集成Feign简化调用方式(一)

README.md

@@ -16,7 +16,7 @@
 * [服务注册](https://github.com/DerekYRC/mini-spring-cloud/blob/main/changelog.md#服务注册)
 * [服务发现](https://github.com/DerekYRC/mini-spring-cloud/blob/main/changelog.md#服务发现)
 * [负载均衡](https://github.com/DerekYRC/mini-spring-cloud/blob/main/changelog.md#集成ribbon实现客户端负载均衡)
-* [集成Feign简化调用]()
+* [集成Feign简化调用方式]()
 * [流量控制]()
 * [熔断降级]()
 * [API 网关]()

mini-spring-cloud-examples/mini-spring-cloud-consumer-examples/pom.xml

@@ -34,6 +34,11 @@
             <artifactId>mini-spring-cloud-load-balancer</artifactId>
         </dependency>
 
+        <dependency>
+            <groupId>com.github</groupId>
+            <artifactId>mini-spring-cloud-openfeign</artifactId>
+        </dependency>
+
         <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-feign</artifactId>

mini-spring-cloud-examples/mini-spring-cloud-consumer-examples/src/main/java/com/github/cloud/examples/ConsumerApplication.java

@@ -1,5 +1,6 @@
 package com.github.cloud.examples;
 
+import com.github.cloud.openfeign.EnableFeignClients;
 import com.github.cloud.tutu.discovery.TutuDiscoveryClient;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.SpringApplication;
@@ -20,6 +21,7 @@ import java.util.List;
  * @author derek(易仁川)
  * @date 2022/3/20
  */
+@EnableFeignClients
 @SpringBootApplication
 public class ConsumerApplication {
 
@@ -54,6 +56,9 @@ public class ConsumerApplication {
         @Autowired
         private RestTemplate loadBalancedRestTemplate;
 
+        @Autowired
+        private EchoService echoService;
+
         private RestTemplate restTemplate = new RestTemplate();
 
         @GetMapping("/hello")
@@ -85,6 +90,11 @@ public class ConsumerApplication {
         public String foo() {
             return loadBalancedRestTemplate.postForObject("http://provider-application/echo", null, String.class);
         }
+
+        @GetMapping("/bar")
+        public String bar() {
+            return echoService.echo();
+        }
     }
 }
 

mini-spring-cloud-examples/mini-spring-cloud-consumer-examples/src/main/java/com/github/cloud/examples/EchoService.java

@@ -0,0 +1,15 @@
+package com.github.cloud.examples;
+
+import com.github.cloud.openfeign.FeignClient;
+import org.springframework.web.bind.annotation.PostMapping;
+
+/**
+ * @author derek(易仁川)
+ * @date 2022/4/9
+ */
+@FeignClient("provider-application")
+public interface EchoService {
+
+    @PostMapping("echo")
+    String echo();
+}

mini-spring-cloud-openfeign/src/main/java/com/github/cloud/openfeign/FeignClient.java

@@ -1,11 +1,16 @@
 package com.github.cloud.openfeign;
 
+import java.lang.annotation.*;
+
 /**
  * Feign客户端注解
  *
  * @author derek(易仁川)
  * @date 2022/4/7
  */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
 public @interface FeignClient {
 
     /**

mini-spring-cloud-openfeign/src/main/java/com/github/cloud/openfeign/FeignClientFactoryBean.java

@@ -1,5 +1,7 @@
 package com.github.cloud.openfeign;
 
+import com.github.cloud.openfeign.support.SpringMvcContract;
+import feign.Feign;
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.context.ApplicationContext;
@@ -21,7 +23,9 @@ public class FeignClientFactoryBean implements FactoryBean<Object>, ApplicationC
 
     @Override
     public Object getObject() throws Exception {
-        return null;
+        return Feign.builder()
+                .contract(new SpringMvcContract())
+                .target(type, "http://localhost:1234");
     }
 
     @Override

mini-spring-cloud-openfeign/src/main/java/com/github/cloud/openfeign/support/SpringMvcContract.java

@@ -0,0 +1,46 @@
+package com.github.cloud.openfeign.support;
+
+import feign.Contract;
+import feign.MethodMetadata;
+import feign.Request;
+import org.springframework.web.bind.annotation.PostMapping;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Method;
+
+/**
+ * feign支持Spring MVC的注解
+ *
+ * @author derek(易仁川)
+ * @date 2022/4/9
+ */
+public class SpringMvcContract extends Contract.BaseContract {
+
+    @Override
+    protected void processAnnotationOnClass(MethodMetadata data, Class<?> clz) {
+        //TODO 解析接口注解
+    }
+
+    @Override
+    protected void processAnnotationOnMethod(MethodMetadata data, Annotation annotation, Method method) {
+        //解析方法注解
+        //解析PostMapping注解
+        if (annotation instanceof PostMapping) {
+            PostMapping postMapping = (PostMapping) annotation;
+            data.template().method(Request.HttpMethod.POST);
+            String path = postMapping.value()[0];
+            if (!path.startsWith("/") && !data.template().path().endsWith("/")) {
+                path = "/" + path;
+            }
+            data.template().uri(path, true);
+        }
+
+        //TODO 解析其他注解
+    }
+
+    @Override
+    protected boolean processAnnotationsOnParameter(MethodMetadata data, Annotation[] annotations, int paramIndex) {
+        //TODO 解析参数
+        return true;
+    }
+}

pom.xml

@@ -63,6 +63,12 @@
                 <version>1.0.0-SNAPSHOT</version>
             </dependency>
 
+            <dependency>
+                <groupId>com.github</groupId>
+                <artifactId>mini-spring-cloud-openfeign</artifactId>
+                <version>1.0.0-SNAPSHOT</version>
+            </dependency>
+
             <dependency>
                 <groupId>com.alibaba</groupId>
                 <artifactId>fastjson</artifactId>