微服务

微服务架构师当前软件开发领域的技术热点。它在各种博客、社交媒体和会议演讲上的出镜率非常之高。大家以前可能或多或少听说过些许。然而微服务似乎又是非常虚幻的————我们找不到微服务的完整定义，以至于很多人认为这是一个概念的炒作。

一般讲到微服务架构，都会提到单体应用。首先来说说单体应用：

 

一个归档包（比如 war 包）包含的所有功能的应用程序。在项目中我们通常将需求分为三个主要部分：数据库、服务端处理、前端展现。在业务发展初期，由于所有的业务逻辑在一个应用中，开发、测试、部署都还比较容易且方便。这种通常称为单体应用。这也就是现在称之为单体应用架构的方法论

 

尽管该应用已经进行了模块化，但由于 UI 和若干业务模块最终都被打包在同一个 War 包中，改 war 包包含了整个系统所有的业务功能，这样的应用系统成为单体应用。 相信很多项目都是从单体应用开始的。单体应用比较容易部署、测试，在项目初期，单体应用可以很好地稳定运行。然而，一般项目都会随着需求而不断的变化以及增加，越来越多的人加入到项目的开发团队，代码库也在飞速地膨胀。慢慢地，单体应用变得越来越臃肿，可维护性、灵活性逐渐降低，维护成本越来越高。

 

微服务架构风格是一种将一个单体应用程序开发为一组小行服务的方法，每个服务运行在自己的进程中，服务间通信采用轻量级通信机制（通常用 HTTP 资源 API）。这些服务围绕业务能力构建摒弃人可通过全自动部署机制独立部署。这些服务共用一个最小型的集中式的管理，服务可用不同的语言开发，使用不同的数据存储技术。——引自 Martin Fowler 的博客

 

 

  • 每个微服务可独立运行在自己的进程里，做到了进程隔离。
  • 一系列独立运行的微服务共同构建起整个系统。
  • 每个服务为独立的业务开发，一个微服务只关注某个特定的功能，例如订单管理、用户管理等。
  • 微服务之间通过一些轻量级的通信机制进行通信，例如通过 RESTful API 进行调用。
  • 可以使用不同的语言与数据库存储技术。
  • 全自动的部署机制。

 

 

 

 

 

 

开始进入真正的主角介绍，Spring Cloud开发框架。

Spring Cloud 是一个用于构建分布式系统的通用模块的工具集。

 

 

  • 约定优于配置
  • 适用于各种环境
  • 隐藏了组件的复杂性
  • 开箱即用
  • 轻量级的组件
  • 丰富的组件，比如：服务发现、断路器、微服务网关等，后面实验将会一一介绍。
  • 灵活，Spring Cloud 的组成是解耦的，开发人员可按需灵活挑选组合。

更多关于 Spring Cloud 的信息可以去官网查看：spring.io。

 

从这节开始我们真正开始实战微服务架构。首先 Spring Cloud 并不是面向零基础的开发人员，假设你现在已经熟悉 Java 基础和 Spring Boot 基础。

之前讲到过，Spring Cloud 是用于构建分布式系统的，一般分布式系统都会涉及到服务提供者和服务消费者。 本实验就开始试着构建一个用户服务提供者和一个电影服务消费者。

 

以电影售票系统为例。如图，用户向电影微服务发起了一个购票的请求。在进行购票的业务操作前，电影微服务需要调用用户微服务的接口，查询当前用户的余额是多少、是不是符合购票标准等。在这种场景下，用户微服务就是一个服务提供者，电影微服务则是一个服务消费者。

图片描述

知识点

  • 分布式系统的大致组成
  • 服务提供者和消费者的关系
  • 通过 Maven 引用 Spring Cloud 依赖
  • 通过 Spring Cloud 编写微服务

工具及软件

  • JDK：建议使用 JDK 1.8
  • Spring Boot：实验使用 Spring Boot 2.0.7.RELEASE 版本。
  • Spring Cloud：实验使用 Spring Cloud Finchley.SR2 版本。
  • Maven：实验使用 Maven 3.6.0 构建项目。
 
 Spring Boot/Spring Cloud 时代后，应用开发基本遵循三板斧：加依赖、加注解、写配置。至于你的业务代码原来怎么写还是怎么写。 如果你不太清楚如何创建脚手架，可以通过 Spring Initilizr（start.spring.io，网页版）在线生成。
 
 

