Jsp Tutorial: action, form/common fields

Bkjia.com jsp documentThis is another day for BUG change. Today, this is a headache, especially when it is based on other people's code. After more than two hours, I found a strange error. After reading the error for a while, I found out that I had made a naive mistake, so I did not pay attention to the details:

The correct syntax for a Form is as follows:

Reference content is as follows: <% ExpenseItemForm form = (ExpenseItemForm) request. getAttribute ("oldexpenseItemForm "); %> <Input name = "expenseItemNumber" type = "text" class = "input" Value = "<% = form. getExpenseItemNumber () %>" size = "20"> Action -------------------- ExpenseItemForm oldexpenseItemForm = new ExpenseItemForm (); OldexpenseItemForm. setExpenseItemNumber (oldexpenseItemNumber ); . . . Request. setAttribute ("oldexpenseItemForm", oldexpenseItemForm );

The correct syntax for a common field is as follows:

Reference content is as follows: <Input name = "roleId" class = "" id = "roleId" size = "22" Value = "<% = request. getAttribute (" roleId ") %>" type = "hidden"> Or <input name = "roleId" class = "" id = "roleId" size = "22" Value = "$ {roleId}" type = "hidden"> Action -------------------- Request. setAttribute ("roleId", roleId );