1，HttpClient
利用apache的虚拟客户端包获取某个地址的内容
 1 import  java.io.UnsupportedEncodingException;
  2 import  java.util.HashSet;
  3 import  java.util.Iterator;
  4 import  java.util.Set;
  5 import  java.util.regex.Matcher;
  6 import  java.util.regex.Pattern;
  7
 8 import  org.apache.commons.httpclient.HttpClient;
  9 import  org.apache.commons.httpclient.NameValuePair;
 10 import  org.apache.commons.httpclient.methods.PostMethod;
 11
12 public   class  catchMain  {
13
14    /** *//**
15     * @param args
16     */
17    public static void main(String[] args) {
18        
19
20        String url = "http://search.foodqs.com/companysearch.asp";
21        String keyword="食";
22        String response=createhttpClient(url,keyword);
23    }
24
25public static String createhttpClient(String url,String param){
26        HttpClient client = new HttpClient();
27        String response=null;
28        String keyword=null;
29        PostMethod postMethod = new PostMethod(url);
30        try {
31            if(param!=null)
32           keyword = new String(param.getBytes("gb2312"),"ISO-8859-1");
33        } catch (UnsupportedEncodingException e1) {
34            // TODO Auto-generated catch block
35            e1.printStackTrace();
36        }
37        
38        NameValuePair[] data = { new NameValuePair("keyword", keyword) };
39        // 将表单的值放入postMethod中
40        postMethod.setRequestBody(data);
41        
42        try {
43            int statusCode = client.executeMethod(postMethod);
44            response = new String(postMethod.getResponseBodyAsString()
45                    .getBytes("ISO-8859-1"), "GBK");
46        } catch (Exception e) {
47
48            e.printStackTrace();
49        }
50        return response;
51            
52    }
53        


2.java自带的HttpURLConnection


 1 public   static  String getPageContent(String strUrl, String strPostRequest,
  2              int  maxLength)  {
 3        //读取结果网页
 4        StringBuffer buffer = new StringBuffer();
 5        System.setProperty("sun.net.client.defaultConnectTimeout", "5000");
 6        System.setProperty("sun.net.client.defaultReadTimeout", "5000");
 7        try {
 8            URL newUrl = new URL(strUrl);
 9            HttpURLConnection hConnect = (HttpURLConnection) newUrl
10                    .openConnection();
11            //POST方式的额外数据
12            if (strPostRequest.length() > 0) {
13                hConnect.setDoOutput(true);
14                OutputStreamWriter out = new OutputStreamWriter(hConnect
15                        .getOutputStream());
16                out.write(strPostRequest);
17                out.flush();
18                out.close();
19            }
20            //读取内容
21            BufferedReader rd = new BufferedReader(new InputStreamReader(
22                    hConnect.getInputStream()));
23            int ch;
24            for (int length = 0; (ch = rd.read()) > -1
25                    && (maxLength <= 0 || length < maxLength); length++)
26                buffer.append((char) ch);
27            rd.close();
28            hConnect.disconnect();
29            return buffer.toString().trim();
30        } catch (Exception e) {
31            // return "错误:读取网页失败！";
32            return null;
33        }
34    }