Android開發探秘之三：利用jsoup解析HTML頁面

這節主要是講解jsoup解析HTML頁面。由於在android開發過程中，不可避免的涉及到web頁面的抓取，解析，展示等等，所以，在這里我主要展示下利用jsoup jar包來抓取cnbeta.com網站的話題分類的實例。

下面是主要的代碼，由於使用及其簡單，我這里就不再多說了：

package com.android.web;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


import org.apache.http.util.ByteArrayBuffer;
import org.apache.http.util.EncodingUtils;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ListView;
import android.widget.SimpleAdapter;


public class _GetWebResoureActivity extends Activity {

	Document doc;

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		findViewById(R.id.button1).setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				load();
			}
		});
	}

	protected void load() {
		
		try {
			doc = Jsoup.parse(new URL("http://www.cnbeta.com"), 5000);
		} catch (MalformedURLException e1) {
			e1.printStackTrace();
		} catch (IOException e1) {
			e1.printStackTrace();
		}
		
		List<Map<String, String>> list = new ArrayList<Map<String, String>>();
		Elements es = doc.getElementsByClass("main_navi");
		for (Element e : es) {
			Map<String, String> map = new HashMap<String, String>();
			map.put("title", e.getElementsByTag("a").text());
			map.put("href", "http://www.cnbeta.com"
					+ e.getElementsByTag("a").attr("href"));
			list.add(map);
		}
		
		ListView listView = (ListView) findViewById(R.id.listView1);
		listView.setAdapter(new SimpleAdapter(this, list, android.R.layout.simple_list_item_2,
				new String[] { "title","href" }, new int[] {
				android.R.id.text1,android.R.id.text2
		}));
		
	}

	/** * @param urlString * @return */
	public String getHtmlString(String urlString) {
		try {
			URL url = null;
			url = new URL(urlString);

			URLConnection ucon = null;
			ucon = url.openConnection();

			InputStream instr = null;
			instr = ucon.getInputStream();

			BufferedInputStream bis = new BufferedInputStream(instr);

			ByteArrayBuffer baf = new ByteArrayBuffer(500);
			int current = 0;
			while ((current = bis.read()) != -1) {
				baf.append((byte) current);
			}
			return EncodingUtils.getString(baf.toByteArray(), "gbk");
		} catch (Exception e) {
			return "";
		}
	}
}

 

注意代碼中黃色標注部分，一定要找對位置，才能得到正確的結果。下面就是主要的預覽效果：