HtmlUnit---网页抓取工具解析及使用

网页的抓取网络爬虫的核心功能之一，本文介绍一下htmlunit的使用。

1.jar包：

从链接：http://sourceforge.net/projects/htmlunit/files/htmlunit/

下载最新的bin文件 htmlunit-2.29.jar;htmlunit-core-js-2.28.jar

2.获取页面的TITLE、XML代码、文本

package htmlunit;

import java.io.IOException;

import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlPage;

public class HtmlUnitTest {
public static void main(String[] args){
String str="";
//创建一个webclient
WebClient webclient=new WebClient();
//htmlclient对css和js的支持不好，所以关闭
webclient.getOptions().setJavaScriptEnabled(false);
webclient.getOptions().setCssEnabled(false);
//获取页面
String url="http://www.weather.com.cn/alarm/newalarmlist.shtml?areaId=10126";
try {
HtmlPage page=webclient.getPage(url);
//获取标题TITLE
str=page.getTitleText();
System.out.println(str);
//获取页面xml代码
str=page.asXml();
System.out.println(str);
//获取页面文本
str=page.asText();
System.out.println(str);

} catch (FailingHttpStatusCodeException | IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//关闭webclient
webclient.close();
}

}

3.使用不同版本的浏览器打开

package htmlunit;

import java.io.IOException;

import com.gargoylesoftware.htmlunit.BrowserVersion;
import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlPage;

public class HtmlUnitTest2 {
public static void main(String[] args){
String str="";
//使用FireFox浏览器
WebClient webclient=new WebClient(BrowserVersion.FIREFOX_45);
//htmlunit对css和js支持不好，就关闭
webclient.getOptions().setCssEnabled(false);
webclient.getOptions().setJavaScriptEnabled(false);
try {
//获取页面
HtmlPage page=webclient.getPage("http://www.baidu.com/");
str = page.getTitleText();
???????System.out.println(str);
???????//关闭webclient
???????webclient.close();
???
} catch (FailingHttpStatusCodeException | IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}

4.找到页面中特定元素

package htmlunit;

import java.io.IOException;

import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlInput;
import com.gargoylesoftware.htmlunit.html.HtmlPage;

public class HtmlUnitTest3 {
public static void main(String[] args){
//创建webclient
WebClient webclient =new WebClient();
//htmlunit 对css和javascript的支持不好，所以请关闭之
webclient.getOptions().setCssEnabled(false);
webclient.getOptions().setJavaScriptEnabled(false);
try {
HtmlPage page=webclient.getPage("http://www.baidu.com/");
//通过id获得"百度一下"按钮
HtmlInput btn=(HtmlInput)page.getHtmlElementById("su");
System.out.println(btn.getDefaultValue());
//关闭webclient
webclient.close();
} catch (FailingHttpStatusCodeException | IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

}

5.元素检索

package htmlunit;

import java.io.IOException;
import java.util.List;

import com.gargoylesoftware.htmlunit.BrowserVersion;
import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlDivision;
import com.gargoylesoftware.htmlunit.html.HtmlInput;
import com.gargoylesoftware.htmlunit.html.HtmlPage;

public class HtmlClientTest4 {

public static void main(String[] args){
WebClient webclient =new WebClient(BrowserVersion.CHROME);
webclient.getOptions().setCssEnabled(false);
webclient.getOptions().setJavaScriptEnabled(false);
try {
HtmlPage page=webclient.getPage("http://www.baidu.com/");
//查找所有div
List<?> hbList = (List) page.getByXPath("//div");
HtmlDivision hb=(HtmlDivision) hbList.get(0);
System.out.println(hb.toString());
//查找并获取特定input
List<?> inputList=page.getByXPath("//input[@id=‘su‘]");
HtmlInput input=(HtmlInput) inputList.get(0);
System.out.println(input.toString());
//关闭webclient
webclient.close();
} catch (FailingHttpStatusCodeException | IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

6.提交搜索

package htmlunit;

import java.io.IOException;

import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlInput;
import com.gargoylesoftware.htmlunit.html.HtmlPage;

public class HtmlUntilTest5 {
public static void main(String args[]){
WebClient webclient=new WebClient();
webclient.getOptions().setCssEnabled(false);
webclient.getOptions().setJavaScriptEnabled(false);
try {
HtmlPage page=webclient.getPage("http://www.baidu.com/");
//获取搜索输入框并提交搜索内容
HtmlInput input=page.getHtmlElementById("kw");
System.out.println(input.toString());
input.setValueAttribute("HtmlUnit 下载");
System.out.println(input.toString());
//获取搜索按钮并点击
HtmlInput btn=(HtmlInput) page.getElementById("su");
HtmlPage page2=btn.click();
//输出新页面的文本
System.out.println(page2.asText());
} catch (FailingHttpStatusCodeException | IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

}