Java Verification Code implementation

The role of verification code is not much to say directly to see the effect of it

Package Com.shangdi.naxincameraserver.webpage;import Java.awt.color;import Java.awt.font;import java.awt.Graphics; Import Java.awt.graphics2d;import java.awt.image.bufferedimage;import java.io.ioexception;import java.util.Random; Import Javax.imageio.imageio;import Javax.servlet.http.httpservletrequest;import Javax.servlet.http.httpservletresponse;import Javax.servlet.http.httpsession;import Org.springframework.stereotype.controller;import org.springframework.web.bind.annotation.requestmapping;@ Controller@requestmapping ("/verfycode") public class Verifycode {public static final int width = 165;//The width of the generated picture public STA Tic Final int height = 36;//the height of the resulting picture @requestmapping (value= "/code") public void Getverifycode (HttpServletRequest request , httpservletresponse response) {//Set the response header to notify the browser to open the Response.setcontenttype ("Image/jpeg") as a picture;// Equivalent to Response.setheader ("Content-type",//"image/jpeg");//Set Response header control browser do not cache Response.setdateheader ("Expries",-1); Response.setheader ("Cache-control", "No-cache"); response.seTheader ("Pragma", "No-cache");//1. Create a picture in memory bufferedimage image = New BufferedImage (WIDTH, Height,bufferedimage.type _INT_RGB);//2. The virtual brush gets the picture graphics G = image.getgraphics ();//3. Set the background color of the picture setbackground (g);//4. Set the border of the picture SetBorder (g);//5. Draw an interference line drawrandomline (g) on the picture;//6. Write the random number on the picture string random = Drawrandomnum ((graphics2d) g);//Generate a combination of numbers and letters with the CAPTCHA image//7. The random number exists in the session HttpSession Session=request.getsession (TRUE); Session.setattribute ("Checkcode", random);// Within two minutes of expiration session.setmaxinactiveinterval (2*60);//8. Write the picture to the browser try {imageio.write (image, "jpg", Response.getoutputstream ());} catch (IOException e) {e.printstacktrace ();}}  /** * Set the background color of the picture * * @param g */private void SetBackground (Graphics g) {//Set color G.setcolor (color.white);//Fill area g.fillrect (0, 0, WIDTH, HEIGHT);}  /** * Set the border of the picture * * @param g */private void SetBorder (Graphics g) {//Set Border color G.setcolor (color.white);//Border area g.drawrect (1, 1, WIDTH-2, HEIGHT-2);} /** * Draw random lines on the picture * * @param g */private void Drawrandomline (Graphics g) {//Set color//g.setcolor (color.greEN); Random r=new random ();//Set the number of lines and draw lines for (int i = 0; i <; i++) {int x1 = r.nextint (WIDTH); int y1 = R.nextint (HEIGHT); T x2 = r.nextint (WIDTH), int y2 = R.nextint (HEIGHT), G.drawline (x1, y1, x2, y2),//Set interference line color, colour color = new Color (+ R.next Int (R.nextint), + + (+), + R.nextint (()); G.setcolor (color);}} /** * Draw Random characters * * @param g */private String drawrandomnum (graphics2d g) {//Set color G.setcolor (color.red);//Set Font G.setfont (new Font ("Arial", Font.Bold, 30));//combination of numbers and letters string basenumletter = " Aa0bb1ccdd3eeff5gg6hhjjkkll7mmn9noopp8qqrrss2ttuuvv4wwxxyyzz "; return Createrandomchar (G, baseNumLetter);} /** * Create random characters * * @param g * @param Basechar * @return Random characters */private string Createrandomchar (graphics2d g, String Basecha R) {StringBuffer sb = new StringBuffer (); Random r=new random (); int x = 5; String ch = "";//control word for (int i = 0; I < 4; i++) {//Set font rotation angle int degree = r.nextint ()% 30;ch = Basechar.charat (new random (). Nextint (Basechar.length ())) + "";//Set random number Colour color = new ColoR (+ r.nextint), + r.nextint (+), + r.nextint (210)); G.setcolor (color); Sb.append (CH);//Positive angle g.rotate (degree * math.pi/180, x, +); g.drawstring (CH, x, 20);//Reverse Angle g.rotate (-degree * MATH.PI/1 x + + 30;} return sb.tostring ();}}

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verfycode/code" id= "Valcode" onclick= "Refresh (this, ' <%=basepath%>verfycode/ Code ') "><script type=" Text/javascript ">function Refresh (Thisobj,path) {//math.random (); Prevent client browsers from using cache thisobj.src=path+ "?" +math.random ();} </script>

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Java Verification Code implementation