom.sun.management.jmxremote</argument>
            <argument>${exec.mainClass}</argument>
          </arguments>
        </configuration>
      </plugin>
    </plugins>
    <pluginManagement>
      <plugins>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>${maven-surefire-plugin.version}</version>
          <configuration>
            <detail>true</detail>
            <includes>
              <include>%regex[.*]</include>
            </includes>
          </configuration>
        </plugin>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-failsafe-plugin</artifactId>
          <version>${maven-failsafe-plugin.version}</version>
          <executions>
            <execution>
              <goals>
                <goal>integration-test</goal>
                <goal>verify</goal>
              </goals>
            </execution>
          </executions>
        </plugin>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.7.0</version>
          <configuration>
            <compilerArgs>
              <arg>-parameters</arg>
            </compilerArgs>
            <annotationProcessorPaths>
                  <path>
                    <groupId>io.micronaut</groupId>
                    <artifactId>micronaut-inject-java</artifactId>
                    <version>1.2.6</version>
                  </path>
                  <path>
                    <groupId>io.micronaut</groupId>
                    <artifactId>micronaut-validation</artifactId>
                    <version>1.2.6</version>
                  </path>
            </annotationProcessorPaths>
          </configuration>
          <executions>
            <execution>
              <id>test-compile</id>
              <goals>
                <goal>testCompile</goal>
              </goals>
              <configuration>
                <compilerArgs>
                  <arg>-parameters</arg>
                </compilerArgs>
                <annotationProcessorPaths>
                  <path>
                    <groupId>io.micronaut</groupId>
                    <artifactId>micronaut-inject-java</artifactId>
                    <version>1.2.6</version>
                  </path>
                  <path>
                    <groupId>io.micronaut</groupId>
                    <artifactId>micronaut-validation</artifactId>
                    <version>1.2.6</version>
                  </path>
                </annotationProcessorPaths>
              </configuration>
            </execution>
          </executions>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

pom.xml主要描述了项目的maven坐标，依赖关系，开发者需要遵循的规则，缺陷管理系统，组织和licenses，以及其他所有的项目相关因素，是项目级别的配置文件。

• src：存放开发代码和资源目录
  
• Dockerfile :构建Docker镜像的配置文件

yml复制代码FROM adoptopenjdk/openjdk11-openj9:jdk-11.0.1.13-alpine-slim
COPY target/pandora-cloud-generator-*.jar pandora-cloud-generator.jar
EXPOSE 8080
CMD java -Dcom.sun.management.jmxremote -noverify ${JAVA_OPTS} -jar pandora-cloud-generator.jar

• micronaut-cli.yml：micronaut 应用的配置文件

yml复制代码profile: service
defaultPackage: pandora.cloud.generator
---
testFramework: junit
sourceLanguage: java

项目启动

Micronaut应用程序的启动方式和Springboot应用启动一样，通过调用Micronaut.run来实现：

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本文转载自: 掘金

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