关于webmagic爬取Https网站报错的解决办法

目前webmagic最新版是0.7.3版本，在爬取只支持TLS1.2的https站点会报错

javax.net.ssl.SSLException: Received fatal alert: protocol_version
	at sun.security.ssl.Alerts.getSSLException(Alerts.java:208)
	at sun.security.ssl.Alerts.getSSLException(Alerts.java:154)
	at sun.security.ssl.SSLSocketImpl.recvAlert(SSLSocketImpl.java:2023)
	at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1125)
	at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1375)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1403)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1387)
	at org.apache.http.conn.ssl.SSLConnectionSocketFactory.createLayeredSocket(SSLConnectionSocketFactory.java:394)
	at org.apache.http.conn.ssl.SSLConnectionSocketFactory.connectSocket(SSLConnectionSocketFactory.java:353)
	at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:141)
	at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:353)
	at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:380)
	at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:236)
	at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:184)
	at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:88)
	at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
	at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:184)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
	at us.codecraft.webmagic.downloader.HttpClientDownloader.download(HttpClientDownloader.java:85)

作者说会在0.7.4版本发布修复错误，目前的解决办法是：

临时适配方式，修改HttpClientGenerator中的buildSSLConnectionSocketFactory方法，

return new SSLConnectionSocketFactory(createIgnoreVerifySSL(), new String[]{"SSLv3", "TLSv1", "TLSv1.1", "TLSv1.2"},
                    null,
                    new DefaultHostnameVerifier())

重写自己实现的HttpClientDownloader，并设置到Spider中。

作者原文：Https下无法抓取只支持TLS1.2的站点

我已经把源码重新编译打包了，如果自己懒得编译可以用我打包好的这个：webmagic-core-0.7.3.jar