feat(master): OpenFeign相关的学习

OpenFeign 的基本认知和使用

dev-protocol-springcloud/dev-protocol-springcloud-communication/pom.xml

@@ -20,6 +20,12 @@
     </properties>
 
     <dependencies>
+        <!-- ribbon -->
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
+        </dependency>
+        <!-- openfeign -->
         <dependency>
             <groupId>io.github.openfeign</groupId>
             <artifactId>feign-micrometer</artifactId>
@@ -28,6 +34,19 @@
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-openfeign</artifactId>
         </dependency>
+        <!-- feign 替换 JDK 默认的 URLConnection 为 okhttp -->
+        <dependency>
+            <groupId>io.github.openfeign</groupId>
+            <artifactId>feign-okhttp</artifactId>
+        </dependency>
+        <!-- 使用原生的 Feign Api 做的自定义配置, encoder 和 decoder -->
+        <dependency>
+            <groupId>io.github.openfeign</groupId>
+            <artifactId>feign-gson</artifactId>
+            <version>12.1</version>
+        </dependency>
+
+        <!-- springboot -->
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
@@ -36,6 +55,8 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
         </dependency>
+
+        <!-- tools -->
         <dependency>
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>

dev-protocol-springcloud/dev-protocol-springcloud-communication/src/main/java/org/example/controller/CommunicationController.java

@@ -2,7 +2,10 @@ package org.example.controller;
 
 import org.example.common.vo.JwtToken;
 import org.example.common.vo.UsernameAndPassword;
+import org.example.feign.UseFeignApi;
+import org.example.service.AuthorityFeignClient;
 import org.example.service.UseRestTemplateService;
+import org.example.service.UseRibbonService;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -16,19 +19,19 @@ import org.springframework.web.bind.annotation.RestController;
 public class CommunicationController {
 
     private final UseRestTemplateService restTemplateService;
-//    private final UseRibbonService ribbonService;
+    private final UseRibbonService ribbonService;
-//    private final AuthorityFeignClient feignClient;
+    private final AuthorityFeignClient feignClient;
-//    private final UseFeignApi useFeignApi;
+    private final UseFeignApi useFeignApi;
 
-    public CommunicationController(UseRestTemplateService restTemplateService
+    public CommunicationController(UseRestTemplateService restTemplateService,
-//                                   UseRibbonService ribbonService,
+                                   UseRibbonService ribbonService,
-//                                   AuthorityFeignClient feignClient,
+                                   AuthorityFeignClient feignClient,
-//                                   UseFeignApi useFeignApi
+                                   UseFeignApi useFeignApi
     ) {
         this.restTemplateService = restTemplateService;
-//        this.ribbonService = ribbonService;
+        this.ribbonService = ribbonService;
-//        this.feignClient = feignClient;
+        this.feignClient = feignClient;
-//        this.useFeignApi = useFeignApi;
+        this.useFeignApi = useFeignApi;
     }
 
     @PostMapping("/rest-template")
@@ -44,7 +47,7 @@ public class CommunicationController {
                 usernameAndPassword);
     }
 
-   /* @PostMapping("/ribbon")
+   @PostMapping("/ribbon")
     public JwtToken getTokenFromAuthorityServiceByRibbon(
             @RequestBody UsernameAndPassword usernameAndPassword) {
         return ribbonService.getTokenFromAuthorityServiceByRibbon(usernameAndPassword);
@@ -63,5 +66,5 @@ public class CommunicationController {
     @PostMapping("/thinking-in-feign")
     public JwtToken thinkingInFeign(@RequestBody UsernameAndPassword usernameAndPassword) {
         return useFeignApi.thinkingInFeign(usernameAndPassword);
-    }*/
+    }
 }

dev-protocol-springcloud/dev-protocol-springcloud-communication/src/main/java/org/example/feign/FeignConfig.java

