request initialization problem

totlechao3

HttpServletRequest request = null;
request.setCharacterEncoding ("GB2312");
HttpSession session = request.getSession ();
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Error reported: java.lang.NullPointerException
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How is request initialized not null?

kuhantian

Your code should be written in the servlet's doGet () or doPost () method. The request is instantiated by the servlet container. You only need to use it and do not require our programmer to initialize it. Please remove your HttpServletRequest request = null;
If you can use it directly in jsp. request is an implicit object of jsp.

carelee721

request is one of the implicit objects of jsp, no initialization required

zhouyongzun

I wonder if your request is used in doGet, doPost and other methods or DAO for general data operations? If it is in the doGet and doPost methods, this kind of exception does not usually occur. If it is in DAO, declare it in the parameter line of the function.
such as
public void myMethod (HttpServletRequest request) {
   // do somethings
}
Then in and out of the servlet or Aciton, the object of the HttpservletRequest declared in the function header can be used. It should not be wrong.

totlechao3

Then I will call myMethod, and pass parameters to him. What is it?
What I did was a single class, which took out the contents of the database and put it in the session, without using the servlet's doGet, doPost and other methods.