Use request.getParameter (String) method to get the form to submit data
Chinese garbage problem occured when submitting data
Solution,
1, the first character string to break iso-8859-1 format, and then makes up a new utf-8 format string
2, by request.setCharacterEncoding ( "utf-8"); Method
Receives data normally results
User name and password is incorrect login failures, failed login using a redirect, url URL location will change, and will display data request carries the information
Interface of successful login, use URL forwarding url points to does not change, and does not appear to carry the data request
userLogin.jsp to determine whether the login success page, login.jsp after a successful login page, loginSuccess.jsp to login page
Save Username
Displays the user login name after success
Click to log out, return to the login page, open home has been empty session, use removeAttribute (String key) to clear only in the session key, id does not clear itself
Analysis: By session.setAttribute (String key, String value); save data
Getting a property value; by session.getAttribute (String key)
Delete data; by session.removeAttribute (String key)
session.getId (): Gets the session id
Login Home reopen closed successfully, findings show signed in
Each time you refresh or reopen the page, the number will be +1