@@ -0,0 +1,57 @@
+package org.example.feign;
+
+import feign.Logger;
+import feign.Request;
+import feign.Retryer;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import java.util.concurrent.TimeUnit;
+import static java.util.concurrent.TimeUnit.SECONDS;
+
+/**
+ * <h1>OpenFeign 配置类</h1>
+ * */
+@Configuration
+public class FeignConfig {
+
+    /**
+     * <h2>开启 OpenFeign 日志</h2>
+     * */
+    @Bean
+    public Logger.Level feignLogger() {
+        return Logger.Level.FULL;   //  需要注意, 日志级别需要修改成 debug, 因为 feign 基本都是 debug 级别的日志, info 的日志很少
+    }
+
+    /**
+     * <h2>OpenFeign 开启重试</h2>
+     * period = 100 发起当前请求的时间间隔, 单位是 ms
+     * maxPeriod = 1000 发起当前请求的最大时间间隔, 单位是 ms
+     * maxAttempts = 5 最多请求次数
+     * */
+    @Bean
+    public Retryer feignRetryer() {
+        return new Retryer.Default(
+                100,
+                SECONDS.toMillis(1),
+                5
+        );
+    }
+
+    public static final int CONNECT_TIMEOUT_MILLS = 5000;
+    public static final int READ_TIMEOUT_MILLS = 5000;
+
+    /**
+     * <h2>对请求的连接和响应时间进行限制</h2>
+     * */
+    @Bean
+    public Request.Options options() {
+
+        return new Request.Options(
+                CONNECT_TIMEOUT_MILLS, TimeUnit.MICROSECONDS,
+                READ_TIMEOUT_MILLS, TimeUnit.MILLISECONDS,
+                // 转发请求是否要进行限制
+                true
+        );
+    }
+}

dev-protocol-springcloud/dev-protocol-springcloud-communication/src/main/java/org/example/feign/FeignOkHttpConfig.java

@@ -0,0 +1,39 @@
+package org.example.feign;
+
+import feign.Feign;
+import okhttp3.ConnectionPool;
+import okhttp3.OkHttpClient;
+import org.springframework.boot.autoconfigure.AutoConfigureBefore;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.cloud.openfeign.FeignAutoConfiguration;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import java.util.concurrent.TimeUnit;
+
+/**
+ * <h1>OpenFeign 使用 OkHttp 配置类</h1>
+ * 前置条件是 Feign
+ * */
+@Configuration
+@ConditionalOnClass(Feign.class)
+@AutoConfigureBefore(FeignAutoConfiguration.class)
+public class FeignOkHttpConfig {
+
+    /**
+     * <h2>注入 OkHttp, 并自定义配置</h2>
+     * */
+    @Bean
+    public okhttp3.OkHttpClient okHttpClient() {
+
+        return new OkHttpClient.Builder()
+                .connectTimeout(5, TimeUnit.SECONDS)    // 设置连接超时
+                .readTimeout(5, TimeUnit.SECONDS)   // 设置读超时
+                .writeTimeout(5, TimeUnit.SECONDS)  // 设置写超时
+                .retryOnConnectionFailure(true)     // 是否自动重连
+                // 配置连接池中的最大空闲线程个数为 10, 并保持 5 分钟
+                .connectionPool(new ConnectionPool(
+                        10, 5L, TimeUnit.MINUTES))
+                .build();
+    }
+}

dev-protocol-springcloud/dev-protocol-springcloud-communication/src/main/java/org/example/feign/UseFeignApi.java

