第七章 SpringCloud之非声明式RestClient:Feign

study-url:https://cloud.spring.io/spring-cloud-static/spring-cloud-netflix/1.4.6.RELEASE/multi/multi_spring-cloud-feign.html#netflix-feign-starter

####################使用默认的Feign方式###########################

1、pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.test</groupId>
    <artifactId>eureka-client-feign</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>eureka-client-feign</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2、添加application.yml

spring:
  application:
    name: eureka-client-feign  #应用名
logging:  #logging日志配置
  level:
    root: INFO
    org.hibernate: INFO
server:
  port: 8666   #服务端口

eureka:
  instance:
    hostname: localhost
    prefer-ip-address: true
    instance-id: ${spring.application.name}:${spring.application.instance_id:${server.port}}
  client:
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:8661/eureka

3、启动类添加注解

package com.test.eurekaclientfeign;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication
@EnableFeignClients
public class EurekaClientFeignApplication {
    public static void main(String[] args) {
        SpringApplication.run(EurekaClientFeignApplication.class, args);
    }

}

4、创建UserFeignClient.java,这个类配置Feign远程调用的URL

package com.test.eurekaclientfeign.feign;

import com.test.eurekaclientfeign.entity.User;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@FeignClient("eureka-client-user") //指明feign远程调用的虚拟主机名
public interface UserFeignClient {
    //远程服务自己设置的urn,目前feign只支持RequestMapping注解
    @RequestMapping(method = RequestMethod.GET, value = "/user/{id}")
     User findById(@PathVariable("id") Long id);
}

5、创建MovieController.java，这里是本机提供服务的类，也是调用远程服务的调用方。

package com.test.eurekaclientfeign.controller;


import com.test.eurekaclientfeign.entity.User;
import com.test.eurekaclientfeign.feign.UserFeignClient;
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;

@RestController
public class MovieController {

    @Autowired
    private UserFeignClient userFeignClient;
/*
    @Autowired
    private FeignClient1 feignClient1;*/

    @GetMapping(value = "/movie/{id}")
    public User findById(@PathVariable("id") Long id) {
        return this.userFeignClient.findById(id);
    }

    /*@GetMapping(value = "/{serviceName}")
    public String findServiceInfoFromEurekaByServiceName(@PathVariable("serviceName") String serviceName) {
        System.out.println("11111111");
        return this.feignClient1.findServiceInfoFromEurekaByServiceName(serviceName);
    }*/

}

6、创建User.java

package com.test.eurekaclientfeign.entity;

import java.io.Serializable;
import java.math.BigDecimal;


public class User implements Serializable {

    private  Long id;

    private  String name;

    private  String username;

    private  BigDecimal balance;

    private  short age;

    public Long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public BigDecimal getBalance() {
        return balance;
    }

    public void setBalance(BigDecimal balance) {
        this.balance = balance;
    }

    public short getAge() {
        return age;
    }

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

7、访问URL

http://localhost:8661/   #服务发现
http://192.168.137.1:8666/movie/1   #Feign测试接口

至此，已实现Feign的基本调用。

######################使用自己配置Feign方式#########################

注意：在上面的基础上，将上面的方式注释，然后再采用下面的方式

1、创建自己配置的UserFeignClientConfig.java Feign类

package com.test.eurekaclientfeign.feign;

import feign.Contract;
import feign.Logger;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class UserFeignClientConfig {
  /*  @Bean
    public Contract feignContract() {
        return new feign.Contract.Default();
    }*/

    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.FULL;
    }
}

2、创建一个UserFeignClient1.java ，将自己创建的Feign 配置类通过@FeignClient(name = "eureka-client-user", configuration = UserFeignClientConfig.class)添加进去。

package com.test.eurekaclientfeign.feign;

import com.test.eurekaclientfeign.entity.User;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@FeignClient(name = "eureka-client-user", configuration = UserFeignClientConfig.class)
public interface UserFeignClient1 {
    @RequestMapping(method = RequestMethod.GET, value = "/user/{id}")
    User findById(@PathVariable("id") Long id);
}

3、控制类

package com.test.eurekaclientfeign.controller;

import com.test.eurekaclientfeign.entity.User;
import com.test.eurekaclientfeign.feign.UserFeignClient1;
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;

@RestController
public class MovieController {

   /* @Autowired
    private UserFeignClient userFeignClient;*/

    @Autowired(required = true)
    private UserFeignClient1 userFeignClient1;

    @GetMapping(value = "/config/{id}")
    public User findById(@PathVariable("id") Long id) {
        return this.userFeignClient1.findById(id);
    }

    /*@GetMapping(value = "/{serviceName}")
    public String findServiceInfoFromEurekaByServiceName(@PathVariable("serviceName") String serviceName) {
        System.out.println("11111111");
        return this.feignClient1.findServiceInfoFromEurekaByServiceName(serviceName);
    }*/

}