Feign的入门案例实战

比眉伴天荒 2021-07-24 19:56 378阅读 0赞

**一 pom文件**

<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>ch4-1</artifactId>
            <groupId>cn.springcloud.book</groupId>
            <version>1.0-SNAPSHOT</version>
        </parent>
        <modelVersion>4.0.0</modelVersion>
    
    
        <artifactId>ch4-1-hello</artifactId>
        <packaging>jar</packaging>
    
    
        <name>ch4-1-hello</name>
        <url>http://springcloud.cn</url>
    
    
        <properties>
            <spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
        </properties>
    
    
        <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>
    
    
        <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>
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    
    
        <repositories>
            <repository>
                <id>spring-snapshots</id>
                <name>Spring Snapshots</name>
                <url>https://repo.spring.io/snapshot</url>
                <snapshots>
                    <enabled>true</enabled>
                </snapshots>
            </repository>
            <repository>
                <id>spring-milestones</id>
                <name>Spring Milestones</name>
                <url>https://repo.spring.io/milestone</url>
                <snapshots>
                    <enabled>false</enabled>
                </snapshots>
            </repository>
        </repositories>
    
    
        <pluginRepositories>
            <pluginRepository>
                <id>spring-snapshots</id>
                <name>Spring Snapshots</name>
                <url>https://repo.spring.io/snapshot</url>
                <snapshots>
                    <enabled>true</enabled>
                </snapshots>
            </pluginRepository>
            <pluginRepository>
                <id>spring-milestones</id>
                <name>Spring Milestones</name>
                <url>https://repo.spring.io/milestone</url>
                <snapshots>
                    <enabled>false</enabled>
                </snapshots>
            </pluginRepository>
        </pluginRepositories>
    
    
    
    
    </project>

**二 入口程序**

package cn.springcloud.book.feign;
    
    
    
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.openfeign.EnableFeignClients;
    
    
    @SpringBootApplication
    @EnableFeignClients
    public class SpringCloudFeignApplication {
    
    
       public static void main(String[] args) {
          SpringApplication.run(SpringCloudFeignApplication.class, args);
       }
    }

**三 编写Feign的接口**

package cn.springcloud.book.feign.service;
    
    
    import cn.springcloud.book.feign.config.HelloFeignServiceConfig;
    import org.springframework.cloud.openfeign.FeignClient;
    import org.springframework.http.ResponseEntity;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.RequestParam;
    
    
    @FeignClient(name = "github-client", url = "https://api.github.com", configuration = HelloFeignServiceConfig.class)
    public interface HelloFeignService {
    
    
        /**
         * content: {"message":"Validation Failed","errors":[{"resource":"Search","field":"q","code":"missing"}],
         * "documentation_url":"https://developer.github.com/v3/search"}
         * @param queryStr
         * @return
         */
        @RequestMapping(value = "/search/repositories", method = RequestMethod.GET)
        String searchRepo(@RequestParam("q") String queryStr);
    
    
    }

**四 编写控制器并依赖注入Feign**

package cn.springcloud.book.feign.controller;
    
    
    import cn.springcloud.book.feign.service.HelloFeignService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.http.ResponseEntity;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    
    @RestController
    public class HelloFeignController {
    
    
        @Autowired
        private HelloFeignService helloFeignService;
    
    
        // 服务消费者对位提供的服务
        @GetMapping(value = "/search/github")
        public String searchGithubRepoByStr(@RequestParam("str") String queryStr) {
            return helloFeignService.searchRepo(queryStr);
        }
    }

**五 编写配置类**

package cn.springcloud.book.feign.config;
    
    
    import feign.Logger;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    
    @Configuration
    public class HelloFeignServiceConfig {
    
    
        /**
         *
         * Logger.Level 的具体级别如下：
             NONE：不记录任何信息
             BASIC：仅记录请求方法、URL以及响应状态码和执行时间
             HEADERS：除了记录 BASIC级别的信息外，还会记录请求和响应的头信息
             FULL：记录所有请求与响应的明细，包括头信息、请求体、元数据
         * @return
         */
        @Bean
        Logger.Level feignLoggerLevel() {
            return Logger.Level.FULL;
        }
    
    
    }

**六 运行结果**

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