return when page is null

webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java

@@ -402,6 +402,7 @@ public class Spider implements Runnable, Task {
         if (page == null) {
             sleep(site.getSleepTime());
             onError(request);
+            return;
         }
         // for cycle retry
         if (page.isNeedCycleRetry()) {

webmagic-extension/src/main/java/us/codecraft/webmagic/example/PatternProcessorExample.java

@@ -54,7 +54,7 @@ public class PatternProcessorExample {
             }
         };
 
-        CompositePageProcessor pageProcessor = new CompositePageProcessor(Site.me().setDomain("github.com").setRetryTimes(0).setSleepTime(0));
+        CompositePageProcessor pageProcessor = new CompositePageProcessor(Site.me().setDomain("github.com").setRetryTimes(3));
         CompositePipeline pipeline = new CompositePipeline();
 
         pageProcessor.setSubPageProcessors(githubRepoProcessor, githubUserProcessor);