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This article mainly shows you "what is the meaning of ServletResponse", the content is easy to understand, clear, hope to help you solve your doubts, the following let the editor lead you to study and learn "what does ServletResponse mean" this article?

What is the Servlet lifecycle?

The life cycle of general Servlet (GenericServlet, that is, protocol-independent Servlet) is init ()-> GenericServlet.service (ServletRequest req,ServletResponse res)-- > destroy.

The life cycle of HttpServlet: init ()-- > GenericServlet.service (ServletRequest req, ServletResponse res)-- > service (HttpServletRequest req, HttpServletResponse resp)-- > doXXXX ()-- > destroy.

Is it necessary to override the GenericServlet.service () method?

It is not necessary for HttpServlet. You just need to override its doXXXX () method. The service () method in HttpServlet automatically forwards the request to the corresponding doXXXX () method (such as the doGet () method) based on the user's request type.

How are ServletRequest.getReader () and ServletRequest.getInputStream () used?

Note that both methods cannot be used at the same time. The ServletRequest.getRealPath (String path) method is no longer recommended. Use the ServletContext.getRealPath (String path) method.

What is the default character set (charset) for ServletResponse?

The default character set (charset) for ServletResponse is ISO-8859-1, and the new character set can be changed through the setContentType (java.lang.String) method. Example: setContentType ("text/html; charset=Shift_JIS"). For character set information, you can browse RFC 2045

What is the difference between HttpServletRequest.getRequestURI () and HttpServletRequest.getRequestURL ()?

The return value of request.getRequestURI () is similar to: / xuejava/requestdemo.jsp

The return value of request.getRequestURL () is similar to: http://localhost:8080/xuejava/requestdemo.jsp

What is the difference between HttpServletRequest.encodeURL () and HttpServletRequest.encodeRedirectURL ()? Why are there two different ways?

When using URL-rewriting to manage Session, you need to use these two methods. The difference between the two methods is that the logic of the two methods to determine whether the session ID needs to be included is different. The encodeRedirectURL () method should be called before calling HttpServletResponse.sendRedirect, otherwise the Sesssion information may be lost.

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