Package Org.servlet.demo;
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.nio.charset.Charset;
Import Java.util.Random;
Import Javax.imageio.ImageIO;
Import javax.servlet.ServletException;
Import Javax.servlet.http.HttpServlet;
Import Javax.servlet.http.HttpServletRequest;
Import Javax.servlet.http.HttpServletResponse;
public class Drawimageservlet extends HttpServlet {
/**
* In the user login interface, one will require digital random verification to prevent other people from malicious attacks
*
*/
Define the width and height of the picture
public static final int WIDTH = 200;
public static final int HEIGHT = 50;
protected void Doget (HttpServletRequest req, HttpServletResponse resp)
Throws Servletexception, IOException {
Create a picture Bufferedimage.type_int_rgb set the picture type
BufferedImage image = New BufferedImage (WIDTH, HEIGHT,
BUFFEREDIMAGE.TYPE_INT_RGB);
Get the paintbrush of the picture
Graphics g = image.getgraphics ();
Set Picture background color
SetBackground (g);
Set the border of a picture
SetBorder (g);
Sketch the interfering lines on the picture
Drawrandomline (g);
Write random numbers on a picture
Writerandomnum (g);
Tell the browser to write the type
Resp.setcontenttype ("Image/jpeg");
Write a picture to the browser
Imageio.write (image, "JPG", Resp.getoutputstream ());
Head control do not let the browser cache
Resp.setdateheader ("Expries",-1);
Resp.setheader ("Cache-control", "No-cache");
Resp.setheader ("Pragma", "No-cache");
}
private void Writerandomnum (graphics graphics) {
/** [\u4e00-\u9fa5] is the interval regular expression of Chinese characters
\\u is represented as being present in the Uncode Code table
It means that Chinese characters are in the \u (uncode) code table between 4e00 and 9fa5 */
String base=
"\u7684\u4e00\u4e86\u662f\u6211\u4e0d\u5728\u4eba\u4eec\u6709\u6765\u4ed6\u8fd9\u4e0a\u7740\u4e2a\u5730\u5230\ U5927\u91cc\u8bf4\u5c31\u53bb\u5b50\u5f97 "+
"\u4e5f\u548c\u90a3\u8981\u4e0b\u770b\u5929\u65f6\u8fc7\u51fa\u5c0f\u4e48\u8d77\u4f60\u90fd\u628a\u597d\u8fd8\ U591a\u6ca1\u4e3a\u53c8\u53ef\u5bb6\u5b66 "+
"\u53ea\u4ee5\u4e3b\u4f1a\u6837\u5e74\u60f3\u751f\u540c\u8001\u4e2d\u5341\u4ece\u81ea\u9762\u524d\u5934\u9053\ U5b83\u540e\u7136\u8d70\u5f88\u50cf\u89c1 "+
"\u4e24\u7528\u5979\u56fd\u52a8\u8fdb\u6210\u56de\u4ec0\u8fb9\u4f5c\u5bf9\u5f00\u800c\u5df1\u4e9b\u73b0\u5c71\ u6c11\u5019\u7ecf\u53d1\u5de5\u5411\u4e8b "+
"\u547d\u7ed9\u957f\u6c34\u51e0\u4e49\u4e09\u58f0\u4e8e\u9ad8\u624b\u77e5\u7406\u773c\u5fd7\u70b9\u5fc3\u6218\ u4e8c\u95ee\u4f46\u8eab\u65b9\u5b9e "+
"\u5403\u505a\u53eb\u5f53\u4f4f\u542c\u9769\u6253\u5462\u771f\u5168\u624d\u56db\u5df2\u6240\u654c\u4e4b\u6700\ u5149\u4ea7\u60c5\u8def\u5206\u603b\u6761 "+
"\u767d\u8bdd\u4e1c\u5e2d\u6b21\u4eb2\u5982\u88ab\u82b1\u53e3\u653e\u513f\u5e38\u6c14\u4e94\u7b2c\u4f7f\u5199\ u519b\u5427\u6587\u8fd0\u518d\u679c "+
"\u600e\u5b9a\u8bb8\u5feb\u660e\u884c\u56e0\u522b\u98de\u5916\u6811\u7269\u6d3b\u90e8\u95e8\u65e0\u5f80\u8239\ u671b\u65b0\u5e26\u961f\u5148\u529b "+
"\u5b8c\u5374\u7ad9\u4ee3\u5458\u673a\u66f4\u4e5d\u60a8\u6bcf\u98ce\u7ea7\u8ddf\u7b11\u554a\u5b69\u4e07\u5c11\ u76f4\u610f\u591c\u6bd4\u9636 "+
"\u8fde\u8f66\u91cd\u4fbf\u6597\u9a6c\u54ea\u5316\u592a\u6307\u53d8\u793e\u4f3c\u58eb\u8005\u5e72\u77f3\u6ee1\ U65E5\U51B3\U767E\U539F\U62FF\U7FA4 "+
