SpringCloud学习 - Feign声明式服务调用客户端//接口方式

1. Feign声明式服务调用客户端//接口方式

书签：

1、小小例子

2、Get多个请求参数处理

 

1. 小小例子

新建项目：eureka-consumer-feign

pom核心配置：

org.springframework.cloud    spring-cloud-starter-openfeign

 

创建接口：FeignTest.java

package cn.ywj.eurekaconsumerfeign; 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.RequestMethod; @FeignClient("eureka-provider")// 指定要访问的服务提供者 public interface FeignTest {     @RequestMapping(method = RequestMethod.GET, value = "/t")// 服务提供的请求地址     public String t(); }

 

项目启动类：EurekaConsumerFeignApplication.java, 核心注解：@EnableFeignClients

package cn.ywj.eurekaconsumerfeign; import com.netflix.loadbalancer.IRule; import com.netflix.loadbalancer.RandomRule; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.openfeign.EnableFeignClients; import org.springframework.context.annotation.Bean; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @SpringBootApplication @RestController @EnableFeignClients public class EurekaConsumerFeignApplication {    @Autowired    private FeignTest feignTest;    @RequestMapping("/t")    public String t(){       return feignTest.t();    }    public static void main(String[] args) {       SpringApplication.run(EurekaConsumerFeignApplication.class, args);    } }

 

运行项目访问，一样可以得到结果。Feign集成了Ribbon,也可以注入IRule使用各种负载均衡功能。

1. Get多个请求参数处理

单参数请求参数时，没什么问题，多参数时，有会问题，，，

当FeignTest接口中添加新的方法

@RequestMapping(method = RequestMethod.GET, value = "/t2") public User t2(User user);

 

然后Controller请求

@RequestMapping("/t2") public String t2(User user){    User user1 = feignTest.t2(user);    return user1 == null ? "null" : user1.getName()+":"+user1.getAge(); }

 

http://127.0.0.1:8083/t2?name=ywj&age=17 

此时会报错：

content:{"timestamp":"2018-10-10T09:14:43.547+0000","status":405,"error":"Method Not Allowed","message":"Request method 'POST' not supported","path":"/t2"}

 

处理方法：

• 第一种：把user参数拆分成name,age

FeignTest.java @RequestMapping(method = RequestMethod.GET, value = "/t3") public User t3(@RequestParam("name") String name, @RequestParam("age") Integer age);   eureka-provider @GetMapping("/t3") public User t3(@RequestParam("name") String name, @RequestParam("age") Integer age){    User user = new User();    user.setName(name);    user.setAge(age);    return user; }

 

• 第二种：换成Post请求

FeignTest.java @RequestMapping(method = RequestMethod.POST, value = "/t5") public User t5(User user);   eureka-provider @PostMapping("/t5") public User t5(@RequestBody User user){    return user; }