1 package util;
2
3 Import javax.imageio.imageio;
4 Import Javax.Servlet.ServletException;
5 Import javax.servlet.http.httpservlet;
6 Import Javax.Servlet.http.httpservletRequest;
7 Import javax.servlet.http.httpservletResponse;
8 Import java.awt. *;
9 Import Java.awt.Image.BufferedImage;
10 Import java.io.ioException;
11 Import Java.util.random;
12
13
14 / **
15 * Description:
16 *
17 * @Author $ Author $
18 * @version $ revision $
19 * /
20 Public Class Piccheckcode Extends httpservlet {
twenty one
22 private font mfont = new font ("arial black", font.plain, 15); // set font
23 private int lineWidth = 2; // Distress line length = 1.414 * LineWidth
24 private int width = 60; // Define graphical size
25 private int Height = 20; // Define graphical size
26 private int count = 200;
27
28 / **
29 * Description:
30 *
31 * @Param FC description:
32 * @Param BC Description:
33 *
34 * @return description:
35 * /
36 Private Color GetrandColor (int FC, int BC) {// get a given range random color
37
38 Random Random = new random ();
39
40 IF (fc> 255) {
41
42 fc = 255;
43}
44
45 IF (BC> 255) {
46
47 bc = 255;
48}
49
50 int R = fc random.nextINT (BC - FC);
51 INT g = fc random.nextint (BC - FC);
52 int b = fc random.nextint (BC - FC);
53
54 RETURN New Color (R, G, B);
55}
56
57 // Processing POST
58 Public Void Dopost (httpservletRequest Request, httpservletResponse response)
59 THROWS servletexception, ioException {
60
61 Doget (Request, Response); 62}
63
64 / **
65 * Description:
66 *
67 * @Param Request Description:
68 * @Param Response Description:
69 *
70 * @Throws ServletException Description:
71 * @Throws IOException Description:
72 * /
73 public void doget (httpservletRequest Request, HTTPSERVLETRESPONSE RESPONSE)
74 THROWS servletexception, ioException {
75
76 //Response.reset ();
77 // Settings page does not cache
78 Response.setheader ("Pragma", "No-Cache");
79 Response.setheader ("Cache-Control", "No-Cache");
80 response.SetDateHeader ("Expires", 0);
81 Response.setContentType ("Image / GIF");
82
83 // Create image in memory
84 BufferedImage Image = New BufferedImage (Width, Height,
85 BufferedImage.Type_Int_RGB);
86
87 // Get the graphical context
88 graphics2d g = (graphics2d) image.getgraphics ();
89
90 // Generate random class
91 Random Random = new random ();
92
93 // Setting the background color
94 G.SetColor (Getrandcolor (200, 250)); // --- 1
95
96 g.fillRect (0, 0, width, height);
97
98 // Setting the font
99 G.SetFont (mfont);
100
101 // Sea Box
102 G.SetColor (GetrandColor (0, 20)); // --- 2
103 g.drawRect (0, 0, Width - 1, HEIGHT - 1);
104
105 // randomly generates the interference line, causing the authentication code in the image to be probed by other programs
106 for (int i = 0; i 107 108 G.SetColor (GetrandColor (150, 200)); // --- 3 109 110 int x = random.nextint (width - linewidth - 1) 1; // guaranteed to draw within the border 111 int y = random.nextint (HEIGHT - LINEWIDTH - 1) 1; 112 INT XL = Random.Nextint (LineWIDTH); 113 int yl = random.nextint (LINEWIDTH); 114 g.drawline (X, Y, X XL, Y YL); 115} 116 117 // Take the randomly generated authentication code (4 digits) 118 string srand = "" 119 120 for (int i = 0; i <4; i ) { 121 122 string rand = string.valueof (random.nextint (10)); 123 SRAND = RAND; 124 125 // Display the authentication code to the image, the color of the call function is the same, may be because the seed is too close, so only directly generate 126 G.SetColor (New Color (20 random.nextint (130), 127 20 random.nextint (130), 20 random.nextint (130))); // - 4--50-100 128 129 g.drawstring (rand, (13 * i) 6, 16); 130 131 132} 133 134 // Deposit the authentication code into the session 135 Request.getSession () .SetAttribute ("getimg", srand; 136 137 // Image takes effect 138 g.dispose (); 139 140 // Output image to page 141 Imageio.write (Image, "PNG", response.getOutputStream ()); 142} 143} - How to use it in jsp? Assume the servlet name is piccheckcodeservlet
