Java带Cookie模拟Http请求(get,post)

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.CookieManager;
import java.net.HttpURLConnection;
import java.net.URL;

/**
* @author Tony
*
*/
public class HttpClient {
CookieManager ca = new CookieManager();
String sessionID = "";

public String get(String url, String charset) {
try {
String key = "";
String cookieVal = "";

URL httpURL = new URL(url);
HttpURLConnection http = (HttpURLConnection) httpURL
.openConnection();
if (!sessionID.equals("")) {
http.setRequestProperty("Cookie", sessionID);
}
for (int i = 1; (key = http.getHeaderFieldKey(i)) != null; i++) {
if (key.equalsIgnoreCase("set-cookie")) {
cookieVal = http.getHeaderField(i);
cookieVal = cookieVal.substring(
0,
cookieVal.indexOf(";") > -1 ? cookieVal
.indexOf(";") : cookieVal.length() - 1);
sessionID = sessionID + cookieVal + ";";
}
}
BufferedReader br = new BufferedReader(new InputStreamReader(
http.getInputStream(), charset));
StringBuilder sb = new StringBuilder();
String temp = null;
while ((temp = br.readLine()) != null) {
sb.append(temp);
sb.append("\n");
}
br.close();
return sb.toString();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}

public String post(String url, String data, String charset) {
try {
URL httpURL = new URL(url);
String key = null;
String cookieVal = null;
HttpURLConnection http = (HttpURLConnection) httpURL
.openConnection();
http.setDoOutput(true);
http.setDoInput(true);
if (!sessionID.equals("")) {
http.setRequestProperty("Cookie", sessionID);
}
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
http.getOutputStream(), charset));
bw.write(data);
bw.close();
BufferedReader br = new BufferedReader(new InputStreamReader(
http.getInputStream(), charset));
StringBuilder sb = new StringBuilder();
String temp = null;
while ((temp = br.readLine()) != null) {
sb.append(temp);
sb.append("\n");
}
br.close();
for (int i = 1; (key = http.getHeaderFieldKey(i)) != null; i++) {
if (key.equalsIgnoreCase("set-cookie")) {
cookieVal = http.getHeaderField(i);
cookieVal = cookieVal.substring(0, cookieVal.indexOf(";"));
sessionID = sessionID + cookieVal + ";";
}
}
return sb.toString();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}