创建微服务项目

C:\Users\l>mvn -version
Apache Maven 3.6.3 (cecedd3430 02696d0abb50b32b541b8a6ba2883f)
Maven home: E:\kaifa\apache-maven-3.6.3-bin\apache-maven-3.6.3\bin\..
Java version: 1.8.0_111, vendor: Oracle Corporation, runtime: D:\kaifa\java\jdk\jre
Default locale: zh_CN, platform encoding: GBK
OS name: "windows 10", version: "10.0", arch: "amd64", family: "windows"

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

maven pom 仓库



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<?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>com.lzj1234</groupId>
    <artifactId>microservice-provider-user</artifactId>
    <version>1.0-SNAPSHOT</version>
 
    <properties>
        <java.version>1.8</java.version>
    </properties>
 
    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-data-jpa -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
            <version>2.4.2</version>
        </dependency>
 
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.4.2</version>
        </dependency>
 
        <!-- 引入H2数据库，一种内嵌的数据库，语法类似MySQL -->
        <!-- https://mvnrepository.com/artifact/com.h2database/h2 -->
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <version>1.4.200</version>
<!--            <scope>test</scope>-->
        </dependency>
 
        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.18</version>
            <scope>provided</scope>
        </dependency>
 
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-test -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <version>2.4.2</version>
            <scope>test</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.maven.plugins/maven-clean-plugin -->
        <dependency>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-clean-plugin</artifactId>
            <version>2.5</version>
        </dependency>
 
    </dependencies>
 
    <!-- 引入spring cloud的依赖，不能少，主要用来管理Spring Cloud生态各组件的版本 -->
    <dependencyManagement>
        <dependencies>
            <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-dependencies -->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.SR10</version>
                <type>pom</type>
                <scope>runtime</scope>
            </dependency>
 
 
        </dependencies>
    </dependencyManagement>
 
<!--    <build>-->
<!--        <plugins>-->
<!--            <!– 添加spring-boot的maven插件，不能少，打jar包时得用 –>-->
<!--            <plugin>-->
<!--                <groupId>org.springframework.boot</groupId>-->
<!--                <artifactId>spring-boot-maven-plugin</artifactId>-->
<!--                <version>2.4.2</version>-->
<!--            </plugin>-->
<!--        </plugins>-->
<!--    </build>-->
    <build>
 
        <plugins>
            <!-- 添加spring-boot的maven插件，不能少，打jar包时得用 -->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.4.2</version>
            </plugin>
            <plugin>
 
                <!-- https://mvnrepository.com/artifact/org.apache.maven.plugins/maven-compiler-plugin -->
 
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.5.1</version>
 
 
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
 
    </build>
</project>

　　

maven setttings配置

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  <mirror>
    <id>aliyunmaven</id>
    <mirrorOf>*</mirrorOf>
    <name>阿里云公共仓库</name>
    <url>https://maven.aliyun.com/repository/public</url>
</mirror>
 
 <mirror>
    <id>aliyunmaven2</id>
    <mirrorOf>*</mirrorOf>
    <name>阿里云公共仓库</name>
    <url>http://repository.apache.org/content/groups/snapshots/?spm=a2c40.maven_devops2020_goldlog_.0.0.43643054AxL62v/</url>
</mirror>

　　不添加这个mirror镜像：

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http://repository.apache.org/content/groups/snapshots/?spm=a2c40.maven_devops2020_goldlog_.0.0.43643054AxL62v/<br>就会报这个错

 Could not transfer metadata org.codehaus.mojo/maven-metadata.xml from/to rep

 

运行

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C:\Users\l\javademo\microservice-provider-user>mvn spring-boot:run
[INFO] Scanning for projects...
[INFO]
[INFO] ---------------< com.lzj1234:microservice-provider-user >---------------
[INFO] Building microservice-provider-user 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] >>> spring-boot-maven-plugin:2.4.2:run (default-cli) > test-compile @ microservice-provider-user >>>
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ microservice-provider-user ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 1 resource
[INFO]
[INFO] --- maven-compiler-plugin:2.5.1:compile (default-compile) @ microservice-provider-user ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ microservice-provider-user ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:2.5.1:testCompile (default-testCompile) @ microservice-provider-user ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] <<< spring-boot-maven-plugin:2.4.2:run (default-cli) < test-compile @ microservice-provider-user <<<
[INFO]
[INFO]
[INFO] --- spring-boot-maven-plugin:2.4.2:run (default-cli) @ microservice-provider-user ---
[INFO] Attaching agents: []
 
