前言
本文介紹的imagecode方法是一個生成圖形驗證碼的請求，checkcode方法實現了對這個圖形驗證碼的驗證。從驗證碼的生成到驗證的過程中，驗證碼是通過Session來保存的，并且設定一個驗證碼的最長有效時間為5分鐘。驗證碼的生成規則是從0~9的數字中，隨機產生一個4位數，并增加一些干擾元素，最終組合成為一個圖形輸出
1、驗證碼生成類
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
import java.awt.*;import java.awt.image.BufferedImage;import java.io.OutputStream;import java.util.HashMap;import java.util.Map;import java.util.Random;public class ImageCode { private static char mapTable[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'}; public static Map<String, Object> getImageCode(int width, int height, OutputStream os) { Map<String,Object> returnMap = new HashMap<String, Object>(); if (width <= 0) width = 60; if (height <= 0) height = 20; BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 獲取圖形上下文 Graphics g = image.getGraphics(); //生成隨機類 Random random = new Random(); // 設定背景色 g.setColor(getRandColor(200, 250)); g.fillRect(0, 0, width, height); //設定字體 g.setFont(new Font("Times New Roman", Font.PLAIN, 18)); // 隨機產生168條干擾線，使圖象中的認證碼不易被其它程序探測到 g.setColor(getRandColor(160, 200)); for (int i = 0; i < 168; i++) { int x = random.nextInt(width); int y = random.nextInt(height); int xl = random.nextInt(12); int yl = random.nextInt(12); g.drawLine(x, y, x + xl, y + yl); } //取隨機產生的碼 String strEnsure = ""; //4代表4位驗證碼,如果要生成更多位的認證碼,則加大數值 for (int i = 0; i < 4; ++i) { strEnsure += mapTable[(int) (mapTable.length * Math.random())]; // 將認證碼顯示到圖象中 g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110))); //直接生成 String str = strEnsure.substring(i, i + 1); g.drawString(str, 13 * i + 6, 16); } // 釋放圖形上下文 g.dispose(); returnMap.put("image",image); returnMap.put("strEnsure",strEnsure); return returnMap; } //給定范圍獲得隨機顏色 static Color getRandColor(int fc, int bc) { Random random = new Random(); if (fc > 255) fc = 255; if (bc > 255) bc = 255; int r = fc + random.nextInt(bc - fc); int g = fc + random.nextInt(bc - fc); int b = fc + random.nextInt(bc - fc); return new Color(r, g, b); }} |
2、獲取驗證碼API
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
|
@RequestMapping(value = "/images/imagecode")public String imagecode(HttpServletRequest request, HttpServletResponse response) throws Exception { OutputStream os = response.getOutputStream(); Map<String,Object> map = ImageCode.getImageCode(60, 20, os); String simpleCaptcha = "simpleCaptcha"; request.getSession().setAttribute(simpleCaptcha, map.get("strEnsure").toString().toLowerCase()); request.getSession().setAttribute("codeTime",new Date().getTime()); try { ImageIO.write((BufferedImage) map.get("image"), "JPEG", os); } catch (IOException e) { return ""; } return null;} |
3、驗證驗證碼API
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
|
@RequestMapping(value = "/checkcode")@ResponseBodypublic String checkcode(HttpServletRequest request, HttpSession session) throws Exception { String checkCode = request.getParameter("checkCode"); Object cko = session.getAttribute("simpleCaptcha") ; //驗證碼對象 if(cko == null){ request.setAttribute("errorMsg", "驗證碼已失效，請重新輸入！"); return "驗證碼已失效，請重新輸入！"; } String captcha = cko.toString(); Date now = new Date(); Long codeTime = Long.valueOf(session.getAttribute("codeTime")+""); if(StringUtils.isEmpty(checkCode) || captcha == null || !(checkCode.equalsIgnoreCase(captcha))) { request.setAttribute("errorMsg", "驗證碼錯誤！"); return "驗證碼錯誤！"; } else if ((now.getTime()-codeTime)/1000/60>5) { //驗證碼有效時長為5分鐘 request.setAttribute("errorMsg", "驗證碼已失效，請重新輸入！"); return "驗證碼已失效，請重新輸入！"; }else { session.removeAttribute("simpleCaptcha"); return "1"; }} |
總結
以上就是這篇文章的全部內容了，希望本文的內容對大家的學習或者工作能帶來一定的幫助，如果有疑問大家可以留言交流，謝謝大家對服務器之家的支持。
原文鏈接：http://www.jianshu.com/p/29f005992527
