Generating the Server 

Response: HTTP Status Codes

Example HTTP 1.1 Response

HTTP/1.1 

200

OK

Content Type: text/html

...

Changing the status code lets you perform a 

number of tasks not otherwise possible

Forward client to another page

Indicate a missing resource

Instruct browser to use cached copy

Set status before sending document

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Servlets

www.corewebprogramming.com

Setting Status Codes

public void setStatus(int statusCode) 

Use a constant for the code, not an explicit int.

Constants are in HttpServletResponse

Names derived from standard message.

E.g., SC_OK, SC_NOT_FOUND, etc.

public void sendError(int code, 

String message) 

Wraps message inside small HTML document

public void sendRedirect(String url) 

Relative URLs permitted in 2.2/2.3

Also sets Location header

50

Servlets

www.corewebprogramming.com

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