  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.4.2)
 
2021-02-18 23:56:10.859  INFO 18084 --- [           main] com.src.App                              : Starting App using Java 1.8.0_111 on DESKTOP-SRVQTV7 with PID 18084 (C:\Users\l\j
avademo\microservice-provider-user\target\classes started by l in C:\Users\l\javademo\microservice-provider-user)
2021-02-18 23:56:10.863  INFO 18084 --- [           main] com.src.App                              : No active profile set, falling back to default profiles: default
2021-02-18 23:56:11.446  INFO 18084 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2021-02-18 23:56:11.496  INFO 18084 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 42 ms. Found 1 JPA repository interfa
ces.
2021-02-18 23:56:12.891  INFO 18084 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8000 (http)
2021-02-18 23:56:12.902  INFO 18084 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-02-18 23:56:12.902  INFO 18084 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.41]
2021-02-18 23:56:13.001  INFO 18084 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2021-02-18 23:56:13.001  INFO 18084 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2091 ms
2021-02-18 23:56:13.161  INFO 18084 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2021-02-18 23:56:13.266  INFO 18084 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
2021-02-18 23:56:13.312  INFO 18084 --- [           main] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [name: default]
2021-02-18 23:56:13.360  INFO 18084 --- [           main] org.hibernate.Version                    : HHH000412: Hibernate ORM core version 5.4.27.Final
2021-02-18 23:56:13.483  INFO 18084 --- [           main] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.1.2.Final}
2021-02-18 23:56:13.600  INFO 18084 --- [           main] org.hibernate.dialect.Dialect            : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
Hibernate: drop table if exists user CASCADE
Hibernate: drop sequence if exists hibernate_sequence
Hibernate: create sequence hibernate_sequence start with 1 increment by 1
Hibernate: create table user (id bigint not null, age integer, balance decimal(19,2), name varchar(255), username varchar(255), primary key (id))
2021-02-18 23:56:14.216  INFO 18084 --- [           main] o.h.e.t.j.p.i.JtaPlatformInitiator       : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jt
a.platform.internal.NoJtaPlatform]
2021-02-18 23:56:14.225  INFO 18084 --- [           main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2021-02-18 23:56:14.508  WARN 18084 --- [           main] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be
 performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2021-02-18 23:56:14.614  INFO 18084 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2021-02-18 23:56:14.793  INFO 18084 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8000 (http) with context path ''
2021-02-18 23:56:14.801  INFO 18084 --- [           main] com.src.App                              : Started App in 4.4 seconds (JVM running for 4.811)
Hibernate: select user0_.id as id1_0_0_, user0_.age as age2_0_0_, user0_.balance as balance3_0_0_, user0_.name as name4_0_0_, user0_.username as username5_0_0_ from user user0_ where
 user0_.id=?
2021-02-18 23:56:14.853 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [BIGINT] - [1]
Hibernate: call next value for hibernate_sequence
Hibernate: insert into user (age, balance, name, username, id) values (?, ?, ?, ?, ?)
2021-02-18 23:56:14.885 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [INTEGER] - [20]
2021-02-18 23:56:14.888 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [2] as [NUMERIC] - [100]
2021-02-18 23:56:14.889 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [3] as [VARCHAR] - [瀵姳绗乚
2021-02-18 23:56:14.890 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [4] as [VARCHAR] - [account1]
2021-02-18 23:56:14.891 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [5] as [BIGINT] - [1]
Hibernate: select user0_.id as id1_0_0_, user0_.age as age2_0_0_, user0_.balance as balance3_0_0_, user0_.name as name4_0_0_, user0_.username as username5_0_0_ from user user0_ where
 user0_.id=?
2021-02-18 23:56:14.899 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [BIGINT] - [2]
Hibernate: call next value for hibernate_sequence
Hibernate: insert into user (age, balance, name, username, id) values (?, ?, ?, ?, ?)
2021-02-18 23:56:14.901 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [INTEGER] - [28]
2021-02-18 23:56:14.902 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [2] as [NUMERIC] - [180]
2021-02-18 23:56:14.902 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [3] as [VARCHAR] - [閺夊骸娲揮
2021-02-18 23:56:14.903 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [4] as [VARCHAR] - [account2]
2021-02-18 23:56:14.905 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [5] as [BIGINT] - [2]
Hibernate: select user0_.id as id1_0_0_, user0_.age as age2_0_0_, user0_.balance as balance3_0_0_, user0_.name as name4_0_0_, user0_.username as username5_0_0_ from user user0_ where
 user0_.id=?
2021-02-18 23:56:14.907 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [BIGINT] - [3]
Hibernate: call next value for hibernate_sequence
Hibernate: insert into user (age, balance, name, username, id) values (?, ?, ?, ?, ?)
2021-02-18 23:56:14.909 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [INTEGER] - [32]
2021-02-18 23:56:14.909 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [2] as [NUMERIC] - [280]
2021-02-18 23:56:14.910 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [3] as [VARCHAR] - [閻滃绨瞉
2021-02-18 23:56:14.910 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [4] as [VARCHAR] - [account3]
2021-02-18 23:56:14.910 TRACE 18084 --- [           main] o.h.type.descriptor.sql.BasicBinder      : binding parameter [5] as [BIGINT] - [3]
2021-02-18 23:56:44.092  INFO 18084 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
2021-02-18 23:56:44.093  INFO 18084 --- [extShutdownHook] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default'
2021-02-18 23:56:44.094  INFO 18084 --- [extShutdownHook] .SchemaDropperImpl$DelayedDropActionImpl : HHH000477: Starting delayed evictData of schema as part of SessionFactory shut-do
wn'
Hibernate: drop table if exists user CASCADE
Hibernate: drop sequence if exists hibernate_sequence
2021-02-18 23:56:44.099  INFO 18084 --- [extShutdownHook] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2021-02-18 23:56:44.101  INFO 18084 --- [extShutdownHook] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  35.701 s
[INFO] Finished at: 2021-02-18T23:56:44+08:00
[INFO] ------------------------------------------------------------------------
终止批处理操作吗(Y/N)? y

