FeignClient的fallbackFactory属性，服务降级。

Author: enjoyCoding666

eureka-client/pom.xml

@@ -4,7 +4,7 @@
     <modelVersion>4.0.0</modelVersion>
 
     <groupId>com.example</groupId>
-    <artifactId>demo</artifactId>
+    <artifactId>provider</artifactId>
     <version>0.0.1-SNAPSHOT</version>
     <packaging>jar</packaging>
 
@@ -30,6 +30,12 @@
             <artifactId>spring-boot-starter-integration</artifactId>
         </dependency>
 
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpcore</artifactId>
+            <version>4.4</version>
+        </dependency>
+
         <dependency>
             <groupId>mysql</groupId>
             <artifactId>mysql-connector-java</artifactId>

eureka-client/src/main/java/com/example/demo/controller/UserController.java

@@ -0,0 +1,17 @@
+package com.example.demo.controller;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class UserController {
+
+        @GetMapping("/user/name")
+        public void getUserName( ) throws Exception {
+            System.out.println("==================================================================>getUserName( )");
+            throw  new Exception("getUserNameException");
+        }
+
+
+
+}

eureka-client/src/main/resources/application.yml

@@ -11,5 +11,5 @@ eureka:
   client:
     serviceUrl:
       #  指定服务注册中心的位置
-#      defaultZone:  http://localhost:1111/eureka/
-       defaultZone:  http://peer1:1111/eureka/,http://peer2:1112/eureka/
+      defaultZone:  http://localhost:1111/eureka/
+#       defaultZone:  http://peer1:1111/eureka/,http://peer2:1112/eureka/

eureka-consumer-feign/pom.xml

@@ -47,6 +47,11 @@
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
         </dependency>
+
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+        </dependency>
     </dependencies>
 
     <!--指定springCloud版本-->

eureka-consumer-feign/src/main/java/com/example/demo/controller/DcController.java

@@ -1,6 +1,6 @@
 package com.example.demo.controller;
 
-import com.example.demo.feignInterface.DcClient;
+import com.example.demo.feignInterface.dc.DcClient;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;

eureka-consumer-feign/src/main/java/com/example/demo/controller/UserController.java

@@ -0,0 +1,21 @@
+package com.example.demo.controller;
+
+import com.example.demo.feignInterface.user.UserFeignClient;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class UserController {
+
+    @Autowired
+    private UserFeignClient userFeignClient;
+
+    @GetMapping("user/name")
+    public  String getUserName(){
+        return userFeignClient.getUserName();
+    }
+
+}
+
+

eureka-consumer-feign/src/main/java/com/example/demo/feignInterface/ClientHystrix.java renamed to eureka-consumer-feign/src/main/java/com/example/demo/feignInterface/dc/ClientHystrix.java

@@ -1,4 +1,4 @@
-package com.example.demo.feignInterface;
+package com.example.demo.feignInterface.dc;
 
 import org.springframework.stereotype.Component;
 

eureka-consumer-feign/src/main/java/com/example/demo/feignInterface/dc/ClientHystrixFallbackFactory.java

@@ -0,0 +1,15 @@
+package com.example.demo.feignInterface.dc;
+
+import feign.hystrix.FallbackFactory;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Component;
+
+@Component
+@Slf4j
+public class ClientHystrixFallbackFactory  implements FallbackFactory<DcClient> {
+    @Override
+    public DcClient create(Throwable cause) {
+        log.error(" fallback reason was: {} " , cause.getMessage());
+        return new DcClientFallbackFactory();
+    }
+}

eureka-consumer-feign/src/main/java/com/example/demo/feignInterface/DcClient.java renamed to eureka-consumer-feign/src/main/java/com/example/demo/feignInterface/dc/DcClient.java

@@ -1,4 +1,4 @@
-package com.example.demo.feignInterface;
+package com.example.demo.feignInterface.dc;
 
 import org.springframework.cloud.netflix.feign.FeignClient;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -11,7 +11,8 @@
  * 使用@FeignClient注解。其中的value指定这个接口所要调用的服务名称，fallback指定hystrix的回调类
  * 接口中定义的各个函数使用Spring MVC的注解就可以来绑定服务提供方的REST接口
  */
-@FeignClient(value = "eureka-client",fallback = ClientHystrix.class)
+//@FeignClient(value = "eureka-client",fallback = ClientHystrix.class)
+@FeignClient(value = "eureka-client",fallbackFactory = ClientHystrixFallbackFactory.class)
 public interface DcClient {
      @GetMapping(value = "/dc")
      String consumer();

eureka-consumer-feign/src/main/java/com/example/demo/feignInterface/dc/DcClientFallbackFactory.java

@@ -0,0 +1,12 @@
+package com.example.demo.feignInterface.dc;
+
+import org.springframework.stereotype.Component;
+
+@Component
+public class DcClientFallbackFactory implements DcClient {
+    @Override
+    public String consumer() {
+        String test="DcClientFallbackFactory";
+        return test;
+    }
+}

eureka-consumer-feign/src/main/java/com/example/demo/feignInterface/user/UserClientFallbackFactory.java

@@ -0,0 +1,15 @@
+package com.example.demo.feignInterface.user;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Component;
+
+@Component
+@Slf4j
+public class UserClientFallbackFactory implements UserFeignClient {
+
+    @Override
+    public String getUserName() {
+        log.debug("=======================>UserClientFallbackFactoryTest");
+        return "UserClientFallbackFactoryTest";
+    }
+}

eureka-consumer-feign/src/main/java/com/example/demo/feignInterface/user/UserFeignClient.java

@@ -0,0 +1,15 @@
+package com.example.demo.feignInterface.user;
+
+import org.springframework.cloud.netflix.feign.FeignClient;
+import org.springframework.web.bind.annotation.GetMapping;
+
+
+/**
+ *  使用fallbackFactory捕获异常，并进行服务降级。
+ */
+@FeignClient(value = "eureka-client",fallbackFactory = UserHystrixFallbackFactory.class)
+public interface UserFeignClient {
+
+    @GetMapping(value = "/user/name")
+    String getUserName();
+}

eureka-consumer-feign/src/main/java/com/example/demo/feignInterface/user/UserHystrixFallbackFactory.java

@@ -0,0 +1,29 @@
+package com.example.demo.feignInterface.user;
+
+import feign.hystrix.FallbackFactory;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Component;
+
+/**
+ * 服务降级，
+ */
+@Slf4j
+@Component
+public class UserHystrixFallbackFactory  implements FallbackFactory<UserFeignClient> {
+
+    @Override
+    public UserFeignClient create(Throwable cause) {
+        log.info("fallback reason was: {} ", cause.getMessage());
+
+        return new UserClientFallbackFactory();
+        //也可以不写UserClientFallbackFactory类，直接写成以下形式：
+//        return new UserFeignClient() {
+//            @Override
+//            public String getUserName() {
+//                return "降级信息";
+//            }
+//        };
+
+    }
+
+}

eureka-consumer-feign/src/main/java/com/example/demo/pojo/User.java

@@ -0,0 +1,17 @@
+package com.example.demo.pojo;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+@Builder
+public class User {
+    private Integer id;
+    private String name;
+
+
+}

eureka-consumer-feign/src/test/java/com/example/demo/UserTest.java

@@ -0,0 +1,10 @@
+package com.example.demo;
+
+import com.example.demo.pojo.User;
+
+public class UserTest {
+    public static void main(String[] args) {
+        User user=User.builder().id(2).name("lin").build();
+        System.out.println(user.getId());
+    }
+}