4.Feign改造项目结构

作者: 溅十三 | 来源:发表于2020-05-17 13:10 被阅读0次

image.png

1.创建公共接口层

使用了@FeignClient("feign-client")注解，那么下游也要用到feign组件
如果怕影响下游，那么直接提供接口即可，不使用@FeignClient注解和 @PostMapping；一般会打两个2包，一个支持springCloud(FeignClient)，另一个直接使用接口
pom:

<?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">
    <parent>
        <artifactId>spring-cloud-demo</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
        <relativePath>../../pom.xml</relativePath>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>feign-client-intf</artifactId>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
    </dependencies>

</project>

IService :

package com.imooc.springcloud;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestParam;

/**
 * Created by 半仙.
 */
@FeignClient("feign-client")
public interface IService {

    @GetMapping("/sayHi")
    public String sayHi();

    @PostMapping("/sayHi")
    public Friend sayHiPost(@RequestBody Friend friend);

    @GetMapping("/retry")
    public String retry(@RequestParam(name = "timeout") int timeout);

    @GetMapping("/error")
    public String error();
}

Friend:

package com.imooc.springcloud;

import lombok.Data;

/**
 * Created by 半仙.
 */
@Data
public class Friend {

    private String name;

    private String port;

}

Product:

package com.imooc.springcloud;

import lombok.Builder;
import lombok.Data;

/**
 * Created by 半仙.
 */
@Data
@Builder
public class Product {

    private Long productId;

    private String description;

    private Long stock;

}

2.创建服务提供者feign-client

pom:
去除了<artifactId>spring-cloud-starter-openfeign</artifactId>的引用？

<?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">
    <parent>
        <artifactId>spring-cloud-demo</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
        <relativePath>../../pom.xml</relativePath>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>feign-client</artifactId>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <dependency>
            <groupId>com.imooc</groupId>
            <artifactId>feign-client-intf</artifactId>
            <version>${project.version}</version>
        </dependency>

    </dependencies>

</project>

FeignClientApplication启动类：
去除了feign的注解？client不需要调用feign接口

package com.imooc.springcloud;

import org.springframework.boot.WebApplicationType;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

/**
 * Created by 半仙.
 */
@EnableDiscoveryClient
@SpringBootApplication
public class FeignClientApplication {

    public static void main(String[] args) {
        new SpringApplicationBuilder(FeignClientApplication.class)
                .web(WebApplicationType.SERVLET)
                .run(args);
    }

}

sonacheck的代码重复率检查？
Controller类：

需要implements IService

package com.imooc.springcloud;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.logging.Log;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

/**
 * Created by 半仙.
 */
@RestController
@Slf4j
public class Controller implements IService {

    @Value("${server.port}")
    private String port;


    @GetMapping("/sayHi2")
    public String sayHi2() {
        return "This is " + port;
    }

    @Override
    public String sayHi() {
        return "This is " + port;
    }

    @Override
    public Friend sayHiPost(@RequestBody Friend friend) {
        log.info("You are " + friend.getName());
        friend.setPort(port);
        return friend;
    }

    @Override
    public String retry(@RequestParam(name = "timeout") int timeout) {
        while (--timeout >= 0) {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
            }
        }
        log.info("retry " + port);
        return port;
    }

    @Override
    public String error() {
        throw new RuntimeException("black sheep");
    }
}

3.创建消费者

如果自己pom引用的包，和下游的冲突了怎么办？使用，tomcat禁用的方式重新引入
pom:

<?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">
    <parent>
        <artifactId>spring-cloud-demo</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
        <relativePath>../../pom.xml</relativePath>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>feign-consumer-advanced</artifactId>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <dependency>
            <groupId>com.imooc</groupId>
            <artifactId>feign-client-intf</artifactId>
            <version>1.0.0-SNAPSHOT</version>
        </dependency>
    </dependencies>

</project>

FeingConsumerApp启动类:
Feign默认的扫包路径？当main方法的扫包路径
接口处层是另外一个公司提供的怎么办？2种方法
1.@EnableFeignClients配置上扫包路径
2.添加注解方式（推荐，更为灵活）

image.png

最新的G版不被允许，会有2个FeignClient上下文，使用配置文件的方式处理
spring.main.allow-bean-definition-overriding=true

package com.imooc.springcloud;

import org.springframework.boot.WebApplicationType;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.cloud.openfeign.FeignClient;

/**
 * Created by 半仙.
 */
@EnableDiscoveryClient
@SpringBootApplication
@EnableFeignClients
public class FeingConsumerApp {

    public static void main(String[] args) {
        new SpringApplicationBuilder(FeingConsumerApp.class)
                .web(WebApplicationType.SERVLET)
                .run(args);
    }

}

Controller类:

package com.imooc.springcloud;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * Created by 半仙.
 */
@RestController
@Slf4j
public class Controller {

    @Autowired
    private IService service;

    @GetMapping("/sayHi")
    public String sayHi() {
        return service.sayHi();
    }

//    @PostMapping("/sayHi")
//    public Friend sayHi2() {
//        Friend friend = new Friend();
//        friend.setName("test");
//        return service.sayHiPost(friend);
//    }
//
//    @GetMapping("/retry")
//    public String retry(Integer timeout) {
//        return service.retry(timeout);
//    }

}

4.Feign改造项目结构

1.创建公共接口层

2.创建服务提供者feign-client

3.创建消费者

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