Spring Cloud在一个服务中使用Feign远程调用另一个服务

超、凢脫俗 2022-03-10 16:00 364阅读 0赞

首先是搭建服务注册中心Eureka Server

参考：

[https://blog.csdn.net/weixin\_42465125/article/details/88233722][https_blog.csdn.net_weixin_42465125_article_details_88233722]

[https://blog.csdn.net/weixin\_42465125/article/details/88337698][https_blog.csdn.net_weixin_42465125_article_details_88337698]

两个客户端工程结构如下：

![20190311154942951.png][]

采用的是Maven的聚合工程，聚合工程的创建参考：[https://blog.csdn.net/weixin\_42465125/article/details/87906095][https_blog.csdn.net_weixin_42465125_article_details_87906095]

cuit-product-center和cuit-user-center作为父工程，cuit-product-center-\*和cuit-user-center-\*为聚合的子模块

### cuit-product-center父工程： ###

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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    	<modelVersion>4.0.0</modelVersion>
    	<groupId>cn.cuit.product</groupId>
    	<artifactId>cuit-product-center</artifactId>
    	<version>1.0.0</version>
    	<packaging>pom</packaging>
    
    	<modules>
    		<module>cuit-product-center-api</module>
    		<module>cuit-product-center-service</module>
    	</modules>
    
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.1.3.RELEASE</version>
    		<relativePath /> 
    	</parent>
    
    	<properties>
    		<java.version>1.8</java.version>
    		<spring-cloud.version>Greenwich.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>
    
    	
    	
    
    	<repositories>
    		<repository>
    			<id>spring-milestones</id>
    			<name>Spring Milestones</name>
    			<url>https://repo.spring.io/milestone</url>
    		</repository>
    	</repositories>
    </project>

### cuit-product-center-api子模块： ###

该模块下面放的是domain类和service接口

pom文件：

Product类:

package cn.cuit.product.center.api.domian;
    
    import java.io.Serializable;
    
    public class Product implements Serializable {
    
    	private static final long serialVersionUID = 3895325943679327522L;
    
    	private String id;
    
    	private String name;
    
    	private Integer price;
    
    	public Product() {
    	}
    
    	public Product(String name, Integer price) {
    		this.name = name;
    		this.price = price;
    	}
    
    	public Product(String id, String name, Integer price) {
    		this.id = id;
    		this.name = name;
    		this.price = price;
    	}
    
    	public String getId() {
    		return id;
    	}
    
    	public void setId(String id) {
    		this.id = id;
    	}
    
    	public String getName() {
    		return name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    	public Integer getPrice() {
    		return price;
    	}
    
    	public void setPrice(Integer price) {
    		this.price = price;
    	}
    }

ProductService接口：

package cn.cuit.product.center.api.service;
    
    import cn.cuit.product.center.api.domian.Product;
    
    public interface ProductService {
    
    	Product getProductById(String id);
    
    }

### cuit-product-center-service子模块： ###

该模块主要放Controller类和Service实现及Feign接口和启动类

pom文件：

<?xml version="1.0"?>
    <project
    	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
    	xmlns="http://maven.apache.org/POM/4.0.0"
    	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    	<modelVersion>4.0.0</modelVersion>
    
    	<parent>
    		<groupId>cn.cuit.product</groupId>
    		<artifactId>cuit-product-center</artifactId>
    		<version>1.0.0</version>
    	</parent>
    
    	<artifactId>cuit-product-center-service</artifactId>
    	<name>cuit-product-center-service</name>
    	<url>http://maven.apache.org</url>
    
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>cn.cuit.product</groupId>
    			<artifactId>cuit-product-center-api</artifactId>
    			<version>1.0.0</version>
    		</dependency>
    
    		<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-feign</artifactId>
    			<version>1.4.6.RELEASE</version>
    		</dependency>
    	</dependencies>
    </project>

properties配置文件：

spring.aop.auto = true
    spring.aop.proxy-target-class = true
    
    # logback日志配置,日志环境类型，服务名，级别
    log.env.profile = dev
    log.env.module = cuit-product-center-service
    log.env.logger.level = info
    
    #服务提供者的名字
    spring.application.name = cuit-product-center-service
    
    #服务提供者的端口号
    server.port=8088
    
    #服务上下文配置，springboot2.X
    server.servlet.context-path=/cuit-product-center-service
    
    #服务注册中心的地址
    
    #无需验证的方式： 
    #eureka.client.serviceUrl.defaultZone=http://localhost:8761/eureka/
    #有用户名密码的验证方式，Eureka服务端依赖SpringSecurity
    eureka.client.serviceUrl.defaultZone=http://user:pwd@localhost:8761/eureka/

