java使用Jsoup連接網站超時的解決方法

今天做了一個Jsoup解析網站的項目，使用Jsoup.connect(url).get()連接某網站時偶爾會出現
java.net.SocketTimeoutException:Read timed out異常。
原因是默認的Socket的延時比較短，而有些網站的響應速度比較慢，
所以會發生超時的情況。

解決方法：

鏈接的時候設定超時時間即可。
doc = Jsoup.connect(url).timeout(5000).get();
5000表示延時時間設置為5s。

測試代碼如下：
1，不設定timeout時：

代碼如下：

package jsoupTest;

import java.io.IOException;

import org.jsoup.*;
import org.jsoup.helper.Validate;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

public class JsoupTest {
 public static  void main(String[] args) throws IOException{
 String url = "http://www.jb51.net";
 long start = System.currentTimeMillis();
 Document doc=null;
 try{
  doc = Jsoup.connect(url).get();
 }
 catch(Exception e){
  e.printStackTrace();
 }
 finally{
  System.out.println("Time is:"+(System.currentTimeMillis()-start) + "ms");
 }
 Elements elem = doc.getElementsByTag("Title");
 System.out.println("Title is:" +elem.text());
 } 
}

有時發生超時：
java.net.SocketTimeoutException: Read timed out
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at java.io.BufferedInputStream.fill(Unknown Source)
at java.io.BufferedInputStream.read1(Unknown Source)
at java.io.BufferedInputStream.read(Unknown Source)
at sun.net.www.http.ChunkedInputStream.fastRead(Unknown Source)
at sun.net.www.http.ChunkedInputStream.read(Unknown Source)
at java.io.FilterInputStream.read(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection$HttpInputStream.read(Unknown Source)
at java.util.zip.InflaterInputStream.fill(Unknown Source)
at java.util.zip.InflaterInputStream.read(Unknown Source)
at java.util.zip.GZIPInputStream.read(Unknown Source)
at java.io.BufferedInputStream.read1(Unknown Source)
at java.io.BufferedInputStream.read(Unknown Source)
at java.io.FilterInputStream.read(Unknown Source)
at org.jsoup.helper.DataUtil.readToByteBuffer(DataUtil.java:113)
at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:447)
at org.jsoup.helper.HttpConnection$Response.execute(HttpConnection.java:393)
at org.jsoup.helper.HttpConnection.execute(HttpConnection.java:159)
at org.jsoup.helper.HttpConnection.get(HttpConnection.java:148)
at jsoupTest.JsoupTest.main(JsoupTest.java:17)
Time is:3885ms
Exception in thread "main" java.lang.NullPointerException
at jsoupTest.JsoupTest.main(JsoupTest.java:25)

2 設定了則一般不會超時

代碼如下：

package jsoupTest;

import java.io.IOException;

import org.jsoup.*;
import org.jsoup.helper.Validate;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

public class JsoupTest {
 public static  void main(String[] args) throws IOException{
 String url = "http://www.jb51.net";
 long start = System.currentTimeMillis();
 Document doc=null;
 try{
  doc = Jsoup.connect(url).timeout(5000).get();
 }
 catch(Exception e){
  e.printStackTrace();
 }
 finally{
  System.out.println("Time is:"+(System.currentTimeMillis()-start) + "ms");
 }
 Elements elem = doc.getElementsByTag("Title");
 System.out.println("Title is:" +elem.text());
 } 
}