一 什么是Feign
Feign使我们写Java的HTTP客户端更加容易，我们常说的Feign其实更多的是与SpringCloud结合的Spring Cloud OpenFeign。这里的快速上手，也是结合SpringCloud的示例。
二 写一个provider服务
用SpringBoot快速写一个provider服务，并暴露rest接口，如下：
项目可以到 https://start.spring.io/ 快速生成。
写ProviderController如下：
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| package com.qicoder.feign.provider.controller;
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;
@RestController
@RequestMapping("/provider")
public class ProviderController {
@GetMapping("test1")
public String test1() {
return "测试";
}
@GetMapping("test2")
public String test2(@RequestParam String name) {
return "hello," + name;
}
}
|
application.yaml如下
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| server:
port: 8081
spring:
application:
name: provider-server
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三 写一个Consumer服务
需要额外引入依赖：
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| <dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
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需要@EnableFeignClients注解,如果定义的FeignClien在FeignConsumerApplication类所在包或者子包下，则不需要额外指定包路径。
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| package com.qicoder.feign.consumer;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.openfeign.EnableFeignClients;
@EnableFeignClients
@SpringBootApplication
public class FeignConsumerApplication {
public static void main(String[] args) {
SpringApplication.run(FeignConsumerApplication.class, args);
}
}
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写FeignClient如下(由于我们这里演示未使用eureka等注册中心，故需要指定url)：
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| package com.qicoder.feign.consumer.feign;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
@FeignClient(contextId = "ProviderService", name = "provider-server", url = "http://localhost:8081")
@RequestMapping("/provider")
public interface ProviderService {
@GetMapping("test1")
String test1();
@GetMapping("test2")
String test2(@RequestParam String name);
}
|
写ConsumerController如下：
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| package com.qicoder.feign.consumer.controller;
import com.qicoder.feign.consumer.feign.ProviderService;
import org.springframework.beans.factory.annotation.Autowired;
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;
@RestController
@RequestMapping("/consumer")
public class ConsumerController {
@Autowired
private ProviderService providerService;
@GetMapping("test1")
public String test1() {
return "provider的返回：" + providerService.test1();
}
@GetMapping("test2")
public String test2(@RequestParam String name) {
return "provider的返回：" + providerService.test2(name);
}
}
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四 结果
provider两个链接：
http://localhost:8081/provider/test1
返回:
http://localhost:8081/provider/test2?name=zhangsan
返回:
consumer两个链接：
http://localhost:8082/consumer/test1
返回：
http://localhost:8082/consumer/test2?name=zhangsan
返回：
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| provider的返回：hello,zhangsan
|
