一直知道WEB登录之后是通过session保持回话的，现在安卓却不知道怎么弄了。

研究了一下，记录一下。直接上代码：

服务器端：

index.jsp

<%@page import="java.io.PrintWriter"%>
<%@page import="com.sun.org.apache.xml.internal.serialize.Printer"%>
<%@page import="com.google.gson.JsonObject"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%
	//测试，只用一个用户名登录，不设密码
	String userName = request.getParameter("userName");

	PrintWriter pw = response.getWriter();
	//只要用户名符合集可登录
	if(userName.equals("miquan")) {
		//返回安卓端的json
		JsonObject json = new JsonObject();
		json.addProperty("success", true);
		json.addProperty("sessionId", request.getSession().getId());
		
		//保存在服务器端的session
		request.getSession().setAttribute("userName", "I am a test name.");
		
		pw.write(json.toString());
		pw.flush();
	} else {
		JsonObject obj = new JsonObject();
		obj.addProperty("success", false);
		pw.write(obj.toString());
		pw.flush();
	}
%>

<%@page import="javax.websocket.Session"%>
<%@page import="java.io.PrintWriter"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%
	PrintWriter pw = response.getWriter();
	//获取到同一个session，而不是从新生成一个session，这样就达到我要的效果了
	pw.write((String)session.getAttribute("userName"));
	pw.flush();
%>

			//登录
			btnLogin.setOnClickListener(new OnClickListener() {
				@Override
				public void onClick(View v) {
					FinalHttp fh = new FinalHttp();
					fh.get("http://172.27.35.1:8080/login/index.jsp?userName=miquan", new AjaxCallBack<Object>() {
						@Override
						public void onSuccess(Object t) {
							//获取返回来的json
							String str = t.toString();
							str = str.trim();
							try {
								JSONObject obj = new JSONObject(str);
								boolean success = obj.getBoolean("success");
								//登录成功
								if(success) {
									//app = (MyApplication) this.getApplication();
									//MyApplication添加了属性sessionId和isLogin
									app.setLogin(true);
									app.setSessionId(obj.getString("sessionId"));
									Toast.makeText(app, "登录成功", Toast.LENGTH_SHORT).show();
								} else {
									Toast.makeText(app, "登录失败", Toast.LENGTH_SHORT).show();
								}
							} catch (JSONException e) {
								e.printStackTrace();
							}
							super.onSuccess(t);
						}
						@Override
						public void onFailure(Throwable t, int errorNo,
								String strMsg) {
							Log.e("miquan", "failure  " + strMsg);
							super.onFailure(t, errorNo, strMsg);
						}
					});
				}
			});

			//测试
			btnSession.setOnClickListener(new OnClickListener() {
				@Override
				public void onClick(View v) {
					FinalHttp fh = new FinalHttp();
					//添加session，连请求一起发送，这里服务器用的是java开发的
					fh.addHeader("Cookie", "JSESSIONID=" + app.getSessionId());
					fh.get("http://172.27.35.1:8080/login/session.jsp", new AjaxCallBack<Object>() {
						@Override
						public void onSuccess(Object t) {
							Log.e("miquan", t.toString());
							super.onSuccess(t);
						}
						@Override
						public void onFailure(Throwable t, int errorNo,
								String strMsg) {
							Log.e("miquan", "failure  " + strMsg);
							super.onFailure(t, errorNo, strMsg);
						}
					});
				}
			});