servlet Redirection and Request forwarding

Set request redirection 1. You can select a different server-side program to process the request 2. Redirect the request to an exact URL setting automatic refresh and wait pages

response.setHeader("Refresh","time;URL=url");

The client browser sends a request to the server 1. Browser input Urk URL (get method) 2. Click the hyperlink (Get method) 3. Click Submit form (Get or POST method) The Get method and the Post method distinguish one. Commit data type get () text POST () text, Binary text two. Commit data length get () no more than 255 characters post () No limit three. Submit data visibility get () is displayed as part of the URL address in the browser address bar POST () as the requested message body, not visible four. Submit data Cache GET () Cached in Browser URL history status POST () will not be cached by the browser when using Get/post Method 1: Request a static page or graphics file. GET () 2: Send Big Data. POST () 3: Upload the file. POST () 4: Sends a user name, password, or other confidential information. POST () state Management 1. Hide Fields

缺点：必须是动态页面才有效

2.Cookie

优点：数据储存在客户端(动态页面和静态页面都有效)，用户可以进入Cookie，Cookie可以删除.缺点：不安全

3.Session (session) Professional status management

1.可以通过设置时间(超时会消亡).2.手动销毁.3.Web服务器关闭(消亡).

# #ServletContext应用上下文
# # #1. Applications that belong to the entire web
# # #2. can access the local input stream to the Web application resource
# # #3. Convert the virtual path of a resource to a physical path
# # #4. Log Event Logs
# # #5. Binds an object to be shared throughout the Web application (all Servlets are accessible)
# #虚拟路径转换为物理路径
1.getResourcePaths (java.lang.String path);
2.getResourceAsStream (java.lang.String path);
3.getResource (java.lang.String path);
# #设置请求重定向
# # #1. You can select a different server-side program to process the request
# # #2. REDIRECT the request to a completely different URL
# #设置自动刷新和等待页
Response.setheader ("Refresh", "time; Url=url ");
# #客户端浏览器向服务器发送请求方式
# # #1. Browser input Urk URL (get method)
# # #2. Click the hyperlink (Get method)
# # #3. Click Submit form (Get or POST method)
# #get方法和post方法区别
# # #一. Submit data Type GET () text POST () text, binary text
# # #二. Submit data Length GET () No more than 255 characters POST () No Limit
# # #三. Submit data Visibility GET () is displayed as part of the URL address in the browser address bar POST () as the requested message body, not visible
# # #四. Submit data Cache GET () cache in browser URL history status POST () will not be cached by the browser
# #何时使用get/post method
# # #1: Request a static page or graphics file. GET ()
# # #2: Send Big Data. POST ()
# # #3: Upload files. POST ()
# # #4: Send a user name, password, or other confidential information. POST ()

# #状态管理
# # #1. Hide Fields
Cons: Must be dynamic page only valid
# # #2. Cookies
Advantages: Data stored in the client (dynamic pages and static pages are valid), users can enter Cookie,cookie can be deleted.
Cons: unsafe
# # #3. session (conversation) professional status management
1. You can set the time (timeout will die out).
2. Manually Destroy.
3.Web server shutdown (extinction).

servlet Redirection and Request forwarding