1. 程式人生 > >實現從網頁上抓取資料(htmlparser)

實現從網頁上抓取資料(htmlparser)

package com.jscud.test;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;

import org.htmlparser.Node;
import org.htmlparser.NodeFilter;
import org.htmlparser.Parser;
import org.htmlparser.filters.NodeClassFilter;
import org.htmlparser.filters.OrFilter;
import org.htmlparser.nodes.TextNode;
import org.htmlparser.tags.LinkTag;
import org.htmlparser.util.NodeList;
import org.htmlparser.util.ParserException;
import org.htmlparser.visitors.HtmlPage;
import org.htmlparser.visitors.TextExtractingVisitor;

import com.jscud.util.LogMan; //一個日誌記錄類

/**
* 演示了Html Parse的應用.

* @author scud 
http://www.jscud.com
 (http://www.jscud.com/)
*/

public class ParseHtmlTest
{

public static void main(String[] args) throws Exception
{
String aFile = "e:/jscud/temp/test.htm";

String content = readTextFile(aFile, "GBK");

test1(content);
System.out.println("====================================");

test2(content);
System.out.println("====================================");

test3(content);
System.out.println("====================================");

test4(content);
System.out.println("====================================");

test5(aFile);
System.out.println("====================================");

//訪問外部資源,相對慢
test5("
http://www.jscud.com
 (http://www.jscud.com/)"); 
System.out.println("====================================");

}

/**
* 讀取檔案的方式來分析內容.
* filePath也可以是一個Url.

* @param resource 檔案/Url
*/
public static void test5(String resource) throws Exception
{
Parser myParser = new Parser(resource);

//設定編碼
myParser.setEncoding("GBK");

HtmlPage visitor = new HtmlPage(myParser);

myParser.visitAllNodesWith(visitor);

String textInPage = visitor.getTitle();

System.out.println(textInPage);
}

/**
* 按頁面方式處理.對一個標準的Html頁面,推薦使用此種方式.
*/
public static void test4(String content) throws Exception
{
Parser myParser;
myParser = Parser.createParser(content, "GBK");

HtmlPage visitor = new HtmlPage(myParser);

myParser.visitAllNodesWith(visitor);

String textInPage = visitor.getTitle();

System.out.println(textInPage);
}

/**
* 利用Visitor模式解析html頁面.
*
* 小優點:翻譯了<>等符號 
* 缺點:好多空格,無法提取link

*/
public static void test3(String content) throws Exception
{
Parser myParser;
myParser = Parser.createParser(content, "GBK");

TextExtractingVisitor visitor = new TextExtractingVisitor();

myParser.visitAllNodesWith(visitor);

String textInPage = visitor.getExtractedText();

System.out.println(textInPage);
}

/**
* 得到普通文字和連結的內容.

* 使用了過濾條件.
*/
public static void test2(String content) throws ParserException
{
Parser myParser;
NodeList nodeList = null;

myParser = Parser.createParser(content, "GBK");

NodeFilter textFilter = new NodeClassFilter(TextNode.class);
NodeFilter linkFilter = new NodeClassFilter(LinkTag.class);

//暫時不處理 meta
//NodeFilter metaFilter = new NodeClassFilter(MetaTag.class);

OrFilter lastFilter = new OrFilter();
lastFilter.setPredicates(new NodeFilter[] { textFilter, linkFilter });

nodeList = myParser.parse(lastFilter);

Node[] nodes = nodeList.toNodeArray();

for (int i = 0; i < nodes.length; i++)
{
Node anode = (Node) nodes[i];

String line = "";
if (anode instanceof TextNode)
{
TextNode textnode = (TextNode) anode;
//line = textnode.toPlainTextString().trim();
line = textnode.getText();
}
else if (anode instanceof LinkTag)
{
LinkTag linknode = (LinkTag) anode;

line = linknode.getLink();
//@todo ("") 過濾jsp標籤:可以自己實現這個函式
//line = StringFunc.replace(line, "<%.*%>", "");
}

if (isTrimEmpty(line))
continue;

System.out.println(line);
}
}

/**
* 解析普通文字節點.

* @param content
* @throws ParserException
*/
public static void test1(String content) throws ParserException
{
Parser myParser;
Node[] nodes = null;

myParser = Parser.createParser(content, null);

nodes = myParser.extractAllNodesThatAre(TextNode.class); //exception could be thrown here

for (int i = 0; i < nodes.length; i++)
{
TextNode textnode = (TextNode) nodes[i];
String line = textnode.toPlainTextString().trim();
if (line.equals(""))
continue;
System.out.println(line);
}

}

/**
* 讀取一個檔案到字串裡.

* @param sFileName 檔名
* @param sEncode String
* @return 檔案內容
*/
public static String readTextFile(String sFileName, String sEncode)
{
StringBuffer sbStr = new StringBuffer();

try
{
File ff = new File(sFileName);
InputStreamReader read = new InputStreamReader(new FileInputStream(ff),
sEncode);
BufferedReader ins = new BufferedReader(read);

String dataLine = "";
while (null != (dataLine = ins.readLine()))
{
sbStr.append(dataLine);
sbStr.append("\r\n");
}

ins.close();
}
catch (Exception e)
{
LogMan.error("read Text File Error", e);
}

return sbStr.toString();
}

/**
* 去掉左右空格後字串是否為空
* @param astr String
* @return boolean
*/
public static boolean isTrimEmpty(String astr)
{
if ((null == astr) || (astr.length() == 0))
{
return true;
}
if (isBlank(astr.trim()))
{
return true;
}
return false;
}

/**
* 字串是否為空:null或者長度為0.
* @param astr 源字串.
* @return boolean
*/
public static boolean isBlank(String astr)
{
if ((null == astr) || (astr.length() == 0))
{
return true;
}
else
{
return false;
}
}

}