　　

测试

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C:\Users\l\javademo\microservice-provider-user>curl http://localhost:8000/users/1
{"id":1,"username":"account1","name":"瀵姳绗?,"age":20,"balance":100.00}

　　

 

 

消费者

pom.xml

 

<?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>com.shiyanlou</groupId>
    <artifactId>microservice-consumer-movie</artifactId>
    <version>1.0-SNAPSHOT</version>

<!--    <properties>-->
<!--        <maven.compiler.source>8</maven.compiler.source>-->
<!--        <maven.compiler.target>8</maven.compiler.target>-->
<!--    </properties>-->
    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-data-jpa -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
            <version>2.4.2</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.4.2</version>
        </dependency>

        <!-- 引入H2数据库，一种内嵌的数据库，语法类似MySQL -->
        <!-- https://mvnrepository.com/artifact/com.h2database/h2 -->
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <version>1.4.200</version>
            <!--            <scope>test</scope>-->
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.18</version>
            <scope>provided</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-test -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <version>2.4.2</version>
            <scope>test</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.maven.plugins/maven-clean-plugin -->
        <dependency>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-clean-plugin</artifactId>
            <version>2.5</version>
        </dependency>

    </dependencies>

    <!-- 引入spring cloud的依赖，不能少，主要用来管理Spring Cloud生态各组件的版本 -->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Finchley.SR2</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.4.2</version>
            </plugin>
            <plugin>

                <!-- https://mvnrepository.com/artifact/org.apache.maven.plugins/maven-compiler-plugin -->

                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.5.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>


</project>

　　

 user.java

?
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package com.shiyanlou;<br><br>import lombok.AllArgsConstructor;<br>import lombok.Data;<br>import lombok.NoArgsConstructor;<br><br>import java.math.BigDecimal;<br><br>@Data<br>@AllArgsConstructor<br>@NoArgsConstructor<br>public class User {<br>    private Long id;<br>    private String username;<br>    private String name;<br>    private Integer age;<br>    private BigDecimal balance;<br>}}

　　app.java

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package com.shiyanlou;
 
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
 
 
@SpringBootApplication
public class App {
 
    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
 
    @Bean
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
}

　　

 

MovieController.java

 

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package com.shiyanlou;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
 
@RequestMapping("/movies")
@RestController
public class MovieController {
 
    @Autowired
    RestTemplate restTemplate;
 
    @GetMapping("/users/{id}")
    public User findById(@PathVariable Long id){
        User user=this.restTemplate.getForObject("http://localhost:8000/users/{id}",User.class,id);
        return user;
    }
}

　配置

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server:
  port: 8010
spring:
  application:
    name: microservice-consumer-movie
logging:
  level:
    root: INFO
    # 配置日志级别，让hibernate打印出执行的SQL参数
    org.hibernate: INFO
    org.hibernate.type.descriptor.sql.BasicBinder: TRACE
    org.hibernate.type.descriptor.sql.BasicExtractor: TRACE

