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This article mainly explains "how to achieve login and registration functions in java+mysql". Friends who are interested may wish to have a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "how to log in and register with java+mysql".

1. First of all, the account password input box and button:

Login:

Account number: password: not registered yet? Click to register

Registration:

Register a new user * username * password * confirm password Email returns to the login page

Both form tables have action in their attributes, which can be understood to be used to mark login and registration, and bind to the corresponding servlet in web.xml.

2. Create tables in the database and insert data

Open MySQL in the server and build the table

Create table login (uname char (15) primary key,password char (15) not null,email char (20))

3. The sql statement is embedded in the java statement to find (login) and insert (register) user information. The following class names are the names of the files.

Login:

Import java.sql.*;public class userlogin {String drv = "com.mysql.jdbc.Driver"; String url = "jdbc:mysql://localhost:3306/login"; String usr = "root"; String pwd = "* *"; / / your password public boolean isuserlogin (String id,String password) {boolean isValid = false; String sql= "select * from ulogin where uname='" + id+ "'and password='" + password+ "'" Try {Class.forName (drv). NewInstance (); Connection conn = DriverManager.getConnection (url,usr,pwd); Statement stm = conn.createStatement (); ResultSet rs = stm.executeQuery (sql); if (rs.next ()) {isValid = true;} rs.close (); stm.close () Conn.close ();} catch (Exception e) {e.printStackTrace (); System.out.println (e);} if (isValid) {/ / determine whether the user name and password match the settings return true;} else return false;}}

Registration:

Import java.sql.*;public class register {String drv = "com.mysql.jdbc.Driver"; String url = "jdbc:mysql://localhost:3306/login"; String usr = "root"; String pwd = "* *"; public boolean userregister (String id,String password,String email) {boolean b = false; String sql = "select * from ulogin where uname='" + id+ "'" Try {Class.forName (drv). NewInstance (); Connection conn = DriverManager.getConnection (url,usr,pwd); Statement stm = conn.createStatement (); ResultSet rs = stm.executeQuery (sql) If (! rs.next ()) {sql = "insert into ulogin (uname,password,email) values ('" + id+ ",'" + password+ "','" + email+ "')"; stm.execute (sql); b = true;} rs.close (); stm.close (); conn.close () } catch (Exception e) {e.printStackTrace (); System.out.println (e);} if (b) {return true;} else return false;}}

4. Build a servlet to handle transactions. If the connection database lookup is successful, the login is successful, otherwise it fails; if the registration is successful, return to the login interface.

Login: the user enters the information, so use the doGet method

@ WebServlet (name = "ServletLogin") public class ServletLogin extends HttpServlet {public void init () throws ServletException {} public void doGet (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {boolean bounded false; userlogin MyPOJO=new userlogin (); / / the object myPOJO of the new MyPOJO class / / gets the parameter String id=request.getParameter ("id") contained in the form in the JSP file according to the tag name; String password=request.getParameter ("password") String result = ""; b=MyPOJO.isuserlogin (id,password); / / use the model to validate the account and password and return an object of type boolean PrintWriter out = response.getWriter (); if (b) {/ / if the verification result is true, jump to the login success page out.println ("success"); result = "success" / / Cookie Cookie username= new Cookie ("username", id); / / set the path, that is, the cookie can be accessed under the project. If you do not set the path, only the cookie path and its subpaths can access username.setPath ("/"); username.setMaxAge (60 / 60); response.addCookie (username) Response.sendRedirect ("index.jsp");} else {/ / if the verification result is false, jump to the login failure page out.println ("fail"); result = "fail"; response.sendRedirect ("JSP/LoginFailed.jsp");} out.write (result); out.flush (); out.close () System.out.println (result);}

Registration: using the doPost method

@ WebServlet (name = "ServletRegister") public class ServletRegister extends HttpServlet {protected void doPost (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {boolean b = false; register myPOJO=new register (); String id=request.getParameter ("username"); String password=request.getParameter ("password1"); String email = request.getParameter ("email"); b=myPOJO.userregister (id,password,email) If (b) {response.sendRedirect ("login.jsp");} else {response.sendRedirect ("register.jsp");}

5. Match servlet and url-pattern in web.xml

ServletLogin service.ServletLogin ServletLogin / login.do ServletRegister service.ServletRegister ServletRegister / register.do

6. Test run

Add a user message to the server-side mysql database:

Insert into ulogin values ('test1','123',null)

Enter this information on the web page:

Click to log in: login is successful

Registration: enter information in the registration box:

Find the user information in the database after submission:

Note: two jar packages jsp-api.jar and servlet-api.jar should be imported into the project.

At this point, I believe you have a deeper understanding of "how to achieve login and registration functions in java+mysql". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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