Java的HttpURLConnection类post带参

package an;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.Map.Entry;

import org.htmlparser.Parser;
import org.htmlparser.beans.StringBean;
import org.htmlparser.util.ParserException;

public class HttpUtil {

public String http(String url, HashMap<String, String> params) throws ParserException {
URL u = null;
HttpURLConnection con = null;
// 构建请求参数
StringBuffer sb = new StringBuffer();
if (params != null) {
for (Entry<String, String> e : params.entrySet()) {
sb.append(e.getKey());
sb.append("=");
sb.append(e.getValue());
sb.append("&");
}
//sb.substring(0, sb.length() - 1);
sb=sb.deleteCharAt(sb.length() - 1);
}
//System.out.println("send_url:" + url);
//System.out.println("send_data:" + sb.toString());
// 尝试发送请求
try {
u = new URL(url);
con = (HttpURLConnection) u.openConnection();
//// POST 只能为大写，严格限制，post会不识别
con.setRequestMethod("POST");
con.setDoOutput(true);
con.setDoInput(true);
con.setUseCaches(false);
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
OutputStreamWriter osw = new OutputStreamWriter(con.getOutputStream(), "UTF-8");
osw.write(sb.toString());
osw.flush();
osw.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (con != null) {
con.disconnect();
}
}

// 读取返回内容
StringBuffer buffer = new StringBuffer();
try {
//一定要有返回值，否则无法把请求发送给server端。
BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream(), "UTF-8"));
String temp;
while ((temp = br.readLine()) != null) {
buffer.append(temp);
buffer.append("\n");
}
} catch (Exception e) {
e.printStackTrace();
}
//用parser解析输出内容
StringBean sBean = new StringBean ();
sBean.setLinks (false);//设置不需要得到页面所包含的链接信息
sBean.setReplaceNonBreakingSpaces(true);//设置将不间断空格由正规空格所替代
sBean.setCollapse(true);//设置将一序列空格由一个单一空格所代替
Parser parser = new Parser();
parser.setInputHTML(buffer.toString());
parser.reset ();
parser.visitAllNodesWith (sBean);
String text = sBean.getStrings ();
return text;
}

public static void main(String[]args) throws ParserException{
HashMap<String, String> parames = new HashMap<String, String>();
parames.put("usrname", "my");
parames.put("password", "123");
HttpUtil hu=new HttpUtil();
String ret=hu.http("http://mail.163.com/", parames);
System.out.println(ret);
}

}