　　

 

　运行

 

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C:\Users\l\javademo\microservice-consumer-movie>mvn spring-boot:run
[INFO] Scanning for projects...
[WARNING]
[WARNING] Some problems were encountered while building the effective model for com.shiyanlou:microservice-consumer-movie:jar:1.0-SNAPSHOT
[WARNING] 'dependencies.dependency.(groupId:artifactId:type:classifier)' must be unique: org.springframework.boot:spring-boot-starter-web:jar -> duplicate declaration of version 2.4.
2 @ line 50, column 21
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING]
[INFO]
[INFO] -------------< com.shiyanlou:microservice-consumer-movie >--------------
[INFO] Building microservice-consumer-movie 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] >>> spring-boot-maven-plugin:2.4.2:run (default-cli) > test-compile @ microservice-consumer-movie >>>
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ microservice-consumer-movie ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 1 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ microservice-consumer-movie ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ microservice-consumer-movie ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ microservice-consumer-movie ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] <<< spring-boot-maven-plugin:2.4.2:run (default-cli) < test-compile @ microservice-consumer-movie <<<
[INFO]
[INFO]
[INFO] --- spring-boot-maven-plugin:2.4.2:run (default-cli) @ microservice-consumer-movie ---
[INFO] Attaching agents: []
 
  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.4.2)
 
2021-02-19 11:29:55.620  INFO 5708 --- [           main] com.shiyanlou.App                        : Starting App using Java 1.8.0_111 on DESKTOP-SRVQTV7 with PID 5708 (C:\Users\l\jav
ademo\microservice-consumer-movie\target\classes started by l in C:\Users\l\javademo\microservice-consumer-movie)
2021-02-19 11:29:55.623  INFO 5708 --- [           main] com.shiyanlou.App                        : No active profile set, falling back to default profiles: default
2021-02-19 11:29:56.211  INFO 5708 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2021-02-19 11:29:56.227  INFO 5708 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 7 ms. Found 0 JPA repository interface
s.
2021-02-19 11:29:57.594  INFO 5708 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8010 (http)
2021-02-19 11:29:57.605  INFO 5708 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-02-19 11:29:57.606  INFO 5708 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.41]
2021-02-19 11:29:57.686  INFO 5708 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2021-02-19 11:29:57.686  INFO 5708 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2013 ms
2021-02-19 11:29:57.825  INFO 5708 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2021-02-19 11:29:57.922  INFO 5708 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
2021-02-19 11:29:57.964  INFO 5708 --- [           main] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [name: default]
2021-02-19 11:29:58.011  INFO 5708 --- [           main] org.hibernate.Version                    : HHH000412: Hibernate ORM core version 5.4.27.Final
2021-02-19 11:29:58.134  INFO 5708 --- [           main] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.1.2.Final}
2021-02-19 11:29:58.251  INFO 5708 --- [           main] org.hibernate.dialect.Dialect            : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
2021-02-19 11:29:58.472  INFO 5708 --- [           main] o.h.e.t.j.p.i.JtaPlatformInitiator       : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta
.platform.internal.NoJtaPlatform]
2021-02-19 11:29:58.484  INFO 5708 --- [           main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2021-02-19 11:29:58.712  WARN 5708 --- [           main] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be
performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2021-02-19 11:29:58.812  INFO 5708 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2021-02-19 11:29:59.000  INFO 5708 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8010 (http) with context path ''
2021-02-19 11:29:59.010  INFO 5708 --- [           main] com.shiyanlou.App                        : Started App in 3.838 seconds (JVM running for 4.264)
2021-02-19 11:30:21.980  INFO 5708 --- [nio-8010-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-02-19 11:30:21.981  INFO 5708 --- [nio-8010-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2021-02-19 11:30:21.983  INFO 5708 --- [nio-8010-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 1 ms
2021-02-19 11:31:51.962  INFO 5708 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
2021-02-19 11:31:51.962  INFO 5708 --- [extShutdownHook] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default'
2021-02-19 11:31:51.963  INFO 5708 --- [extShutdownHook] .SchemaDropperImpl$DelayedDropActionImpl : HHH000477: Starting delayed evictData of schema as part of SessionFactory shut-dow
n'
2021-02-19 11:31:52.307  INFO 5708 --- [extShutdownHook] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2021-02-19 11:31:52.313  INFO 5708 --- [extShutdownHook] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  02:01 min
[INFO] Finished at: 2021-02-19T11:31:52+08:00
[INFO] ------------------------------------------------------------------------
终止批处理操作吗(Y/N)? ^Cy
 
