java 生成验证码的servlet类

1. 生成验证码的servlet类

Java代码

1. import java.awt.Color;
2. import java.awt.Font;
3. import java.awt.Graphics;
4. import java.awt.image.BufferedImage;
5. import java.io.IOException;
6. import java.io.OutputStream;
7. import java.io.PrintWriter;
8. import java.util.Random;
10. import javax.imageio.ImageIO;
11. import javax.servlet.ServletException;
12. import javax.servlet.http.HttpServlet;
13. import javax.servlet.http.HttpServletRequest;
14. import javax.servlet.http.HttpServletResponse;
15. import javax.servlet.http.HttpSession;
17. import com.***.constant.Constant;
20. public class ImageValidate extends HttpServlet {
22. /**
23. *
24. */
25. private static final long serialVersionUID = 2198678289097775859L;
26. /**
27. * Constructor of the object.
28. */
29. public ImageValidate() {
30. super();
31. }
33. /**
34. * Destruction of the servlet. <br>
35. */
36. public void destroy() {
37. super.destroy(); // Just puts "destroy" string in log
38. // Put your code here
39. }
41. private String name;
42. /**
43. * The doGet method of the servlet. <br>
44. *
45. * This method is called when a form has its tag value method equals to get.
46. *
47. * @param request
48. * the request send by the client to the server
49. * @param response
50. * the response send by the server to the client
51. * @throws ServletException
52. * if an error occurred
53. * @throws IOException
54. * if an error occurred
55. */
56. public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException,
57. IOException {
59. OutputStream outputStream = null;
61. try {
62. outputStream = response.getOutputStream();
63. // 在内存中创建图象
64. int width = 60, height = 20;
65. BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
66. // 获取图形上下文
67. Graphics g = image.getGraphics();
68. // 生成随机类
69. Random random = new Random();
70. // 设定背景色
71. g.setColor(getRandColor(200, 250));
72. g.fillRect(0, 0, width, height);
73. // 设定字体
74. g.setFont(new Font("Times New Roman", Font.CENTER_BASELINE, 18));
75. // 画边框
76. // g.setColor(new Color());
77. // g.drawRect(0,0,width-1,height-1);
78. // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
79. g.setColor(getRandColor(160, 200));
80. for (int i = 0; i < 40; i++) {
81. int x = random.nextInt(width);
82. int y = random.nextInt(height);
83. int xl = random.nextInt(12);
84. int yl = random.nextInt(12);
85. g.drawLine(x, y, x + xl, y + yl);
86. }
87. // 取随机产生的认证码(4位数字)
88. String sRand = "";
89. for (int i = 0; i < 4; i++) {
90. String rand = String.valueOf(random.nextInt(10));
91. sRand += rand;
92. // 将认证码显示到图象中
93. g
94. .setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random
95. .nextInt(110)));// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
96. g.drawString(rand, 13 * i + 6, 16);
97. }
98. // 将认证码存入SESSION
99. HttpSession session=request.getSession();
100. session.setAttribute(Constant.LOGIN_VALIDATE_IMAGE, sRand);
101. // 图象生效
102. g.dispose();
103. // 输出图象到页面
104. ImageIO.write(image, "JPEG",outputStream);
105. outputStream.flush();
106. } catch (Exception e) {
107. e.printStackTrace();
108. }finally{
109. outputStream.close();
110. }
114. }
116. /**
117. * 给定范围获得随机颜色
118. *
119. * @param fc
120. * @param bc
121. * @return
122. */
123. private static Color getRandColor(int fc, int bc) {
124. Random random = new Random();
125. if (fc > 255)
126. fc = 255;
127. if (bc > 255)
128. bc = 255;
129. int r = fc + random.nextInt(bc - fc);
130. int g = fc + random.nextInt(bc - fc);
131. int b = fc + random.nextInt(bc - fc);
132. return new Color(r, g, b);
133. }
135. /**
136. * The doPost method of the servlet. <br>
137. *
138. * This method is called when a form has its tag value method equals to
139. * post.
140. *
141. * @param request
142. * the request send by the client to the server
143. * @param response
144. * the response send by the server to the client
145. * @throws ServletException
146. * if an error occurred
147. * @throws IOException
148. * if an error occurred
149. */
150. public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException,
151. IOException {
153. response.setContentType("text/html");
154. PrintWriter out = response.getWriter();
155. out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
156. out.println("<HTML>");
157. out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
158. out.println(" <BODY>");
159. out.print(" This is ");
160. out.print(this.getClass());
161. out.println(", using the POST method");
162. out.println(" </BODY>");
163. out.println("</HTML>");
164. out.flush();
165. out.close();
166. }
168. /**
169. * Initialization of the servlet. <br>
170. *
171. * @throws ServletException
172. * if an error occure
173. */
174. public void init() throws ServletException {
175. // Put your code here
176. }
178. }

