SpringCloud-OpenFeign(三）

悠悠 2023-10-13 23:56 27阅读 0赞

**目录**

简介

Feign与OpenFeign

方式 一（工作中不怎么使用）

创建OpenFeign服务

pom文件

配置文件

AClient接口

OpenFeignDemoController

启动类

结果

方式二（工作中常用）

创建OpenFeign服务

pom文件

配置文件

APlushClient接口

OpenFeignDemoController

启动类

api服务

Hello接口

Eureka-App-a服务

pom文件

配置文件

HelloController

启动类

结果

--------------------

## 简介 ##

在上篇中我们通过restTemplate跨进程调用接口，但是在实际工作中我们并不使用它来跨进程调用。在服务eureka-app-b中通过

String ret = restTemplate.getForObject("http://a/echo?name=123", String.class);

调用，显然代码并不优雅，由此更优雅的跨进程调用方式就出现了。

## Feign与OpenFeign ##

Feign是一个开源声明式WebService客户端，用于简化服务通信；Feign采用"接口+注解"方式开发，屏蔽了网络通信的细节；

OpenFeign是SpringCloud对Feign的增强，支持SpringMVC注解；

## 方式 一（工作中不怎么使用） ##

### 创建OpenFeign服务 ###

![4d1f33457cae4e1d9fc57138818f994a.png][]

#### pom文件 ####

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>com.chensir</groupId>
            <artifactId>spring-cloud-root</artifactId>
            <version>0.0.1-SNAPSHOT</version>
            <relativePath>../pom.xml</relativePath>
        </parent>
    
        <artifactId>spring-cloud-openfeign-demo</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-netflix-eureka-client</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-openfeign</artifactId>
            </dependency>
            <dependency>
                <groupId>cn.hutool</groupId>
                <artifactId>hutool-all</artifactId>
    
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <optional>true</optional>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
         
    
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <configuration>
                        <excludes>
                            <exclude>
                                <groupId>org.projectlombok</groupId>
                                <artifactId>lombok</artifactId>
                            </exclude>
                        </excludes>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    
    </project>

#### 配置文件 ####

server.port = 9092
    spring.application.name = opfei
    eureka.client.fetch-registry=true
    eureka.instance.ip-address = 172.17.204.119
    eureka.instance.instance-id = ${eureka.instance.ip-address}:${server.port}
    eureka.instance.hostname =  ${eureka.instance.ip-address}
    
    eureka.client.service-url.defaultZone=http://ek1.cn:8001/eureka/,http://ek2.cn:8002/eureka/

#### AClient接口 ####

//此注解类似 @service、@mapper 调用a服务
    @FeignClient("a")
    public interface AClient {
    
        @GetMapping("/echo")
        String  hello(@RequestParam String  name);
    
    
    }

#### OpenFeignDemoController ####

@RestController
    public class OpenFeignDemoController {
    
        @Autowired
        private AClient aClient;
    
    
        @GetMapping("/test")
        public  String  test() {
            String ret = aClient.hello("辣目洋子");
    
            return ret;
        }
    }

**此示例调用的仍是a服务中/echo接口**

#### 启动类 ####

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

#### 结果 ####

![d459ddc0ac38416da1123a4079b24b21.png][]

## 方式二（工作中常用） ##

> **在工作中api服务就是事先定义好的各个接口，a服务就是api接口的实现类（b服务、c服务均可去实现api中定义的接口）。而此OpenFeignDemo就是调用方，去调用api服务中的接口 并且在调用时可以指定调用哪个实现类服务。**

### 创建OpenFeign服务 ###

![398d29678fe144b9bbe86c3c1cdb4a12.png][]

![183267aa5ba741b6957c1583ccfc53fc.png][]

#### pom文件 ####

比上方示例多个api包

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>com.chensir</groupId>
            <artifactId>spring-cloud-root</artifactId>
            <version>0.0.1-SNAPSHOT</version>
            <relativePath>../pom.xml</relativePath>
        </parent>
    
