首页微服务集成Sentinel，实现小说服务调用的熔断降级

novel-book/book-api/src/main/java/com/java2nb/novel/book/api/fallback/BookApiFallback.java

@@ -0,0 +1,57 @@
+package com.java2nb.novel.book.api.fallback;
+
+import com.java2nb.novel.book.api.BookApi;
+import com.java2nb.novel.book.entity.Book;
+import com.java2nb.novel.book.entity.BookComment;
+
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+
+/**
+ * 小说微服务API接口降级处理类（服务提供端，默认降级处理）
+ * @author xiongxiaoyang
+ * @version 1.0
+ * @since 2020/6/7
+ */
+public class BookApiFallback implements BookApi {
+    @Override
+    public List<Book> queryBookByMinUpdateTime(Date minDate, int limit) {
+        return null;
+    }
+
+    @Override
+    public List<Book> queryBookByIds(List<Long> ids) {
+        return new ArrayList<>();
+    }
+
+    @Override
+    public List<Book> listRank(Byte type, Integer limit) {
+        return null;
+    }
+
+    @Override
+    public Book queryBookById(Long id) {
+        return null;
+    }
+
+    @Override
+    public void addBookComment(Long userId, BookComment comment) {
+
+    }
+
+    @Override
+    public List<BookComment> listUserCommentByPage(Long userId, int page, int pageSize) {
+        return null;
+    }
+
+    @Override
+    public List<Book> queryNetworkPicBooks(String localPicPrefix, int limit) {
+        return null;
+    }
+
+    @Override
+    public void updateBookPic(String picUrl, Long bookId) {
+
+    }
+}

novel-common/pom.xml

@@ -22,6 +22,9 @@
             <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
         </dependency>
 
+
+
+
         <dependency>
             <groupId>io.springfox</groupId>
             <artifactId>springfox-swagger2</artifactId>

novel-common/src/main/resources/application-common.yml

@@ -21,7 +21,6 @@ spring:
 feign:
   httpclient:
     enabled: true
-
 #关掉mq的健康检查，防止某些没有用到mq的服务启动报错，个别服务如需mq监控，单独开启
 management:
   health:

novel-gateway/pom.xml

@@ -40,6 +40,11 @@
             <artifactId>spring-cloud-alibaba-sentinel-gateway</artifactId>
         </dependency>
 
+        <dependency>
+            <groupId>com.alibaba.csp</groupId>
+            <artifactId>sentinel-transport-simple-http</artifactId>
+        </dependency>
+
 
 
     </dependencies>

novel-home/pom.xml

@@ -23,12 +23,12 @@
 
 
         <dependency>
-            <groupId>org.springframework.cloud</groupId>
+            <groupId>com.alibaba.cloud</groupId>
-            <artifactId>spring-cloud-starter-openfeign</artifactId>
+            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
         </dependency>
         <dependency>
             <groupId>org.springframework.cloud</groupId>
-            <artifactId>spring-cloud-netflix-hystrix</artifactId>
+            <artifactId>spring-cloud-starter-openfeign</artifactId>
         </dependency>
 
 

novel-home/src/main/java/com/java2nb/novel/home/feign/BookFeignClient.java

@@ -1,6 +1,7 @@
 package com.java2nb.novel.home.feign;
 
 import com.java2nb.novel.book.api.BookApi;
+import com.java2nb.novel.home.feign.fallback.BookFeignFallback;
 import org.springframework.cloud.openfeign.FeignClient;
 
 /**
@@ -9,7 +10,9 @@ import org.springframework.cloud.openfeign.FeignClient;
  * @version 1.0
  * @since 2020/5/28
  */
-@FeignClient("book-service")
+
+@FeignClient(name = "book-service",fallback = BookFeignFallback.class)
 public interface BookFeignClient extends BookApi {
 
+
 }

novel-home/src/main/java/com/java2nb/novel/home/feign/fallback/BookFeignFallback.java

@@ -0,0 +1,15 @@
+package com.java2nb.novel.home.feign.fallback;
+
+import com.java2nb.novel.book.api.fallback.BookApiFallback;
+import com.java2nb.novel.home.feign.BookFeignClient;
+import org.springframework.stereotype.Service;
+
+/**
+ * 小说Feign客户端降级处理类(服务消费端，自定义降级处理)
+ * @author xiongxiaoyang
+ * @version 1.0
+ * @since 2020/6/7
+ */
+@Service
+public class BookFeignFallback extends BookApiFallback implements BookFeignClient {
+}

novel-home/src/main/resources/application.yml

@@ -1,4 +1,6 @@
 spring:
   profiles:
     include: [common]
-
+feign:
+  sentinel:
+    enabled: true

pom.xml

@@ -40,6 +40,7 @@
         <java.version>1.8</java.version>
         <spring-cloud.version>Hoxton.SR4</spring-cloud.version>
         <spring-cloud-alibaba.version>2.1.0.RELEASE</spring-cloud-alibaba.version>
+        <openfeign.version>2.2.0.RELEASE</openfeign.version>
         <nacos.version>0.2.2.RELEASE</nacos.version>
         <swagger.version>2.7.0</swagger.version>
         <maven.test.skip>true</maven.test.skip>
@@ -123,6 +124,23 @@
                 <version>${novel-author-api.version}</version>
             </dependency>
 
+            <!--在2.2.0.RELEASE里有一行注释描述，feign的SentinelContractHolder接口方法名parseAndValidatateMetadata拼写错误，
+          在2.2.2.RELEASE方法已修正了，即方法名发生了改变。
+          在spring-cloud-alibaba-sentinel中的SentinelContractHolder类，用到了该接口的这个方法
+          所以，要么降低SpringCloud版本，要么单独指定openfeign版本，否则启动报错
+          java.lang.AbstractMethodError:
+          com.alibaba.cloud.sentinel.feign.SentinelContractHolder.
+          parseAndValidateMetadata(Ljava/lang/Class;)Ljava/util/List
+          注意spring-cloud-openfeign-dependencies写在spring-cloud-dependencies前面，
+          因为dependency前面的优先生效。-->
+            <dependency>
+                <groupId>org.springframework.cloud</groupId>
+                <artifactId>spring-cloud-openfeign-dependencies</artifactId>
+                <version>${openfeign.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+
 
             <!-- springCloud -->
             <dependency>
@@ -142,6 +160,8 @@
             </dependency>
 
 
+
+
             <!--swagger-->
             <dependency>
                 <groupId>io.springfox</groupId>