運用Struts2.0實現頁面中的驗證碼

<1>畫驗證碼核心類ValidateCodeAction

1. package com.tarena.common.action;
3. import java.awt.*;
4. import java.awt.image.BufferedImage;
5. import java.io.ByteArrayInputStream;
6. import java.io.ByteArrayOutputStream;
7. import java.util.Random;
8. import javax.imageio.ImageIO;
9. import javax.imageio.stream.ImageOutputStream;
10. import com.opensymphony.xwork2.ActionContext;
11. /**
12. * 網頁中驗證碼的實現
13. * @author JimmyZhang
14. * @since 2012.5.10
15. *
16. */
17. public class ValidateCodeAction {
19. private ByteArrayInputStream inputStream;
20. //默認的執行方法
21. public String execute() throws Exception{
22. Random r = new Random();
23. //BufferedImage相當與緩存在內存中的圖像
24. BufferedImage image =
25. new BufferedImage(60,//繪圖區域的長度
26. 20,//繪圖區域的高度
27. BufferedImage.TYPE_INT_RGB);
28. //獲取繪圖工具Graphiscs
29. Graphics g = image.getGraphics();
30. //設置繪圖顏色
31. g.setColor(new Color(r.nextInt(255),
32. r.nextInt(255),
33. r.nextInt(255)));
34. //從原點(0,0)填充繪圖區域
35. g.fillRect(0, 0, 60, 20);
36. //生成一個隨機的字符串（5位數字）
37. String number = String.valueOf(r.nextInt(99999));
38. //將number繪制在image中
39. g.setColor(new Color(0,0,0));
40. g.drawString(number, 5, 15);
41. //將number保存在Session中
42. ActionContext ac = ActionContext.getContext();
43. ac.getSession().put("vcode", number);
44. //畫干擾線
45. for(int i=0; i<3;i++){
46. drawLine(g,r);
47. }
48. //寫入到字節輸出流中
49. ByteArrayOutputStream output = new ByteArrayOutputStream();
50. ImageOutputStream imageOutput =
51. ImageIO.createImageOutputStream(output);
52. //將圖像image寫入到imageOutput中
53. ImageIO.write(image, "jpeg", imageOutput);
54. //根據output構建inputStream
55. inputStream = new ByteArrayInputStream(
56. output.toByteArray());
57. //對象之間的轉換--image-->ByteArrayOutStream-->ByteArrayInputStream
58. return "success";
59. }
61. //輔助方法，用於繪制一條干擾線
62. private void drawLine(Graphics g,Random r){
63. g.setColor(new Color(r.nextInt(255),
64. r.nextInt(255),
65. r.nextInt(255)));
66. //drawLine(x1,y1,x2,y2)
67. g.drawLine(
68. r.nextInt(60), r.nextInt(20),
69. r.nextInt(60), r.nextInt(20));
70. }
72. public ByteArrayInputStream getInputStream() {
73. return inputStream;
74. }
76. public void setInputStream(ByteArrayInputStream inputStream) {
77. this.inputStream = inputStream;
78. }
80. }