Feign

Feign是简化Java HTTP客户端开发的工具，是通过处理注解生成Request，从而实现简化Http API开发的目的，即开发人员可以使用注解的方式定制Request api模板，在发送请求http requst之前，feign通过处理注解的方式替换掉request模板中的参数，这种实现方式更为直接，可理解。

Feign是一种声明式，模板化的HTTP客户端，可以做到使用HTTP请求远程服务时能与调用本地方法一样的编码体验，感知不到是远程方法和HTTP请求.

1，服务提供者microservice-provider-user：

package com.taikang.it.mobile.jpa;


import com.taikang.it.mobile.bean.Girl;
import org.springframework.data.jpa.repository.JpaRepository;

import java.util.List;

public interface GirlRepository extends JpaRepository<Girl, Integer> {

    List<Girl> findByAge(Integer age);

}

package com.taikang.it.mobile.controller;

import com.taikang.it.mobile.bean.Girl;
import com.taikang.it.mobile.jpa.GirlRepository;
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.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping(value = "/provider-user")
public class GirlController {

    @Autowired
    private GirlRepository repository;

    @GetMapping(value = "/girls/{id}")
    public Girl queryOne(@PathVariable("id") Integer id) {
        return repository.findOne(id);
    }


}

package com.taikang.it.mobile.bean;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;


@Entity
public class Girl {

    @Id
    @GeneratedValue
    private Integer id;
    private String cupSize;
    private Integer age;
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getCupSize() {
        return cupSize;
    }

    public void setCupSize(String cupSize) {
        this.cupSize = cupSize;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

feign项目

microservice-consumer-movie-feign：

package com.taikang.it.mobile.feign;

import com.taikang.it.mobile.bean.Girl;
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(name = "microservice-provider-user")
public interface GirlFeignClient {

    @RequestMapping(value = "/provider-user/girls/{id}", method = RequestMethod.GET)
    Girl findById(@PathVariable("id") Integer id);

}

package com.taikang.it.mobile.controller;

import com.taikang.it.mobile.bean.Girl;
import com.taikang.it.mobile.feign.GirlFeignClient;
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.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping(value = "provider-feign")
public class MovieController {
    @Autowired
    private GirlFeignClient feignClient;

    @GetMapping("/girls/{id}")
    public Girl findById(@PathVariable Integer id) {
        System.out.println(id);
        return this.feignClient.findById(id);
    }
}

启动eureka，启动2个user实例，启动feign，多次访问http://localhost:8010/provider-feign/girls/4

发现两个user实例都会打印sql日志