Revert "简化代码"

This reverts commit 9cc5287743.

webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientDownloader.java

@@ -32,21 +32,24 @@ import us.codecraft.webmagic.utils.HttpClientUtils;
  */
 public class HttpClientDownloader extends AbstractDownloader {
 
+    private Logger logger = LoggerFactory.getLogger(getClass());
+
     private final Map<String, CloseableHttpClient> httpClients = new HashMap<String, CloseableHttpClient>();
-    private final Logger logger = LoggerFactory.getLogger(getClass());
-    private final HttpClientGenerator httpClientGenerator = new HttpClientGenerator();
+
+    private HttpClientGenerator httpClientGenerator = new HttpClientGenerator();
 
     private HttpUriRequestConverter httpUriRequestConverter = new HttpUriRequestConverter();
 
     private ProxyProvider proxyProvider;
 
-    private final boolean responseHeader = true;
+    private boolean responseHeader = true;
 
+    private volatile boolean refreshProxyOnError = false;
 
-    private Predicate<Throwable> refreshProxyOnError = t -> false;
+    private Predicate<Throwable> throwablePredicate = t->false;
 
-    public void setRefreshProxyOnError(Predicate<Throwable> proxyOnError) {
-        this.refreshProxyOnError = refreshProxyOnError;
+    public void setThrowablePredicate(Predicate<Throwable> predicate){
+        this.throwablePredicate = predicate;
     }
 
     public void setHttpUriRequestConverter(HttpUriRequestConverter httpUriRequestConverter) {