java使用Jsoup连接网站超时的解决方法

2019-10-21 12:38java教程网 JAVA教程

jsoup是一个非常好的解析网页的包，用java开发的，提供了类似DOM，CSS选择器的方式来查找和提取文档中的内容,提取文档内容时会出现超时的情况，解决方法可看下文

今天做了一个Jsoup解析网站的项目，使用Jsoup.connect(url).get()连接某网站时偶尔会出现
java.net.SocketTimeoutException:Read timed out异常。
原因是默认的Socket的延时比较短，而有些网站的响应速度比较慢，
所以会发生超时的情况。

解决方法：

链接的时候设定超时时间即可。
doc = Jsoup.connect(url).timeout(5000).get();
5000表示延时时间设置为5s。

测试代码如下：
1，不设定timeout时：

复制代码代码如下:

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 = "//www.zzvips.com";
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());
}
}

有时发生超时：
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 设定了则一般不会超时

复制代码代码如下:

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 = "//www.zzvips.com";
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());
}
}