servlet redirect/forward/session/cookie 與 HTTP 協議的測試

 本文直接展示servlet的測試結果。

 

servlet的代碼中使用sendRedirect：

  

public class SessionTest extends HttpServlet {
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
...
response.sendRedirect("http://localhost:8080/web/");
...}

 

 

查看瀏覽器交互過程，先是請求該servlet：

 

1. Request URL:
   http://localhost:8080/web/SessionTest
2. Request Method:
   GET
3. Status Code:
   302 Found
4. Request Headersview source
   1. Accept:
      text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
   2. Accept-Encoding:
      gzip,deflate,sdch
   3. Accept-Language:
      en-US,en;q=0.8,zh;q=0.6,ko;q=0.4,ja;q=0.2
   4. Cache-Control:
      max-age=0
   5. Connection:
      keep-alive
   6. Host:
      localhost:8080
   7. User-Agent:
      Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/27.0.1453.94 Safari/537.36
5. Response Headersview source
   1. Content-Length:
      0
   2. Content-Type:
      text/html;charset=UTF-8
   3. Date:
      Thu, 06 Jun 2013 07:16:55 GMT
   4. Location:
      http://localhost:8080/web/
   5. Server:
      Apache-Coyote/1.1
   6. Set-Cookie:
      JSESSIONID=8C8DCD7355CC62C75C9BD154B2ADEDD0; Path=/web/; HttpOnly

可以看到response返回了302，並帶上了location, 指示瀏覽器做第二次跳轉請求，瀏覽器得到提示後進行第二次請求。

 

同樣的servlet，將代碼改爲forward，實現了在servlet容器內部的跳轉，對瀏覽器實際上是不可見得。

 

request.getRequestDispatcher("/index.jsp").forward(request, response);

 

看一下tomcat服務器的響應，一個200  OK之後，直接返回了內容，很直接

1. Request URL:
   http://localhost:8080/web/SessionTest
2. Request Method:
   GET
3. Status Code:
   200 OK
4. Request Headersview source
   1. Accept:
      text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
   2. Accept-Encoding:
      gzip,deflate,sdch
   3. Accept-Language:
      en-US,en;q=0.8,zh;q=0.6,ko;q=0.4,ja;q=0.2
   4. Connection:
      keep-alive
   5. Cookie:
      JSESSIONID=4D4C34D45462707E53A475C060E2D2A2; test=test
   6. DNT:
      1
   7. Host:
      localhost:8080
   8. User-Agent:
      Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/27.0.1453.94 Safari/537.36
5. Response Headersview source
   1. Content-Length:
      218
   2. Content-Type:
      text/html;charset=UTF-8
   3. Date:
      Thu, 06 Jun 2013 09:12:04 GMT
   4. Server:
      Apache-Coyote/1.1
   5. Set-Cookie:
      JSESSIONID=0FE64A4D2D1777BD44F08F2F8186384B; Path=/web/; HttpOnly

 

再看cookie的保存，將以上代碼改爲將cookie加入response：

 

        Cookie cookie = new Cookie("test","test");
        response.addCookie(cookie);
        PrintWriter out = response.getWriter();

 

 

再看HTTP head：

 

 

1. Request URL:
   http://localhost:8080/web/SessionTest
2. Request Method:
   GET
3. Status Code:
   200 OK
4. Request Headersview source
   1. Accept:
      text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
   2. Accept-Encoding:
      gzip,deflate,sdch
   3. Accept-Language:
      en-US,en;q=0.8,zh;q=0.6,ko;q=0.4,ja;q=0.2
   4. Cache-Control:
      max-age=0
   5. Connection:
      keep-alive
   6. Cookie:
      JSESSIONID=FB43328EF48C78B7122454F84B57F164
   7. DNT:
      1
   8. Host:
      localhost:8080
   9. User-Agent:
      Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/27.0.1453.94 Safari/537.36
5. Response Headersview source
   1. Content-Length:
      186
   2. Content-Type:
      text/html;charset=UTF-8
   3. Date:
      Thu, 06 Jun 2013 07:47:13 GMT
   4. Server:
      Apache-Coyote/1.1
   5. Set-Cookie:
      JSESSIONID=BC3FDA2D942F2F4B50757D9C436D21A9; Path=/web/; HttpOnly
   6. Set-Cookie:
      test=test

Tomcat通過HTTP協議的Set-Cookie將servlet的cookie放入了響應頭，查看瀏覽器的cookie，除了jsessionid，又加了一個test/test的cookie進來。