springCloud入门

作者: IT小池 | 来源:发表于2020-03-02 19:11 被阅读0次

创建父工程spring-cloud，引入依赖

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <packaging>pom</packaging>
    <modules>
        <module>cloud-eureka-server</module>
        <module>cloud-service-provider</module>
        <module>cloud-service-consumer</module>
    </modules>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.cloud</groupId>
    <artifactId>spring-cloud</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-cloud</name>
    <description>spring-cloud project for Spring Boot</description>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <!--SpringCloud 版本-->
        <!-- spring-cloud Finchley.SR1 版本 ==> springBoot 2.0.4 没有报错
            <spring-cloud.version>Finchley.SR1</spring-cloud.version>
            spring-cloud Hoxton.SR1 Hoxton.SR2 版本 ==> springBoot 2.2.4 没有报错
            <spring-cloud.version>Hoxton.SR1</spring-cloud.version>
        -->
        <spring-cloud.version>Finchley.SR1</spring-cloud.version>
    </properties>

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

Eureka 注册中心

创建子工程Eureka 注册中心（cloud-eureka-server），引入 Eureka

<?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">
    <parent>
        <artifactId>spring-cloud</artifactId>
        <groupId>com.cloud</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-eureka-server</artifactId>

    <dependencies>
        <!-- Eureka 服务端 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
    </dependencies>
</project>

创建注册中心启动类，Application.java

package com.cloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

/**
 *  Eureka 注册中心
 */
@SpringBootApplication
@EnableEurekaServer
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }
}

在配置文件中配置application.yml,

spring:
  application:
    name: eureka-server
server:
  port: 10086
eureka:
  client:
    # 本身就是 Eureka 注册中心，不需要获取与注册，只需要提供
    # 是否注册到Eureka，如果是单机版不需要注册到其他Eureka
    register-with-eureka: false
    # 表示是否从Eureka Server获取注册信息，默认为true
    fetch-registry: false
    service-url:
      # 对外提供服务的url
      defaultZone: http://127.0.0.1:${server.port}/eureka
  instance:
    prefer-ip-address: true
    ip-address: 127.0.0.1

服务提供者

创建子工程 服务提供者（cloud-service-provider），引入依赖

<?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">
    <parent>
        <artifactId>spring-cloud</artifactId>
        <groupId>com.cloud</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-service-provider</artifactId>

    <dependencies>
        <!-- Eureka 客户端 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <!-- 由于 Eureka-client 没有Tomcat的依赖，所以Spring容器无法创建一些实例，从而导致项目无法启动 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
</project>

创建服务提供者启动类Application，注意：@EnableEurekaClient 只能注册到 Eureka，而@EnableDiscoveryClient 兼容 Eureka zookeeper，所以使用 @EnableDiscoveryClient

package com.cloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

// @EnableEurekaClient 只能注册到 Eureka,
@EnableDiscoveryClient // 兼容 Eureka zookeeper
@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }
}

配置文件 application.yml ,

spring:
  application:
    name: eureka-provider
server:
  port: 8761
eureka:
  client:
    service-url:
      # 链接服务注册中心，将服务注册到注册中心
      defaultZone: http://127.0.0.1:10086/eureka

创建与一个接口 TestController,

package com.cloud.service;

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

import java.util.HashMap;
import java.util.Map;

@RestController
@RequestMapping("/provider")
public class TestController {

    @RequestMapping("/test")
    public Map test(){
        Map map = new HashMap();
        map.put("name","小二");
        return map;
    }
}

服务消费者

创建子工程服务消费者（cloud-service-consumer），引入依赖

<?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">
    <parent>
        <artifactId>spring-cloud</artifactId>
        <groupId>com.cloud</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-service-consumer</artifactId>

    <dependencies>
        <!-- Eureka 客户端 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <!-- 由于 Eureka-client 没有Tomcat的依赖，所以Spring容器无法创建一些实例，从而导致项目无法启动 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- openfeign 远程调用服务 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
    </dependencies>
</project>

创建服务消费者启动类 Application.java，注意：@EnableEurekaClient 只能注册到 Eureka，而@EnableDiscoveryClient 兼容 Eureka zookeeper，所以使用 @EnableDiscoveryClient，这里由于需要使用 httpClient远程调用来，所以配置spring提供的 RestTemplate

package com.cloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;

@EnableFeignClients
// @EnableEurekaClient 只能注册到 Eureka,
@EnableDiscoveryClient // 兼容 Eureka zookeeper
@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }

    @Bean
    public RestTemplate restTemplate(ClientHttpRequestFactory factory){
        return new RestTemplate(factory);
    }

    @Bean
    public ClientHttpRequestFactory simpleClientHttpRequestFactory(){
        SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
        factory.setReadTimeout(180000);//单位为ms
        factory.setConnectTimeout(5000);//单位为ms
        return factory;
    }
}

配置文件 application.yml,

spring:
  application:
    name: eureka-consumer
server:
  port: 8088
eureka:
  client:
    service-url:
      # 连接服务中心，将服务注册到注册中心
      defaultZone: http://127.0.0.1:10086/eureka

在创建一个测试控制器 TestController,

package com.cloud.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import java.util.List;
import java.util.Map;

@RestController
@RequestMapping("/consumer")
public class TestController {

    @Autowired
    private RestTemplate restTemplate;
    @Autowired
    private DiscoveryClient discoveryClient;

    @RequestMapping("/test")
    public Map test(){
        # 从注册中心获取服务提供者
        List<ServiceInstance> instances = discoveryClient.getInstances("eureka-provider");
        ServiceInstance instance = instances.get(0);
        String host = instance.getHost();
        int port = instance.getPort();
        String url = "http://" + host + ":" + port + "/provider/test";
        # 调用服务提供者接口
        Map result = restTemplate.getForObject(url, Map.class);
        return result;
    }

    // ===================== feign 远程调用 ======================
    @Autowired
    private TestClient testClient;

    @RequestMapping("/test/feign")
    public Map testFeign(){
        return testClient.test();
    }
}

然后依次启动 注册中心、服务提供者、服务消费者，然后浏览器访问 http://localhost:8088/consumer/test](http://localhost:8088/consumer/test 将返回服务提供者中定义的数据 {"name":"小二"}。当前包下创建client.TestClient.java

package com.cloud.client;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;

import java.util.Map;

@FeignClient(name = "eureka-provider")
public interface TestClient {

    @GetMapping("/provider/test")
    Map test();
}

springCloud入门

Eureka 注册中心

服务提供者

服务消费者

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