JSP adds a verification code to implement the login function, jsp implements the login verification code

JSP adds a verification code to implement the login function, jsp implements the login verification code

Jsp login verification, webpage login verification with verification code, login function to add Verification Code

Part_1: class used to generate a verification code image: VerificationCode. Java

Package cn. mike. javase. test; import java. awt. color; import java. awt. font; import java. awt. graphics2D; import java. awt. image. bufferedImage; import java. io. file; import java. io. fileNotFoundException; import java. io. fileOutputStream; import java. io. IOException; import java. io. outputStream; import java. util. random; import javax. imageio. imageIO; import org. junit. test;/*** @ author: Administrator * @ fu Nction: This is the class used to test the randomly generated Verification Code image; */public class VerificationCode {/*** unit test, try to automatically generate a verification code image * // this function is used for unit testing. Here, it cannot be called outside the private domain; /* @ Test * // * public */private void test_fun () {VerificationCode vc = new VerificationCode (); BufferedImage image = vc. getImage (); try {// generate the verification code image and save it to the specified path VerificationCode. output (image, new FileOutputStream (new File (". \ image \ vcode_2.jpg ");} catch (FileNotFou NdException e) {e. printStackTrace ();} // outputs randomly generated text content to the console for System verification. out. println (vc. getText ();} private int w = 70; // wide private int h = 35; // high private String text; // text content (Verification code String) private Random r = new Random (); private String [] fontNames = {"", "文 ", ""," ", "_ GB2312"}; // random character sets do not include 0, o, 1, and l, because these cannot distinguish private String codes = "23456789 abcdefghijkmnopqrstuvwxyzabcdefghilmjknopqrs TUVWXYXZ "; // background Color of the Verification Code image: White private Color bgColor = new Color (255,255,255);/*** return a verification code image buffer object: BufferedImage */public BufferedImage getImage () {BufferedImage image = createImage (); // obtain the drawing environment (paint brush tool) Graphics2D g2 = (Graphics2D) image. getGraphics (); // sb: used to save the text content of the verification code string StringBuilder sb = new StringBuilder (); for (int I = 0; I <4; ++ I) {// Four Characters String s = randomChar () + ""; sb. append (s ); Float x = I * 1.0F * w/4; g2.setFont (randomFont (); g2.setColor (randomColor (); g2.drawString (s, x, h-5 );} this. text = sb. toString (); // record the text content of the Verification Code drawLine (image); // draw the interference line return image ;} /*** @ return get verification code text content */public String getText () {return text ;} /*** @ param image * @ param out * writes the text to the specified output stream. For example, the storage path */public static void output (BufferedImage image, OutputStream out) specified by FileOutputStream in this test {try {ImageIO. write (image, "jpeg", out);} catch (IOException e) {e. printStackTrace () ;}} private void drawLine (BufferedImage image) {Graphics2D g2 = (Graphics2D) image. getGraphics (); for (int I = 0; I <3; ++ I) {// draw 3 interference lines int x1 = r. nextInt (w); int y1 = r. nextInt (h); int x2 = r. nextInt (w); int y2 = r. nextInt (h); g2.setColor (Color. BLUE); g2.drawLine (x1, y1, x2, y2) ;}} private Color randomColor () {int red = r. nextInt (150); int green = r. nextInt (150); int blue = r. nextInt (150); return new Color (red, green, blue);} private Font randomFont () {int index = r. nextInt (fontNames. length); String fontName = fontNames [index]; int style = r. nextInt (4); int size = r. nextInt (5) + 24; return new Font (fontName, style, size);} private char randomChar () {int index = r. nextInt (codes. length (); return codes. charAt (index);} private BufferedImage createImage () {BufferedImage image = new BufferedImage (w, h, BufferedImage. TYPE_INT_RGB); Graphics2D g2 = (Graphics2D) image. getGraphics (); g2.setColor (this. bgColor); g2.fillRect (0, 0, w, h); return image ;}}

Part_2: logon interface: Login. jsp

<% @ Page language = "java" import = "java. util. * "pageEncoding =" UTF-8 "%> <% String path = request. getContextPath (); String basePath = request. getScheme () + ": //" + request. getServerName () + ":" + request. getServerPort () + path + "/"; %> <! Doctype html public "-// W3C // dtd html 4.01 Transitional // EN"> 
Part_3: servlet for processing login verification: LoginVerificationServlet. java
Package cn. mike. servlet. test_1212; import java. awt. image. bufferedImage; import java. io. IOException; import javax. servlet. servletException; import javax. servlet. http. httpServlet; import javax. servlet. http. httpServletRequest; import javax. servlet. http. httpServletResponse; import cn. mike. javase. test. verificationCode; public class GetVerificationCodeServlet extends HttpServlet {private static final long serialVersionUID =-response; public void doGet (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// 1. create a VerificationCode class; VerificationCode vc = new VerificationCode (); // 2. obtain the BufferedImage object from the VerificationCode class; BufferedImage bufImage = vc. getImage (); // 3. obtain the text content in the verification code and put it in the session domain for verification. String code_text = vc. getText (); request. getSession (). setAttribute ("code_text", code_text); // 4. output the generated image to the client browser VerificationCode. output (bufImage, response. getOutputStream ();} // end method-doGet public void doPost (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// do same as GET-method: doGet (request, request, response);} // end method-doPost}
Part_4: successful login after the prompt interface 1: success-page-1.jsp
<% @ Page language = "java" import = "java. util. * "pageEncoding =" UTF-8 "%> <% String path = request. getContextPath (); String basePath = request. getScheme () + ": //" + request. getServerName () + ":" + request. getServerPort () + path + "/"; %> <! Doctype html public "-// W3C // dtd html 4.01 Transitional // EN"> 
Part_5: successful login after the prompt interface 1: success-page-2.jsp
<% @ Page language = "java" import = "java. util. date "pageEncoding =" UTF-8 "%> <% @ page language =" java "import =" java. text. simpleDateFormat "%> <% String path = request. getContextPath (); String basePath = request. getScheme () + ": //" + request. getServerName () + ":" + request. getServerPort () + path + "/"; %> <! Doctype html public "-// W3C // dtd html 4.01 Transitional // EN"> 
The above section describes how to add a verification code for JSP login. I hope it will help you. If you have any questions, please leave a message and I will reply to you in a timely manner. Thank you very much for your support for the help House website!