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springcloud是什麼?
Spring Cloud爲開發人員提供了快速構建分佈式系統中一些常見模式的工具(例如配置管理,服務發現,斷路器,智能路由,控制總微代理,線,一次性令牌,全局鎖定,領導選舉,分佈式會話,集羣狀態)。分佈式系統的協調導致鍋爐板模式,使用Spring Cloud開發人員可以快速站起來實現這些模式的服務和應用程序。它們適用於任何分佈式環境,包括開發人員自己的筆記本電腦,裸機數據中心和Cloud Foundry等託管平臺。
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什麼分佈式系統?
分佈式就是將一個系統拆分成很多的子系統,比如淘寶系統,他有許許多多的子系統:會員系統、訂單系統、積分系統等等,這樣已拆分就大大的減輕了服務器的壓力,如果想深入瞭解分佈式的架構,還請百度分佈式架構,這裏不多做說明。
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什麼是Feign
既然一個系統被拆分成了無數個子系統,那系統之間是如何進行通信的呢?假如我現在在訂單系統中想獲取到會員的信息,此時,你能怎麼做?
可能你會說用外鏈接查詢,這個也沒啥錯,但是正規的分佈式系統都是將對應的表分給了對應的庫,所以這裏鏈接查詢是走不通的,這時,你可能在想,要是我能直接調用會員服務的方法那該多好,Feign就來了,他解決了服務與服務之間的通訊。
Feign是一種聲明式、模板化的HTTP客戶端。在Spring Cloud中使用Feign, 我們可以做到使用HTTP請求遠程服務時能與調用本地方法一樣的編碼體驗,開發者完全感知不到這是遠程方法,更感知不到這是個HTTP請求,類似於Dubbo的RPC。
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eureka
如果想實現服務與服務之前的調用,那麼必須要有eureka這個註冊中心,eureka在這裏不多做解釋,直接看代碼:
1.創建一個eureka-service的springboot項目。
2.maven依賴:
<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.ymy</groupId>
<artifactId>sprintcloud</artifactId>
<version>0.0.1-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<!--eureka server -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka-server</artifactId>
</dependency>
<!-- spring boot test -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Dalston.RC1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
</project>
不需要的jar可以不引用。
3.添加配置文件:
server:
port: 8769
eureka:
instance:
hostname: localhost
client:
registerWithEureka: false
fetchRegistry: false
serviceUrl:
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
這樣eureka服務算是大功告成。
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服務端1(被調用端1)
創建一個springboot項目:
pom文件:
<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.ymy.client1</groupId>
<artifactId>cloud-client1</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>boot1</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Dalston.RC1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
</project>
新建配置文件:application.yml
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8769/eureka/
server:
port: 8762
spring:
application:
name: service-hi
啓動類:我將controller直接寫在了啓動類了,你們可以新建一個controller包
package com.ymy;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
@EnableEurekaClient
@SpringBootApplication
@RestController
@RequestMapping("c")
public class App1 {
public static void main(String[] args) {
SpringApplication.run(App1.class, args);
}
@Value("${server.port}")
String port;
@GetMapping("hello")
public String hello(@RequestParam String name){
return "hello "+name+" 我的服務端口是:"+port;
}
}
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服務端2(被調用端2)
新建一個springboot項目:
pom文件:
<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.ymy.client1</groupId>
<artifactId>cloud-client1</artifactId>
<version>0.0.1-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Dalston.RC1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
</project>
新建配置文件:application.yml
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8769/eureka/
server:
port: 8763
spring:
application:
name: service-hi
啓動類:
package com.ymy;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
@EnableEurekaClient
@SpringBootApplication
@RestController
@RequestMapping("c")
public class App2 {
public static void main(String[] args) {
SpringApplication.run(App2.class, args);
}
@Value("${server.port}")
String port;
@GetMapping("hello")
public String hello(@RequestParam String name){
return "hello "+name+" 我的服務端口是:"+port;
}
}
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客服端(調用端)
新建一個springboot項目
pom配置文件:
<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.ymy.client3</groupId>
<artifactId>cloud-client3</artifactId>
<version>0.0.1-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-feign</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!-- 斷路器 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-hystrix</artifactId>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Dalston.RC1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
</project>
新建application.yml文件
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8769/eureka/
server:
port: 8765
spring:
application:
name: service-feign
feign:
hystrix:
enabled: true
controller類:
package com.ymy.controller;
import javax.inject.Inject;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import com.ymy.feign.ClientFeign;
import com.ymy.feign.HystrixClientFeign;
@RestController
public class MyController {
@Inject
private ClientFeign clientFeign;
// @Autowired
// private HystrixClientFeign hystrixClientFeign;
@GetMapping("hi")
public String hi(@RequestParam String name){
return clientFeign.getHello(name);
}
/*@GetMapping("hihi")
public String hihi(@RequestParam String name){
System.out.println("哈哈哈哈");
return hystrixClientFeign.hello(name);
}*/
}
重點來了,Feign的運用:
ClientFeign類:
package com.ymy.feign;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
@FeignClient(value = "service-hi", fallback = HystrixClientFeign.class)
public interface ClientFeign {
@GetMapping("c/hello")
String getHello(@RequestParam(value = "name") String name);
}
HystrixClientFeign類:
package com.ymy.feign;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
@Component
public class HystrixClientFeign implements ClientFeign{
// @Autowired
// private RestTemplate restTemplate;
// @HystrixCommand(defaultFallback="hiError")
// public String hello(String name){
// return restTemplate.getForObject("http://service-hi/hello?name="+name, String.class);
// }
/*public String hiError(String name) {
return "hi," + name + ",sorry,error!";
}*/
@Override
public String getHello(String name) {
return "hello " + name + ", error!";
}
}
代碼已經貼的差不多了,下面我們來看運行結果:
兩個服務端我做的是集羣,客服端以輪詢的方式訪問,有興趣的小夥伴可以試試哦,需要源碼的可以留言哦。