How can a RequestDispatcher call a servlet in another web application?

Greenhorn

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posted 21 years ago

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in the servlet specification 2.3 there is such a statement:

To illustrate this requirement with an example: if a servlet uses the RequestDispatcher to call a servlet in another web application, any sessions created for and visible to the callee servlet must be different from those visible to the calling servlet.

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Anthony Watson

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posted 21 years ago

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Use the code below to get the servlet context reference. From there, you can retrieve an appropriate RequestDispatcher.

this.getServletContext().getContext(uripath)

Anthony W. MCP, SCJP 1.4, SCJD, SCWCD 1.3, SCWCD 1.4, SCBCD

Yorck Zhou

Greenhorn

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posted 21 years ago

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Thanks Anthony!
But when I tried the following fragment code in the Tomcat 4.1. It return a NullpointerException. Is it a bug of Tomcat 4.1?

try{
ServletContext rootContext = getServletContext().getContext("http://localhost:8080/");
System.out.println( ( rootContext.getAttribute("root") ).toString() );
}catch(Exception e){
System.out.println(e);
}

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Nicholas Cheung

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posted 21 years ago

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You need to specify the context path of your Web application, not the URL that accessing your website.

Nick

SCJP 1.2, OCP 9i DBA, SCWCD 1.3, SCJP 1.4 (SAI), SCJD 1.4, SCWCD 1.4 (Beta), ICED (IBM 287, IBM 484, IBM 486), SCMAD 1.0 (Beta), SCBCD 1.3, ICSD (IBM 288), ICDBA (IBM 700, IBM 701), SCDJWS, ICSD (IBM 348), OCP 10g DBA (Beta), SCJP 5.0 (Beta), SCJA 1.0 (Beta), MCP(70-270), SCBCD 5.0 (Beta), SCJP 6.0, SCEA for JEE5 (in progress)

Yorck Zhou

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posted 21 years ago

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Yes, I have also tried a uri as an argument of the getContext() method, but it is still return a NullpointerException!

In the servlet API, I found the following statement about the getContext():

In a security conscious environment, the servlet container may return null for a given URL.

So, should make any change in the Tomcat to make it work?

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