@@ -0,0 +1,87 @@
+package org.example.feign;
+
+import feign.Feign;
+import feign.Logger;
+import feign.gson.GsonDecoder;
+import feign.gson.GsonEncoder;
+import lombok.extern.slf4j.Slf4j;
+import org.example.common.vo.JwtToken;
+import org.example.common.vo.UsernameAndPassword;
+import org.example.service.AuthorityFeignClient;
+import org.springframework.cloud.client.ServiceInstance;
+import org.springframework.cloud.client.discovery.DiscoveryClient;
+import org.springframework.cloud.openfeign.FeignClient;
+import org.springframework.cloud.openfeign.support.SpringMvcContract;
+import org.springframework.stereotype.Service;
+import org.springframework.util.CollectionUtils;
+
+import java.util.List;
+import java.lang.annotation.Annotation;
+import java.util.Random;
+
+/**
+ * <h1>使用 Feign 的原生 Api, 而不是 OpenFeign = Feign + Ribbon</h1>
+ * */
+@Slf4j
+@Service
+public class UseFeignApi {
+
+    private final DiscoveryClient discoveryClient;
+
+    public UseFeignApi(DiscoveryClient discoveryClient) {
+        this.discoveryClient = discoveryClient;
+    }
+
+    /**
+     * <h2>使用 Feign 原生 api 调用远端服务</h2>
+     * Feign 默认配置初始化、设置自定义配置、生成代理对象
+     * */
+    public JwtToken thinkingInFeign(UsernameAndPassword usernameAndPassword) {
+
+        // 通过反射去拿 serviceId
+        String serviceId = null;
+        Annotation[] annotations = AuthorityFeignClient.class.getAnnotations();
+        for (Annotation annotation : annotations) {
+            if (annotation.annotationType().equals(FeignClient.class)) {
+                serviceId = ((FeignClient) annotation).value();
+                log.info("get service id from AuthorityFeignClient: [{}]", serviceId);
+                break;
+            }
+        }
+
+        // 如果服务 id 不存在, 直接抛异常
+        if (null == serviceId) {
+            throw new RuntimeException("can not get serviceId");
+        }
+
+        // 通过 serviceId 去拿可用服务实例 OpenFeign 是使用 Ribbon 做这个事
+        List<ServiceInstance> targetInstances = discoveryClient.getInstances(serviceId);
+        if (CollectionUtils.isEmpty(targetInstances)) {
+            throw new RuntimeException("can not get target instance from serviceId: " +
+                    serviceId);
+        }
+
+        // 随机选择一个服务实例: 负载均衡
+        ServiceInstance randomInstance = targetInstances.get(
+                new Random().nextInt(targetInstances.size())
+        );
+        log.info("choose service instance: [{}], [{}], [{}]", serviceId,
+                randomInstance.getHost(), randomInstance.getPort());
+
+        // Feign 客户端初始化, 必须要配置 encoder、decoder、contract
+        // 默认的 encoder、decoder 不支持对象,不能实现编解码, 所以要自己进行定义
+        // 默认的 contract 默认的协议不支持 SpringCloud 对应的 Feign 接口
+        AuthorityFeignClient feignClient = Feign.builder()  // 1. Feign 默认配置初始化
+                .encoder(new GsonEncoder())                 // 2.1 设置自定义配置
+                .decoder(new GsonDecoder())                 // 2.2 设置自定义配置
+                .logLevel(Logger.Level.FULL)                // 2.3 设置自定义配置
+                .contract(new SpringMvcContract())
+                .target(                                    // 3 生成代理对象
+                        AuthorityFeignClient.class,
+                        String.format("http://%s:%s",
+                                randomInstance.getHost(), randomInstance.getPort())
+                );
+
+        return feignClient.getTokenByFeign(usernameAndPassword);
+    }
+}

dev-protocol-springcloud/dev-protocol-springcloud-communication/src/main/java/org/example/ribbon/RibbonConfig.java

@@ -0,0 +1,22 @@
+package org.example.ribbon;
+
+import org.springframework.cloud.client.loadbalancer.LoadBalanced;
+import org.springframework.context.annotation.Bean;
+import org.springframework.stereotype.Component;
+import org.springframework.web.client.RestTemplate;
+
+/**
+ * <h1>使用 Ribbon 之前的配置, 增强 RestTemplate</h1>
+ * */
+@Component
+public class RibbonConfig {
+
+    /**
+     * <h2>注入 RestTemplate</h2>
+     * */
+    @Bean
+    @LoadBalanced
+    public RestTemplate restTemplate() {
+        return new RestTemplate();
+    }
+}

dev-protocol-springcloud/dev-protocol-springcloud-communication/src/main/java/org/example/service/AuthorityFeignClient.java

@@ -0,0 +1,31 @@
+package org.example.service;
+
+import org.example.common.vo.JwtToken;
+import org.example.common.vo.UsernameAndPassword;
+import org.springframework.cloud.openfeign.FeignClient;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+
+/**
+ * <h1>与 Authority 服务通信的 Feign Client 接口定义</h1>
+ * */
+@FeignClient(
+        // contextId 是对 FeignClient 的声明, 每一个进行的通信都要进行定义, value 表示需要进行通信的服务id是什么
+        contextId = "AuthorityFeignClient", value = "e-commerce-authority-center"
+//        fallback = AuthorityFeignClientFallback.class
+//        fallbackFactory = AuthorityFeignClientFallbackFactory.class
+)
+public interface AuthorityFeignClient {
+
+    /**
+     * <h2>通过 OpenFeign 访问 Authority 获取 Token</h2>
+     *
+     * value 只需要定义路径即可, 不需要定义 ip + port
+     * consumes, produces: 标识请求和返回的数据格式, 可以不指定, 但是在使用原生 Api 接口的时候必须要进行指定, 要不会不能进行识别对应的接口
+     * */
+    @RequestMapping(value = "/ecommerce-authority-center/authority/token",
+            method = RequestMethod.POST,
+            consumes = "application/json", produces = "application/json")
+    JwtToken getTokenByFeign(@RequestBody UsernameAndPassword usernameAndPassword);
+}

dev-protocol-springcloud/dev-protocol-springcloud-communication/src/main/java/org/example/service/UseRibbonService.java