日志文件：

<?xml version="1.0" encoding="UTF-8"?>
    <configuration>
        <include resource="org/springframework/boot/logging/logback/base.xml"/>
        <property resource="application.properties"/>
    
        <appender name="ROLLING" class="ch.qos.logback.core.rolling.RollingFileAppender">
            <file>logs/${log.env.module}.log</file>
            <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
                <fileNamePattern>logs/${log.env.module}-%d{yyyy-MM-dd}.%i.log
                </fileNamePattern>
                <maxFileSize>5MB</maxFileSize>
                <maxHistory>30</maxHistory>
                <totalSizeCap>20GB</totalSizeCap>
            </rollingPolicy>
            <encoder>
                <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level [%.15thread] %logger{36}:%X{sysUser} - %.-4096msg%n</pattern>
                <charset>UTF-8</charset>
            </encoder>
        </appender>
    
        <root level="${log.env.logger.level}">
            <appender-ref ref="ROLLING"/>
        </root>
    </configuration>

启动类：

package cn.cuit.product.center.service;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    import org.springframework.cloud.openfeign.EnableFeignClients;
    
    @SpringBootApplication
    // 将自己作为一个可以被Eureka Server发现注册的Client
    @EnableDiscoveryClient
    // 将自己作为一个可以被其他服务通过Feign调用的Client
    @EnableFeignClients
    public class App {
    	public static void main(String[] args) {
    		SpringApplication.run(App.class, args);
    	}
    }

Controller：

package cn.cuit.product.center.service.controller;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    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.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    import cn.cuit.product.center.api.domian.Product;
    import cn.cuit.product.center.api.service.ProductService;
    
    @RestController
    @RequestMapping("/api/products")
    public class ProductController {
    
    	private final Logger logger = LoggerFactory.getLogger(this.getClass());
    
    	@Autowired
    	private ProductService productService;
    
    	// 远程访问的经验，先保证自己访问能访问通，再去整另外一个服务来调这个服务，否则坑是填不完的
    
    	// http://localhost:8088/cuit-product-center-service/api/products/testFeign?a=10&b=20
    	@GetMapping("/testFeign")
    	public String testFeign(@RequestParam Integer a, @RequestParam Integer b) {
    		logger.info(">>>>>>>>>>>>>>>>通过Feign远程调用成功 a = {}, b = {}", a, b);
    		return "通过Feign远程调用成功 a + b = " + (a + b);
    	}
    
    	// http://localhost:8088/cuit-product-center-service/api/products/getProductById/10
    	@GetMapping("/getProductById/{id}")
    	public Product getProductById(@PathVariable("id") String id) {
    		logger.info(">>>>>>>>>>>>>>>>通过Feign远程调用成功 ");
    		return productService.getProductById(id);
    	}
    }

Service实现：

package cn.cuit.product.center.service.impl;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.stereotype.Service;
    
    import cn.cuit.product.center.api.domian.Product;
    import cn.cuit.product.center.api.service.ProductService;
    
    @Service
    public class ProductServiceImpl implements ProductService {
    
    	private static final Logger LOG = LoggerFactory.getLogger(ProductServiceImpl.class);
    
    	@Override
    	public Product getProductById(String id) {
    		LOG.info(">>>>>>>>>>>>>id = {}", id);
    		return new Product(id, "cuit", 998);
    	}
    
    }

测试本地调用是否好使：

访问：

[http://localhost:8088/cuit-product-center-service/api/products/testFeign?a=10&b=20][http_localhost_8088_cuit-product-center-service_api_products_testFeign_a_10_b_20]

![20190311160000195.png][]

[http://localhost:8088/cuit-product-center-service/api/products/getProductById/10][http_localhost_8088_cuit-product-center-service_api_products_getProductById_10]

![20190311160008719.png][]

然后搭建另一个user服务：大体与上面一致

主要实现：

Controller：

package cn.cuit.user.center.service.controller;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    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.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    import cn.cuit.product.center.api.domian.Product;
    import cn.cuit.user.center.service.feign.UserCenterProductFeign;
    
    @RestController
    @RequestMapping("/api/users")
    public class UserController {
    
    	private final Logger LOG = LoggerFactory.getLogger(this.getClass());
    
    	@Autowired
    	private UserCenterProductFeign userCenterProductFeign;
    
