Feign是一个声明式的Web服务客户端。这使得Web服务客户端的写入更加方便 要使用Feign创建一个界面并对其进行注释。它具有可插入注释支持,包括Feign注释和JAX-RS注释。Feign还支持可插拔编码器和解码器。Spring Cloud增加了对Spring MVC注释的支持,并使用Spring Web中默认使用的HttpMessageConverters。Spring Cloud集成Ribbon和Eureka以在使用Feign时提供负载均衡的http客户端。
Spring Cloud 调用的两种方式:res + Ribbon和Feign。
新建一个Feign客户端:
IJ IDEA File->New->Project->Spring ->initializr,
取名SericeFeign,Finish.
目录结构和Spring Boot的目录结构一样。
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:
依赖管理的版本不能使用Dalston.SR4,如果使用了这个版本,启动的时候会报一个日志类加载不了的错误,具体原因不详。使用Camden.SR7这个版本启动正常。
新建一个service包,包内新建一个接口,SayHiService,接口加上注解@FeignClient(value = “service-hi”),service-hi是服务名称
/**
* @author heyuanjun
*/
@FeignClient(value = "service-hi")
public interface SayHiService {
/**
* hello SpringCloud
* @param name 用户名
* @return
*/
@RequestMapping(value = "/hi",method = RequestMethod.GET)
String sayHi(@RequestParam(value = "name") String name);
}
新建一个controller包,包内新建一个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);
}
}
启动类上加上注解@EnableDiscoveryClient,@EnableFeignClients
/**
* @author heyuanjun
*/
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class SericeFeignApplication {
public static void main(String[] args) {
SpringApplication.run(SericeFeignApplication.class, args);
}
}
application.yml(默认的是application.property,将其修改成application.yml)文件作如下配置:
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8761/eureka/
server:
port: 8765
spring:
application:
name:
同样注意值前面的占位符。
启动以前新建好的服务注册中心,两个服务,启动刚刚新建好的serice-feign
浏览器访问localhost:8761
可以看到两个服务和Feign客户端已经注册到了注册中心。
浏览器访问http://localhost:8765/hi?name=下班
多次访问,端口号交替是8762和8763,说明客户端远程调用服务成功。
各种IT书籍书目及下载链接
https://blog.csdn.net/dh1027/article/details/89327978