@@ -0,0 +1,116 @@
+package org.example.service;
+
+import com.alibaba.fastjson.JSON;
+import com.netflix.loadbalancer.*;
+import com.netflix.loadbalancer.reactive.LoadBalancerCommand;
+import lombok.extern.slf4j.Slf4j;
+import org.example.common.constant.CommonConstant;
+import org.example.common.vo.JwtToken;
+import org.example.common.vo.UsernameAndPassword;
+import org.springframework.cloud.client.ServiceInstance;
+import org.springframework.cloud.client.discovery.DiscoveryClient;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+import org.springframework.stereotype.Service;
+import org.springframework.web.client.RestTemplate;
+import rx.Observable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * <h1>使用 Ribbon 实现微服务通信</h1>
+ * */
+@Slf4j
+@Service
+public class UseRibbonService {
+
+    private final RestTemplate restTemplate;
+    private final DiscoveryClient discoveryClient;
+
+    public UseRibbonService(RestTemplate restTemplate,
+                            DiscoveryClient discoveryClient) {
+        this.restTemplate = restTemplate;
+        this.discoveryClient = discoveryClient;
+    }
+
+
+    /**
+     * <h2>通过 Ribbon 调用 Authority 服务获取 Token, [{实战使用}]</h2>
+     * */
+    public JwtToken getTokenFromAuthorityServiceByRibbon(
+            UsernameAndPassword usernameAndPassword) {
+
+        // 注意到 url 中的 ip 和端口换成了服务名称
+        String requestUrl = String.format(
+                "http://%s/ecommerce-authority-center/authority/token",
+                CommonConstant.AUTHORITY_CENTER_SERVICE_ID
+        );
+        log.info("login request url and body: [{}], [{}]", requestUrl,
+                JSON.toJSONString(usernameAndPassword));
+
+        HttpHeaders headers = new HttpHeaders();
+        headers.setContentType(MediaType.APPLICATION_JSON);
+
+        // 这里一定要使用自己注入的 RestTemplate
+        return restTemplate.postForObject(
+                requestUrl,
+                new HttpEntity<>(JSON.toJSONString(usernameAndPassword), headers),
+                JwtToken.class
+        );
+    }
+
+    /**
+     * <h2>使用原生的 Ribbon Api, 看看 Ribbon 是如何完成: 服务调用 + 负载均衡 [{学习使用}]</h2>
+     * */
+    public JwtToken thinkingInRibbon(UsernameAndPassword usernameAndPassword) {
+
+        String urlFormat = "http://%s/ecommerce-authority-center/authority/token";
+
+        // 1. 找到服务提供方的地址和端口号
+        List<ServiceInstance> targetInstances = discoveryClient.getInstances(
+                CommonConstant.AUTHORITY_CENTER_SERVICE_ID
+        );
+
+        // 构造 Ribbon 服务列表
+        List<Server> servers = new ArrayList<>(targetInstances.size());
+        targetInstances.forEach(i -> {
+            servers.add(new Server(i.getHost(), i.getPort()));
+            log.info("found target instance: [{}] -> [{}]", i.getHost(), i.getPort());
+        });
+
+        // 2. 使用负载均衡策略实现远端服务调用
+        // 构建 Ribbon 负载实例
+        BaseLoadBalancer loadBalancer = LoadBalancerBuilder.newBuilder()
+                .buildFixedServerListLoadBalancer(servers);
+
+        // 设置负载均衡策略 - 重试的策略
+        loadBalancer.setRule(new RetryRule(new RandomRule(), 300));
+
+        // 发起请求
+        String result = LoadBalancerCommand.builder().withLoadBalancer(loadBalancer)
+                .build().submit(server -> {
+
+                    String targetUrl = String.format(
+                            urlFormat,
+                            String.format("%s:%s", server.getHost(), server.getPort())
+                    );
+                    log.info("target request url: [{}]", targetUrl);
+
+                    HttpHeaders headers = new HttpHeaders();
+                    headers.setContentType(MediaType.APPLICATION_JSON);
+
+                    String tokenStr = new RestTemplate().postForObject(
+                            targetUrl,
+                            new HttpEntity<>(JSON.toJSONString(usernameAndPassword), headers),
+                            String.class
+                    );
+
+                    return Observable.just(tokenStr);
+
+                }).toBlocking().first().toString();
+
+        return JSON.parseObject(result, JwtToken.class);
+    }
+}

dev-protocol-springcloud/dev-protocol-springcloud-communication/src/main/resources/bootstrap.yml

