JAVA代碼模擬獲取cookie以及攜帶cookie

去年做android的時候，網(wǎng)絡(luò)連接沒有用類似OKHttp之類的框架，而是完全用jdk自帶的api實現(xiàn)，今天不想看書。。就把筆記整理一下吧。。

這里有個小demo，是先實現(xiàn)登陸，登陸的過程是通過post方式請求，登陸后通過攜帶的cookie判斷是否已經(jīng)成功登陸。

1.獲取cookie

public void connect(String u) throws IOException{
        HttpURLConnection conn = null;
        OutputStream os = null;
        InputStream is = null;
        try {
            URL url = new URL(u);
            conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            conn.setDoInput(true);
            conn.setDoOutput(true);
            os = conn.getOutputStream();
            String param = "account=senninha&password=senninha";
            String eparam = param;
            //這里是把post參數(shù)攜帶上去。
            os.write(eparam.getBytes("utf-8"));
            is = conn.getInputStream();
            byte[] b = new byte[1024];
            int len = is.read(b);
            while(len != -1){
                System.out.println(new String(b,0,len,"utf-8"));
                len = is.read(b);
            }
            //這里是讀取第一次登陸時服務(wù)器返回的cookie，然后用一個全局變量cookie接收。因為是服務(wù)器往客戶端發(fā)送cookie，所以名字是Set-Cookie
            cookie = conn.getHeaderField("Set-Cookie");
            System.out.println("read over" + cookie);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }   finally{
            if(os != null){
                os.close();
            }
            
            if(is != null){
                is.close();
            }
            if(conn != null){
                conn.disconnect();
            }
            
            System.out.println("all close");
        }
    }

2.攜帶cookie

public void isLogin(String u) throws IOException{
        HttpURLConnection conn = null;
        InputStream is = null;
        try {
            URL url = new URL(u);
            conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            //把上一步獲取的cookie攜帶上去
            conn.setRequestProperty("cookie", cookie);
            conn.setDoInput(true);
            is = conn.getInputStream();
            byte[] b = new byte[1024];
            int len = is.read(b);
            while(len != -1){
                System.out.println(new String(b,0,len,"utf-8"));
                len = is.read(b);
            }
            System.out.println("read over");
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }   finally{
            if(is != null){
                is.close();
            }
            if(conn != null){
                conn.disconnect();
            }
            
        }
            System.out.println("all close");
        }

ok，以后每次訪問，只要攜帶上這個cookie，就可以暢通無阻了。當然，是指用cookie維持登陸的網(wǎng)站。

ps：java后端的維持登陸狀態(tài)的cookie叫JSESSIONID，php的叫phpSessionId好像。。
ps：對于安卓客戶端來說，獲取到的cookie可以存到數(shù)據(jù)庫里，這樣重啟app后一樣可以再次保持登陸狀態(tài)。