集成Feign简化调用

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

@@ -34,12 +34,6 @@
             <artifactId>mini-spring-cloud-load-balancer</artifactId>
         </dependency>
 
-        <dependency>
-            <groupId>io.github.openfeign</groupId>
-            <artifactId>feign-core</artifactId>
-            <scope>test</scope>
-        </dependency>
-
         <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-feign</artifactId>

mini-spring-cloud-load-balancer/pom.xml

@@ -54,7 +54,6 @@
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
-            <scope>test</scope>
         </dependency>
 
         <dependency>

mini-spring-cloud-openfeign/pom.xml

@@ -0,0 +1,65 @@
+<?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">
+    <parent>
+        <artifactId>mini-spring-cloud</artifactId>
+        <groupId>com.github</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>mini-spring-cloud-openfeign</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.github</groupId>
+            <artifactId>mini-spring-cloud-load-balancer</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>io.github.openfeign</groupId>
+            <artifactId>feign-core</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-configuration-processor</artifactId>
+            <optional>true</optional>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot</artifactId>
+            <optional>true</optional>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-autoconfigure</artifactId>
+            <optional>true</optional>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter</artifactId>
+            <optional>true</optional>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-commons</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-context</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+    </dependencies>
+
+</project>

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

@@ -0,0 +1,18 @@
+package com.github.cloud.openfeign;
+
+import org.springframework.context.annotation.Import;
+
+import java.lang.annotation.*;
+
+/**
+ * 启用Feign
+ *
+ * @author derek(易仁川)
+ * @date 2022/4/7
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.TYPE)
+@Documented
+@Import(FeignClientsRegistrar.class)
+public @interface EnableFeignClients {
+}

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

@@ -0,0 +1,17 @@
+package com.github.cloud.openfeign;
+
+/**
+ * Feign客户端注解
+ *
+ * @author derek(易仁川)
+ * @date 2022/4/7
+ */
+public @interface FeignClient {
+
+    /**
+     * 服务提供者应用名称
+     *
+     * @return
+     */
+    String value();
+}

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

@@ -0,0 +1,52 @@
+package com.github.cloud.openfeign;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.FactoryBean;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
+
+/**
+ * 生成Feign客户端的FactoryBean
+ *
+ * @author derek(易仁川)
+ * @date 2022/4/7
+ */
+public class FeignClientFactoryBean implements FactoryBean<Object>, ApplicationContextAware {
+
+    private String contextId;
+
+    private Class<?> type;
+
+    private ApplicationContext applicationContext;
+
+    @Override
+    public Object getObject() throws Exception {
+        return null;
+    }
+
+    @Override
+    public Class<?> getObjectType() {
+        return this.type;
+    }
+
+    @Override
+    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
+        this.applicationContext = applicationContext;
+    }
+
+    public String getContextId() {
+        return contextId;
+    }
+
+    public void setContextId(String contextId) {
+        this.contextId = contextId;
+    }
+
+    public Class<?> getType() {
+        return type;
+    }
+
+    public void setType(Class<?> type) {
+        this.type = type;
+    }
+}

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

@@ -0,0 +1,45 @@
+package com.github.cloud.openfeign;
+
+import cn.hutool.core.util.ClassUtil;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.beans.factory.support.GenericBeanDefinition;
+import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
+import org.springframework.core.type.AnnotationMetadata;
+import org.springframework.util.ClassUtils;
+
+import java.util.Set;
+
+/**
+ * 往bean容器中注册Feign客户端
+ *
+ * @author derek(易仁川)
+ * @date 2022/4/7
+ */
+public class FeignClientsRegistrar implements ImportBeanDefinitionRegistrar {
+
+    /**
+     * 往bean容器中注册Feign客户端
+     *
+     * @param importingClassMetadata
+     * @param registry
+     */
+    @Override
+    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
+        //为FeignClient注解修饰的接口生成代理bean即Feign客户端，并注册到bean容器
+        String packageName = ClassUtils.getPackageName(importingClassMetadata.getClassName());
+        //扫描所有被FeignClient注解修饰的接口
+        Set<Class<?>> classes = ClassUtil.scanPackageByAnnotation(packageName, FeignClient.class);
+        for (Class<?> clazz : classes) {
+            GenericBeanDefinition beanDefinition = new GenericBeanDefinition();
+            //使用FeignClientFactoryBean生成Feign客户端
+            beanDefinition.setBeanClass(FeignClientFactoryBean.class);
+            String clientName = clazz.getAnnotation(FeignClient.class).value();
+            beanDefinition.getPropertyValues().addPropertyValue("contextId", clientName);
+            beanDefinition.getPropertyValues().addPropertyValue("type", clazz);
+
+            //将Feign客户端注册进bean容器
+            String beanName = clazz.getName();
+            registry.registerBeanDefinition(beanName, beanDefinition);
+        }
+    }
+}

pom.xml

@@ -22,6 +22,7 @@
         <module>mini-spring-cloud-examples/mini-spring-cloud-provider-example</module>
         <module>mini-spring-cloud-examples/mini-spring-cloud-consumer-examples</module>
         <module>mini-spring-cloud-load-balancer</module>
+        <module>mini-spring-cloud-openfeign</module>
     </modules>
 
     <properties>
@@ -29,6 +30,7 @@
         <fastjson.version>1.2.79</fastjson.version>
         <hutool.version>5.7.21</hutool.version>
         <ribbon.version>2.3.0</ribbon.version>
+        <feign.version>11.8</feign.version>
     </properties>
 
     <dependencyManagement>
@@ -90,6 +92,12 @@
                 <artifactId>ribbon-core</artifactId>
                 <version>${ribbon.version}</version>
             </dependency>
+
+            <dependency>
+                <groupId>io.github.openfeign</groupId>
+                <artifactId>feign-core</artifactId>
+                <version>${feign.version}</version>
+            </dependency>
         </dependencies>
     </dependencyManagement>