在applet中用HttpURLConnection 来上传文件，
现在出现一个问题，如果在eclipse中运行applet上传插件，连接tomcat上传没问题，进度条也能实现，但如果把applet放到jsp页面中，在浏览器中访问，上传就出错，进度条也有问题，
大概的问题是sessionID的原因。在用HttpURLConnection 进行上传的时候，我都会手动设置sessionID,保证同一会话，在session中会放置一个对象来保存上传的进度，applet也会有个请求不断的去访问服务器去查询这个对象，再返回上传的进度。但现在这个请求过去发现对象是空的，也就是说是个新的session，不知道为何。
在eclipse中单独运行applet，没问题。
获取SESSIONID的方法，在JSP页面中时，SESSIONID会通过jsp页面传过来
- Java code
public static String beginConnection(String url) throws Exception{ String str = null; HttpURLConnection conn = (HttpURLConnection) new URL(url) .openConnection(); conn.setDoOutput(true); conn.setDoInput(true); conn.setUseCaches(false); conn.setRequestMethod("POST"); conn.setInstanceFollowRedirects(false); conn.connect(); conn.getInputStream(); str = conn.getHeaderField("Set-Cookie"); if(str != null){ String[] session = str.split(";"); str = session[0].substring(session[0].indexOf("=") + 1); } System.out.println("sessionID-->" + str); return str; }查询进度方法
- Java code
public static String getProgress(String server, String sessionID) { String line = ""; try { URL url = new URL(server); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); conn.setDoOutput(true); conn.setDoInput(true); conn.setUseCaches(false); conn.setRequestMethod("POST"); conn.setRequestProperty("Cookie", "JSESSIONID=" + sessionID); DataOutputStream out = new DataOutputStream(conn.getOutputStream()); out.write(("folder=").getBytes("UTF-8")); out.flush(); out.close(); BufferedReader reader = new BufferedReader(new InputStreamReader( conn.getInputStream(), "UTF-8")); StringBuffer buffer = new StringBuffer(); while ((line = reader.readLine()) != null) { buffer.append(line); } reader.close(); return buffer.toString(); } catch (Exception e) { e.printStackTrace(); return null; } }文件上传的方法
- Java code
public static String upLoadFile(String server, File file, String sessionID, String folder) { System.out.println("upload sessionid-"+sessionID); String BOUNDARY = "---------7d4a6d158c954336agamacomcn"; // 定义数据分隔线 try { URL url = new URL(server); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); // 发送POST请求必须设置如下两行 conn.setDoOutput(true); conn.setDoInput(true); conn.setUseCaches(false); conn.setRequestMethod("POST"); conn.setRequestProperty("Connection", "Keep-Alive"); conn.setRequestProperty("Charset", "UTF-8"); conn.setRequestProperty("Cookie", "JSESSIONID=" + sessionID); conn.setRequestProperty("Content-Type","multipart/form-data; boundary=" + BOUNDARY); conn.setChunkedStreamingMode(BUFFER_SIZE);。。跪求解决办法，如果控制这个SESSIONID，以保证每次都是同一会话。
或者说难道说applet中用HttpURLConnection连接结束后，SESSION就销毁了？