    	// http://localhost:8081/cuit-user-center-service/api/users/testFeign?a=10&b=20
    	@GetMapping(value = "/testFeign")
    	public String testCallUserServiceWithFeign(@RequestParam Integer a, @RequestParam Integer b) {
    		LOG.info("in cuit-user-center-service a = {}, b = {}", a, b);
    		String msg = userCenterProductFeign.sum(a, b);
    		return msg;
    	}
    
    	// http://localhost:8081/cuit-user-center-service/api/products/getProductById/10
    	@GetMapping(value = "/getProductById/{id}")
    	public Product getProductById(@PathVariable("id") String id) {
    		LOG.info(".................in cuit-user-center-service id = {}", id);
    		Product product = userCenterProductFeign.getProductById(id);
    		return product;
    	}
    }

UserCenterProductFeign：

package cn.cuit.user.center.service.feign;
    
    import org.springframework.cloud.openfeign.FeignClient;
    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.RequestMethod;
    import org.springframework.web.bind.annotation.RequestParam;
    
    import cn.cuit.product.center.api.domian.Product;
    
    /**
     * Feign Client
     */
    // @FeignClient注解配置 要调用的那个服务
    // 如果配置错误会报：
    /**
     * java.lang.RuntimeException: com.netflix.client.ClientException: Load balancer
     * does not have available server for client: XXX-Service
     */
    @FeignClient("cuit-product-center-service")
    public interface UserCenterProductFeign {
    
    	// 远程服务请求的url,
    	// 注意这里的神坑，虽然不是问题，但是真的很坑，就是不要忘了Controller类上面的@RequestMapping路径和properties里面的context-path路径
    	// 如果没配对本服务报500，Feign报404【404表示找不到资源，一般大多数是请求路径不对，或者参数没对】，
    	// SynchronousMethodHandler#executeAndDecode#97行发起调用，到LoadBalancerFeignClient类的57行，就可以看到请求的url
    	@RequestMapping(value = "/product-service/api/products/testFeign", method = RequestMethod.GET)
    	public String sum(@RequestParam Integer a, @RequestParam Integer b);
    
    	// 旧版Feign不能使用@GetMapping会报错
    	@GetMapping("/product-service/api/products/getProductById/{id}")
    	public Product getProductById(@PathVariable("id") String id);
    }

发起远程调用：

访问：

[http://localhost:8081/cuit-user-center-service/api/users/testFeign?a=10&b=20][http_localhost_8081_cuit-user-center-service_api_users_testFeign_a_10_b_20]

![20190311160240898.png][]

[http://localhost:8081/cuit-user-center-service/api/users/getProductById/23][http_localhost_8081_cuit-user-center-service_api_users_getProductById_23]

![20190311160251285.png][]

完整代码GitHub地址： [https://github.com/CUITLLB/eureka-feign-remote-call-demo][https_github.com_CUITLLB_eureka-feign-remote-call-demo]

\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* 不积跬步无以至千里，不积小流无以成江海 \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*

[https_blog.csdn.net_weixin_42465125_article_details_88233722]: https://blog.csdn.net/weixin_42465125/article/details/88233722
[https_blog.csdn.net_weixin_42465125_article_details_88337698]: https://blog.csdn.net/weixin_42465125/article/details/88337698
[20190311154942951.png]: /images/20220310/022e0c1449a64f7fb9ff12f29cf7c520.png
[https_blog.csdn.net_weixin_42465125_article_details_87906095]: https://blog.csdn.net/weixin_42465125/article/details/87906095
[http_localhost_8088_cuit-product-center-service_api_products_testFeign_a_10_b_20]: http://localhost:8088/cuit-product-center-service/api/products/testFeign?a=10&b=20
[20190311160000195.png]: /images/20220310/171c61f8a59644c88bd86832c8255248.png
[http_localhost_8088_cuit-product-center-service_api_products_getProductById_10]: http://localhost:8088/cuit-product-center-service/api/products/getProductById/10
[20190311160008719.png]: /images/20220310/06d3f55d85984d768134b339058c4816.png
[http_localhost_8081_cuit-user-center-service_api_users_testFeign_a_10_b_20]: http://localhost:8081/cuit-user-center-service/api/users/testFeign?a=10&b=20
[20190311160240898.png]: /images/20220310/97fa04b2fbea46e0abe506f02e3209b4.png
[http_localhost_8081_cuit-user-center-service_api_users_getProductById_23]: http://localhost:8081/cuit-user-center-service/api/users/getProductById/23
[20190311160251285.png]: /images/20220310/08474914c2ba4f4c96e444de7dac8a40.png
[https_github.com_CUITLLB_eureka-feign-remote-call-demo]: https://github.com/CUITLLB/eureka-feign-remote-call-demo