Spring Cloud学习03--OpenFeign基本使用

OpenFeign功能：Feign是一种声明式、模板化的HTTP客户端。现在已升级为OpenFeign。基本使用方式如下。

1.修改02-customer项目

在pom文件中添加openfeign的引用：

1 <dependencies>
2     <dependency>
3         <groupId>org.springframework.cloud</groupId>
4         <artifactId>spring-cloud-starter-openfeign</artifactId>
5     </dependency>
6 <!--
7     其他组件的引用
8 -->9 </dependencies>

修改02-customer的启动类，添加一个注解：

 1 package com.yangasen;
 2 
 3 import org.springframework.boot.SpringApplication;
 4 import org.springframework.boot.autoconfigure.SpringBootApplication;
 5 import org.springframework.cloud.client.loadbalancer.LoadBalanced;
 6 import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
 7 import org.springframework.cloud.openfeign.EnableFeignClients;
 8 import org.springframework.context.annotation.Bean;
 9 import org.springframework.web.client.RestTemplate;
10 
11 @SpringBootApplication
12 @EnableEurekaClient
13 @EnableFeignClients
14 public class CustomerApplication {
15     public static void main(String[] args) {
16         SpringApplication.run(CustomerApplication.class,args);
17     }
18     @Bean
19     @LoadBalanced
20     public RestTemplate restTemplate(){
21         return new RestTemplate();
22     }
23 }

在02和03项目中添加lombok注解，并定义一个Customer类，：

1 <dependency>
2     <groupId>org.projectlombok</groupId>
3     <artifactId>lombok</artifactId>
4 </dependency>

 1 package com.yangasen.entity;
 2 
 3 import lombok.AllArgsConstructor;
 4 import lombok.Data;
 5 import lombok.NoArgsConstructor;
 6 
 7 @Data
 8 @NoArgsConstructor
 9 @AllArgsConstructor
10 public class Customer {
11 
12     private Integer id;
13 
14     private String name;
15 
16     private Integer age;
17 }

在02-customer中添加一个接口，用于映射03-search项目注册在EUREKA中注册的SEARCH服务：

 1 package com.yangasen.client;
 2 
 3 import com.yangasen.entity.Customer;
 4 import org.springframework.cloud.openfeign.FeignClient;
 5 import org.springframework.web.bind.annotation.*;
 6 
 7 @FeignClient("SEARCH")
 8 public interface SearchClient {
 9     @RequestMapping(method = RequestMethod.GET, value = "/search")
10     String search();
11 
12     //单个参数时，推荐使用@PathVariable
13     @RequestMapping(value = "/search/{id}",method = RequestMethod.GET)
14     Customer findById(@PathVariable(value = "id") Integer id);
15 
16     //多个参数时，也可以采用@RequestParam，不要省略Value属性
17     @RequestMapping(value="/getcustomer",method = RequestMethod.GET)
18     Customer getCustomer(@RequestParam(value = "id") Integer id, @RequestParam(value = "name") String Name);
19 
20     //传递的参数比较复杂时，会采用POST的方式请求，传递对象时统一采用JSON格式发送，需要添加@RequestBody注解
21     @RequestMapping(value = "/save",method = RequestMethod.GET)//自动转换为post请求 405
22     Customer save(@RequestBody Customer customer);
23 }

其中第10、14、18、22行对应的是03-search中controller的action：

 1 package com.yangasen.controller;
 2 
 3 import com.yangasen.entity.Customer;
 4 import org.springframework.beans.factory.annotation.Value;
 5 import org.springframework.web.bind.annotation.*;
 6 
 7 @RestController
 8 public class SearchController {
 9 
10     @Value("${server.port}")
11     private String port;
12 
13     @GetMapping("/search")
14     public String search(){
15         return "search:"+port;
16     }
17 
18 
19     @GetMapping("/search/{id}")
20     public Customer findById(@PathVariable Integer id){
21         return new Customer(1,"zhangsan",18);
22     }
23 
24     @GetMapping("/getcustomer")
25     public Customer getCustomer(@RequestParam Integer id,@RequestParam String name){
26         return new Customer(id,name,18);
27     }
28 
29     @PostMapping("/save")//自动转换为post请求 405
30     public  Customer save(@RequestBody Customer customer){
31         return customer;
32     }
33 }

最后修改02-customer的controller，修改调用方式，通过spring获取接口的实例，直接调用实例的search()方法：

 1 package com.yangasen.controller;
 2 
 3 import com.netflix.discovery.EurekaClient;
 4 import com.yangasen.client.SearchClient;
 5 import com.yangasen.entity.Customer;
 6 import org.springframework.beans.factory.annotation.Autowired;
 7 import org.springframework.web.bind.annotation.GetMapping;
 8 import org.springframework.web.bind.annotation.PathVariable;
 9 import org.springframework.web.bind.annotation.RequestParam;
10 import org.springframework.web.bind.annotation.RestController;
11 import org.springframework.web.client.RestTemplate;
12 
13 @RestController
14 public class CustomerController {
15 
16     @Autowired
17     private RestTemplate restTemplate;
18 
19     @Autowired
20     private EurekaClient eurekaClient;
21 
22     @Autowired
23     private SearchClient searchClient;
24 
25     @GetMapping("/customer")
26     public String customer(){
27         String result = searchClient.search();
28         return result;
29     }
30 
31     @GetMapping("/search/{id}")
32     public Customer findById(@PathVariable Integer id){
33         return searchClient.findById(id);
34     }
35 
36     @GetMapping("/getcustomer")
37     public Customer findById(@RequestParam Integer id, @RequestParam String name){
38         return searchClient.getCustomer(id,name);
39     }
40 
41     @GetMapping("/save")//自动转换为post请求
42     public  Customer save(Customer customer){
43         return searchClient.save(customer);
44     }
45 }

2.测试效果：

重启全部五个模块，可以得到与之前一样的效果。

访问：http://localhost:8080/customer

可轮询(权重)得到8081和8082的服务的响应。

访问：http://localhost:8080/search/1

访问：http://locahost:8080/getcustomer?id=1&name=xxx

访问：http://localhost:8080/save?id=1&name=xxx&age=10

posted on 2020-12-14 08:31 Sempron2800+ 阅读(114) 评论(0) 编辑收藏举报