JS
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java 网页解析工具包 Jsoup
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。
相关资料如下:
下载地址:http://jsoup.org/download
中文文档资料:http://www.open-open.com/jsoup/
比较好的文档:http://www.ostools.net/apidocs/apidoc?api=jsoup-1.6.3
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:
- 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.weather.com.cn/weather/101010400.shtml";
- 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
- 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.weather.com.cn/weather/101010400.shtml";
- 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());
- }
- }
输出为:
Time is:4158ms
Title is:顺义天气预报-今日_明日_一周天气预报:16日星期五 多云转晴 11/-4℃
http://blog.csdn.net/huangxy10/article/details/8188067
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