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
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;
import javax.servlet.http.HttpSession;

import com.***.constant.Constant;


public class ImageValidate extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 2198678289097775859L;
	/**
	 * Constructor of the object.
	 */
	public ImageValidate() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	private String name;
	/**
	 * The doGet method of the servlet. <br>
	 * 
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request
	 *            the request send by the client to the server
	 * @param response
	 *            the response send by the server to the client
	 * @throws ServletException
	 *             if an error occurred
	 * @throws IOException
	 *             if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException,
			IOException {
		
	    OutputStream outputStream = null;
	    
	    try {
	    	outputStream =  response.getOutputStream();
	     // 在内存中创建图象
	        int width = 60, height = 20;
	        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
	        // 获取图形上下文
	        Graphics g = image.getGraphics();
	        // 生成随机类
	        Random random = new Random();
	        // 设定背景色
	        g.setColor(getRandColor(200, 250));
	        g.fillRect(0, 0, width, height);
	        // 设定字体
	        g.setFont(new Font("Times New Roman", Font.CENTER_BASELINE, 18));
	        // 画边框
	        // g.setColor(new Color());
	        // g.drawRect(0,0,width-1,height-1);
	        // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
	        g.setColor(getRandColor(160, 200));
	        for (int i = 0; i < 40; 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);
	        }
	        // 取随机产生的认证码(4位数字)
	        String sRand = "";
	        for (int i = 0; i < 4; i++) {
	            String rand = String.valueOf(random.nextInt(10));
	            sRand += rand;
	            // 将认证码显示到图象中
	            g
	                    .setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random
	                            .nextInt(110)));// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
	            g.drawString(rand, 13 * i + 6, 16);
	        }
	        // 将认证码存入SESSION
	        HttpSession session=request.getSession();
	        session.setAttribute(Constant.LOGIN_VALIDATE_IMAGE, sRand);
	        // 图象生效
	        g.dispose();
	        // 输出图象到页面
	        ImageIO.write(image, "JPEG",outputStream);
	        outputStream.flush();
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            outputStream.close();
        }
        
		

	}

	/**
	 * 给定范围获得随机颜色
	 * 
	 * @param fc
	 * @param bc
	 * @return
	 */
	private 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);
	}

	/**
	 * The doPost method of the servlet. <br>
	 * 
	 * This method is called when a form has its tag value method equals to
	 * post.
	 * 
	 * @param request
	 *            the request send by the client to the server
	 * @param response
	 *            the response send by the server to the client
	 * @throws ServletException
	 *             if an error occurred
	 * @throws IOException
	 *             if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException,
			IOException {

		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
		out.println("<HTML>");
		out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
		out.println("  <BODY>");
		out.print("    This is ");
		out.print(this.getClass());
		out.println(", using the POST method");
		out.println("  </BODY>");
		out.println("</HTML>");
		out.flush();
		out.close();
	}

	/**
	 * Initialization of the servlet. <br>
	 * 
	 * @throws ServletException
	 *             if an error occure
	 */
	public void init() throws ServletException {
		// Put your code here
	}

}