Summary of Path Problems in Java Web Development

(1)WebSeveral Basic concepts of path in development

Assume that the following page is accessed in the browser,1As shown in: 

Figure1

EclipseDirectory structure2As shown in:

 

Figure2

The basic concepts of the website are described as follows:

1.WebRoot directory of the site:Http: // localhost: 8080/

2.WebApplicationProgramThe root directory:Http: // localhost: 8080/test/

3.Same level directory:Http: // localhost: 8080/test/articles/article1.jspAndHttp: // localhost: 8080/test/articles/article2.jsp Is in the same level directory.

 

2. return values of several path-related functions:

InTesturl. jspThe file Tests Three path-related functions:

1.Getrequesturi ()

2.Getcontextpath ()

3.Getservletpath ()

Result3As shown in:

 

Figure3

III.Web. xmlPath in

servlet ing /XX "/" indicates the current Web root path of the application.

If you think about this, you can draw a conclusion: AllWeb. xmlAll files describe a specificWebApplication Deployment information,/"Can only represent the currentWebThe root path of the application, instead of pointingWebRoot directory of the site

4. Path Problems in forwarding and redirection

1. if no" / " , for example, request. getrequestdispatcher ("hello. JSP "). forward (request, response) and response. sendredirect ("hello. JSP ") indicates searching in the same level directory login. JSP file.

2.If the path contains"/"(Note:"/"Is the first"/")

A,Forwarding

For exampleRequest. getrequestdispatcher ("/Hello. jsp"). Forward (request, response): RepresentsHttp: // localhost: 8080/test/Directory SearchHello. jspFile.

B,Redirection

For exampleResponse. sendredirect ("/Hello. jsp "): RepresentsHttp: // localhost: 8080/ Search under directoryHello. jspFile

 

5.

or " /xxx " > path

" / " indicates Web root path of the site . .

because Hyperlinks can be linked to any required target resource , SO / it definitely does not represent the current Web Root path used , but the current Web root path of the site.

6.PageTagErrorpageAttribute Path Problems

ErrorpageIf the attribute value is"/"Start,Relative to the currentWebThe root directory of the application. Otherwise, it is relative to the current page.