        <artifactId>spring-cloud-openfeign-demo</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-netflix-eureka-client</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-openfeign</artifactId>
            </dependency>
            <dependency>
                <groupId>cn.hutool</groupId>
                <artifactId>hutool-all</artifactId>
    
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <optional>true</optional>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>com.chensir</groupId>
                <artifactId>spring-cloud-api</artifactId>
                <version>0.0.1-SNAPSHOT</version>
                <scope>compile</scope>
            </dependency>
        </dependencies>
    
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <configuration>
                        <excludes>
                            <exclude>
                                <groupId>org.projectlombok</groupId>
                                <artifactId>lombok</artifactId>
                            </exclude>
                        </excludes>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    
    </project>

#### 配置文件 ####

内容没变

#### APlushClient接口 ####

@FeignClient("a")
    public interface APlusClient extends Hello {
    }

#### OpenFeignDemoController ####

@RestController
    public class OpenFeignDemoController {
    
        @Autowired
        private APlusClient aPlusClient;
    
        @GetMapping("/test")
        public  String  test() {
            String ret = aPlusClient.userJDdou(100);
    
            return ret;
        }
    }

#### 启动类 ####

### api服务 ###

#### Hello接口 ####

public interface Hello {
    
        @GetMapping("/hello")
        String  hello();
    
    
        @GetMapping("/jingdou/{userId}")
        String  userJDdou(@PathVariable Integer userId);
    
    }

**就这些，没其他的。**

### **Eureka-App-a服务** ###

#### **pom文件** ####

**就多个api包**

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>com.chensir</groupId>
            <artifactId>spring-cloud-root</artifactId>
            <version>0.0.1-SNAPSHOT</version>
            <relativePath>../pom.xml</relativePath>
        </parent>
    
        <artifactId>eureka-app-a</artifactId>
    
        <name>eureka-app-a</name>
        <description>eureka-app-a</description>
    
        <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-client</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
    
            <dependency>
                <groupId>cn.hutool</groupId>
                <artifactId>hutool-all</artifactId>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <optional>true</optional>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>com.chensir</groupId>
                <artifactId>spring-cloud-api</artifactId>
                <version>0.0.1-SNAPSHOT</version>
                <scope>compile</scope>
            </dependency>
        </dependencies>
    
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <configuration>
                        <excludes>
                            <exclude>
                                <groupId>org.projectlombok</groupId>
                                <artifactId>lombok</artifactId>
                            </exclude>
                        </excludes>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    
    </project>

#### 配置文件 ####

没变

#### HelloController ####

@RestController
    public class HelloController implements Hello {
        @Override
        public String hello() {
            return "这是通过外部接口定义的Controller实现方法";
        }
    
        @Override
        public String userJDdou(Integer userId) {
            return StrUtil.format("用户{}有250个京豆",userId) ;
        }
    }

#### 启动类 ####

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

### 结果 ###

![dc668b95b53a42b5b20ff2bb4988308b.png][]

[4d1f33457cae4e1d9fc57138818f994a.png]: https://img-blog.csdnimg.cn/4d1f33457cae4e1d9fc57138818f994a.png
[d459ddc0ac38416da1123a4079b24b21.png]: https://img-blog.csdnimg.cn/d459ddc0ac38416da1123a4079b24b21.png
[398d29678fe144b9bbe86c3c1cdb4a12.png]: https://img-blog.csdnimg.cn/398d29678fe144b9bbe86c3c1cdb4a12.png
[183267aa5ba741b6957c1583ccfc53fc.png]: https://img-blog.csdnimg.cn/183267aa5ba741b6957c1583ccfc53fc.png
[dc668b95b53a42b5b20ff2bb4988308b.png]: https://img-blog.csdnimg.cn/dc668b95b53a42b5b20ff2bb4988308b.png