"\u7a76\u5404\u516d\u672c\u601d\u89e3\u7acb\u6cb3\u6751\u516b\u96be\u65e9\u8bba\u5417\u6839\u5171\u8ba9\u76f8\ u7814\u4eca\u5176\u4e66\u5750 "+
"\u63a5\u5e94\u5173\u4fe1\u89c9\u6b65\u53cd\u5904\u8bb0\u5c06\u5343\u627e\u4e89\u9886\u6216\u5e08\u7ed3\u5757\ u8dd1\u8c01\u8349\u8d8a\u5b57\u52a0\u811a "+
"\u51c6\u5f20\u56e2\u5c4b\u79bb\u8272\u8138\u7247\u79d1\u5012\u775b\u5229\u4e16\u521a\u4e14\u7531\u9001\u5207\ U661F\U5BFC\U665A\U8868\U591F\U6574\U8BA4 "+
"\u544a\u754c\u62c9\u540d\u5440\u571f\u6e05\u9633\u7167\u529e\u53f2\u6539\u5386\u8f6c\u753b\u9020\u5634\u6b64\ u6cbb\u5317\u5fc5\u670d "+
"\u96e8\u7a7f\u5185\u8bc6\u9a8c\u4f20\u4e1a\u83dc\u722c\u7761\u5174\u5f62\u91cf\u54b1\u89c2\u82e6\u4f53\u4f17\ u901a\u51b2\u5408\u7834 "+
"\u53cb\u5ea6\u672f\u996d\u516c\u65c1\u623f\u6781\u5357\u67aa\u8bfb\u6c99\u5c81\u7ebf\u91ce\u575a\u7a7a\u6536\ U7b97\u81f3\u653f\u57ce "+
"\u52b3\u843d\u94b1\u7279\u56f4\u5f1f\u80dc\u6559\u70ed\u5c55\u5305\u6b4c\u7c7b\u6e10\u5f3a\u6570\u4e61\u547c\ U6027\u97f3\u7b54\u54e5 "+
"\u9645\u65e7\u795e\u5ea7\u7ae0\u5e2e\u5566\u53d7\u7cfb\u4ee4\u8df3\u975e\u4f55\u725b\u53d6\u5165\u5cb8\u6562\ U6389\u5ffd\u79cd\u88c5 "+
"\u7d27\u7231\u7b49\u4e60\u9635\u6015\u6708\u9752\u534a\u706b\u6cd5\u9898\u5efa\u8d76\u4f4d\u5531\u6d77\u4e03\ u5973\u4efb\u4ef6\u611f "+
"\U9876\U6025\U6797\U505C\U606F\U53E5\U533A\U8863\U822C\U62A5\U53F6\U538B\U6162\U53D4\U80CC\U7EC6" +
"\u54cd\u96ea\u6d41\u672a\u573a\u8be5\u5e76\u5e95\u6df1\u523b\u5e73\u4f1f\u5fd9\u63d0\u786e\u8fd1\u4eae\u8f7b\ U8bb2\u519c\u53e4\u9ed1 ";
Graphics2D inside the method can set the rotational radian
Graphics2D g= (graphics2d) graphics;
Set Font Color
G.setcolor (color.red);
Set font style
G.setfont (New Font ("Arial", Font.Bold, 30));
Write 4 man
int x=10;
for (int i = 0; i < 4; i++) {
Set the radian of a font
Double D=new Random (). Nextint ()%30;
String target=string.valueof (Base.charat (New Random (). Nextint (Base.length ()));
Set the font radian
G.rotate (d*math.pi/180, X, 35);
Font is written in the rectangle need to consider the font space and the coordinates of the font, the Y-mark is unchanged
g.DrawString (target, X, 35);
Turn the font radian back, or the next word will spin out
G.rotate (-d*math.pi/180, X, 35);
The font size is 20, no interval 10 is written to a
x+=45;
}
}
Sketch the interfering lines on the picture
private void Drawrandomline (Graphics g) {
G.setcolor (Color.green);//Set the color of the interfering line
Sketch 10 lines of interference
for (int i = 0; I <10; i++) {
Sketch the initial coordinate position of the line, whose position must be within the size of the picture
int x1= new Random (). Nextint (WIDTH);
int y1= new Random (). Nextint (HEIGHT);
End coordinates
int x2= new Random (). Nextint (WIDTH);
int y2= new Random (). Nextint (HEIGHT);
G.drawline (x1, y1, x2, y2);
}
}
Set Border color
private void SetBorder (Graphics g) {
G.setcolor (Color.Blue);
G.drawrect (1, 1, WIDTH-2, HEIGHT-2);
}
Set the background color of a picture
private void SetBackground (Graphics g) {
G.setcolor (Color.White);//White
G.fillrect (0, 0, WIDTH, HEIGHT);//fill in the picture color
}
@Override
protected void DoPost (HttpServletRequest req, HttpServletResponse resp)
Throws Servletexception, IOException {
Doget (req, resp);
}
}
----------------------Effect---
Register a picture verification code in Java