@@ -0,0 +1,18 @@
+# Feign 的相关配置
+feign:
+  # feign 开启 gzip 压缩
+  compression:
+    request:
+      enabled: true # 对请求的数据开启压缩
+      mime-types: text/xml,application/xml,application/json # 压缩的数据类型
+      min-request-size: 1024 # 最小多大的请求数据开启压缩
+    response:
+      enabled: true # 对响应的数据开启压缩
+  # 禁用默认的 http, 启用 okhttp
+  httpclient:
+    enabled: false
+  okhttp:
+    enabled: true
+#  # OpenFeign 集成 Hystrix
+#  hystrix:
+#    enabled: true

dev-protocol-springcloud/dev-protocol-springcloud-communication/src/main/resources/http/communication.http

@@ -17,6 +17,25 @@ Content-Type: application/json
   "password": "25d55ad283aa400af464c76d713c07ad"
 }
 
+### 通过 Ribbon 去获取 Token
+POST http://127.0.0.1:8000/ecommerce-nacos-client/communication/ribbon
+Content-Type: application/json
+
+{
+  "username": "Qinyi@imooc.com",
+  "password": "25d55ad283aa400af464c76d713c07ad"
+}
+
+
+### 通过原生 Ribbon Api 去获取 Token
+POST http://127.0.0.1:8000/ecommerce-nacos-client/communication/thinking-in-ribbon
+Content-Type: application/json
+
+{
+  "username": "Qinyi@imooc.com",
+  "password": "25d55ad283aa400af464c76d713c07ad"
+}
+
 ### 通过 OpenFeign 获取 Token
 POST http://127.0.0.1:8000/ecommerce-nacos-client/communication/token-by-feign
 Content-Type: application/json

dev-protocol-springcloud/dev-protocol-springcloud-communication/微服务通信方案.md

@@ -36,14 +36,49 @@
   - 通过注册中心(推荐Nacos)获取服务地址，可以实现负载均衡的效果
 ---
 
+## 3. Ribbon 实现微服务通信及其原理解读
 
+- 如何使用
+  - 引入依赖: spring-cloud-starter-netflix-ribbon
+  - 增强 RestTemplate @LoadBalanced 注解.使其具备负载均衡的能力
 
+- ps: 学习源码最好的方式就是对部分看懂的逻辑进行仿写
+---
+## 4. OpenFeign 的简单应用及配置
 
+- OpenFeign 是实际企业中使用更为常见的一种使用
 
+- 如何使用
+  - 引入依赖 spring-cloud-starter-openfeign
+  - 添加 @EnableFeignClients 注解, 启用 open-feign
 
+- SpringCloud OpenFeign 最常用的配置
+  - OpenFeign 开启 gzip 压缩
+  - 统一 OpenFeign 使用配置: 日志、重试、请求连接和响应时间限制
+  - 使用 okhttp 替换 httpclient(别忘了引入 okhttp 依赖)
+    - feign-okhttp
+    - 补充: okhttp 和 httpclient 的区别和优缺点
 
+- ps: 写框架或者工程加载时候的日志一般都用 debug 级别, 别总是打 info 级别的日志
+---
+- OkHttp和HttpClient都是Java语言中常用的HTTP客户端库，用于发送HTTP请求并处理响应。它们之间的区别如下：
+  - OkHttp是由Square公司开发的，而HttpClient是Apache软件基金会开发的。
+  - OkHttp的性能更快，更高效。因为它使用了连接池、请求压缩、缓存等技术，而HttpClient则需要手动进行配置和优化才能达到类似的效果。
+  - OkHttp支持SPDY（升级版的HTTP/1.1协议）和HTTP/2，而HttpClient只支持HTTP/1.1。
+  - OkHttp是基于异步请求的，而HttpClient只能使用同步请求。
+  - OkHttp的代码量更少，更加简洁易懂，而HttpClient的API更加复杂，使用起来需要更多的代码。
+  - OkHttp的优点：
+    - 高效，支持连接池、请求压缩、缓存等技术，性能更快。
+    - 支持SPDY和HTTP/2协议，可以更好地适应现代网络环境。
+    - 简单易用，代码量少，API清晰明了。
+  - HttpClient的优点：
+    - 稳定可靠，经过多年的发展和优化，被广泛使用和验证。
+    - 功能强大，支持重试、重定向、认证、代理、Cookie等功能，使用起来非常灵活。
+  - 综上所述，**OkHttp适用于对性能和效率要求比较高的场景，而HttpClient适用于功能比较复杂的场景。**
 
-
+---
+## 5. 通过 Feign 的原生 API 解析其实现原理
+- ![Feign实现流程图.png](pic/Feign实现流程图.png)
 
 
 ## OpenFeign 核心源码解析