Feign是一個聲明式的Web服務客戶端。這使得Web服務客戶端的寫入更加方便 要使用Feign創建一個界面並對其進行註釋。它具有可插入註釋支持,包括Feign註釋和JAX-RS註釋。Feign還支持可插拔編碼器和解碼器。Spring Cloud增加了對Spring MVC註釋的支持,並使用Spring Web中默認使用的HttpMessageConverters。Spring Cloud集成Ribbon和Eureka以在使用Feign時提供負載均衡的http客戶端。
Spring Cloud 調用的兩種方式:res + Ribbon和Feign。
新建一個Feign客戶端:
IJ IDEA File->New->Project->Spring ->initializr,
取名SericeFeign,Finish.
目錄結構和Spring Boot的目錄結構一樣。
pom文件如下:
<?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.heyaunjun.serice-feign</groupId>
<artifactId>serice-feign</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>serice-feign</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.8.RELEASE</version>
<relativePath/>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Camden.SR7</spring-cloud.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>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Camden.SR7</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>
</repository>
<repository>
<id>repository.springframework.maven.snapshot</id>
<name>Spring Framework Maven Snapshot Repository</name>
<url>http://repo.spring.io/snapshot/</url>
</repository>
</repositories>
</project>
注意:
依賴管理的版本不能使用Dalston.SR4,如果使用了這個版本,啓動的時候會報一個日誌類加載不了的錯誤,具體原因不詳。使用Camden.SR7這個版本啓動正常。
新建一個service包,包內新建一個接口,SayHiService,接口加上註解@FeignClient(value = “service-hi”),service-hi是服務名稱
/**
* @author heyuanjun
*/
@FeignClient(value = "service-hi")
public interface SayHiService {
/**
* hello SpringCloud
* @param name 用戶名
* @return
*/
@RequestMapping(value = "/hi",method = RequestMethod.GET)
String sayHi(@RequestParam(value = "name") String name);
}
新建一個controller包,包內新建一個SayHiController:
/**
* @author heyaunjun
*/
@Controller
public class SayHiController {
@Autowired
SayHiService serviceSayHi;
@RequestMapping(value = "/hi",method = RequestMethod.GET)
@ResponseBody
public String sayHi(@RequestParam String name){
return serviceSayHi.sayHi(name);
}
}
啓動類上加上註解@EnableDiscoveryClient,@EnableFeignClients
/**
* @author heyuanjun
*/
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class SericeFeignApplication {
public static void main(String[] args) {
SpringApplication.run(SericeFeignApplication.class, args);
}
}
application.yml(默認的是application.property,將其修改成application.yml)文件作如下配置:
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8761/eureka/
server:
port: 8765
spring:
application:
name:
同樣注意值前面的佔位符。
啓動以前新建好的服務註冊中心,兩個服務,啓動剛剛新建好的serice-feign
瀏覽器訪問localhost:8761
可以看到兩個服務和Feign客戶端已經註冊到了註冊中心。
瀏覽器訪問http://localhost:8765/hi?name=下班
多次訪問,端口號交替是8762和8763,說明客戶端遠程調用服務成功。
各種IT書籍書目及下載鏈接
https://blog.csdn.net/dh1027/article/details/89327978