Spring cloud 学习（二）Feign

Feign:一个可以把远程服务提供方的 rest 接口变成本地方法调用
 
对上一个项目进行改造：
 
1.改造service0



 
Service0.java:
 
package service0;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

@SpringBootApplication(scanBasePackages = "service0")
@EnableEurekaClient
@EnableWebMvc
public class Service0 {
   
    public static void main(String[] args) {
        SpringApplication.run(Service0.class, args);
    }
}

-----------------------------------------------------------------------------------------------------------
Service0Controller.java:
package service0.controller;
import java.util.Date;
import org.apache.commons.lang.time.FastDateFormat;
import org.springframework.web.bind.annotation.*;

@RestController
public class Service0Controller {
   
    @GetMapping("/service0/{value}")
    public String service0(@PathVariable("value") String value){
        return value + ":" + FastDateFormat.getInstance("yyyy-MM-dd HH:mm:ss.sss").format(new Date());
    }
   
}

------------------------------------------------------------------------------
启动discovery，启动service0后，测试service0的调用：



 
2.改造service1



 
Service1.java:
package service1;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
@SpringBootApplication(scanBasePackages = "service1")
@EnableFeignClients
@EnableDiscoveryClient
@EnableWebMvc
public class Service1 {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        SpringApplication.run(Service1.class, args);
    }
}

 
--------------------------------------------------------------------
Server0Client.java:
 
package service1.client;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@FeignClient("service0") //service0的application中的name属性一致
public interface Server0Client {
   
    @RequestMapping(method=RequestMethod.GET,path="/service0/{value}")
    public String service0(@PathVariable("value") String value);//与service0controller的方法一致
}

 
 
--------------------------------------------------------------------------
Service1Controller.java:
package service1.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import service1.client.Server0Client;
@RestController
public class Service1Controller {
   
    @Autowired
    private Server0Client server0Client;
   
    @GetMapping("/service1/{value2}")
    public String service1(@PathVariable("value2") String value2){
        return server0Client.service0(value2);
    }
}
-----------------------------------------------------------------------
启动discovery，启动service0，service1后，测试service1的调用：



 
访问service1时，又通过本地调用调用service0的接口，最后返回service0的处理结果。