C:\Users\l\javademo\microservice-consumer-movie>mvn spring-boot:run
[INFO] Scanning for projects...
[INFO]
[INFO] -------------< com.shiyanlou:microservice-consumer-movie >--------------
[INFO] Building microservice-consumer-movie 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] >>> spring-boot-maven-plugin:2.4.2:run (default-cli) > test-compile @ microservice-consumer-movie >>>
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ microservice-consumer-movie ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 1 resource
[INFO]
[INFO] --- maven-compiler-plugin:2.5.1:compile (default-compile) @ microservice-consumer-movie ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ microservice-consumer-movie ---
[WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:2.5.1:testCompile (default-testCompile) @ microservice-consumer-movie ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] <<< spring-boot-maven-plugin:2.4.2:run (default-cli) < test-compile @ microservice-consumer-movie <<<
[INFO]
[INFO]
[INFO] --- spring-boot-maven-plugin:2.4.2:run (default-cli) @ microservice-consumer-movie ---
[INFO] Attaching agents: []
 
  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.4.2)
 
2021-02-19 11:38:14.507  INFO 13400 --- [           main] com.shiyanlou.App                        : Starting App using Java 1.8.0_111 on DESKTOP-SRVQTV7 with PID 13400 (C:\Users\l\j
avademo\microservice-consumer-movie\target\classes started by l in C:\Users\l\javademo\microservice-consumer-movie)
2021-02-19 11:38:14.510  INFO 13400 --- [           main] com.shiyanlou.App                        : No active profile set, falling back to default profiles: default
2021-02-19 11:38:15.114  INFO 13400 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2021-02-19 11:38:15.128  INFO 13400 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 7 ms. Found 0 JPA repository interfac
es.
2021-02-19 11:38:16.513  INFO 13400 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8010 (http)
2021-02-19 11:38:16.526  INFO 13400 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-02-19 11:38:16.527  INFO 13400 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.41]
2021-02-19 11:38:16.621  INFO 13400 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2021-02-19 11:38:16.622  INFO 13400 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 2063 ms
2021-02-19 11:38:16.768  INFO 13400 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2021-02-19 11:38:16.877  INFO 13400 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
2021-02-19 11:38:16.918  INFO 13400 --- [           main] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [name: default]
2021-02-19 11:38:16.965  INFO 13400 --- [           main] org.hibernate.Version                    : HHH000412: Hibernate ORM core version 5.4.27.Final
2021-02-19 11:38:17.085  INFO 13400 --- [           main] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.1.2.Final}
2021-02-19 11:38:17.203  INFO 13400 --- [           main] org.hibernate.dialect.Dialect            : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
2021-02-19 11:38:17.422  INFO 13400 --- [           main] o.h.e.t.j.p.i.JtaPlatformInitiator       : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jt
a.platform.internal.NoJtaPlatform]
2021-02-19 11:38:17.433  INFO 13400 --- [           main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2021-02-19 11:38:17.505  WARN 13400 --- [           main] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be
 performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2021-02-19 11:38:17.604  INFO 13400 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2021-02-19 11:38:17.788  INFO 13400 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8010 (http) with context path ''
2021-02-19 11:38:17.796  INFO 13400 --- [           main] com.shiyanlou.App                        : Started App in 3.746 seconds (JVM running for 4.252)
2021-02-19 11:38:22.197  INFO 13400 --- [nio-8010-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-02-19 11:38:22.198  INFO 13400 --- [nio-8010-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2021-02-19 11:38:22.200  INFO 13400 --- [nio-8010-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 1 ms

　　

 

 

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\Users\l\javademo\microservice-consumer-movie>curl http://localhost:8010/movies/users/1
{"id":1,"username":"account1","name":"瀵姳绗?,"age":20,"balance":100.00}
C:\Users\l\javademo\microservice-consumer-movie>curl http://localhost:8010/movies/users/1
{"id":1,"username":"account1","name":"瀵姳绗?,"age":20,"balance":100.00}
C:\Users\l\javademo\microservice-consumer-movie>curl http://localhost:8010/movies/users/2
{"id":2,"username":"account2","name":"閺夊骸娲?,"age":28,"balance":180.00}