MyEclipse 生成注册和登陆时经常见到的随机图片
工程名：IdentifyServlet
Servlet名：IdentityServlet 和 ComeOn.html(这个是图片程序的入口)
IdentityServlet.java:
package com.helloweenvsfei.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.awt.color.*;
import java.awt.font.*;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public class IdentityServlet extends HttpServlet {
public static final char[] CHARS = { '2', '3', '4', '5', '6', '7', '8',
'9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L',
'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
public static Random random = new Random();
public static String getRandomString() {
StringBuffer buffer = new StringBuffer();
for (int i = 0; i < 6; i++) {
buffer.append(CHARS[random.nextInt(CHARS.length)]);
}
return buffer.toString();
}
public static Color getRandomColor() {
return new Color(random.nextInt(255), random.nextInt(255), random
.nextInt(255));
}
public static Color getReverseColor(Color c) {
return new Color(255 - c.getRed(), 255 - c.getGreen(), 255 - c
.getBlue());
}
/**
* Constructor of the object.
*/
public IdentityServlet() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
/**
* 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 {
response.setContentType("image/jpeg");
String randomString = getRandomString();
request.getSession(true).setAttribute("randomString", randomString);
int width = 100;
int height = 30;
Color color = getRandomColor();
Color reverse = getReverseColor(color);
BufferedImage bi = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
g.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 16));
g.setColor(color);
g.fillRect(0, 0, width, height);
g.setColor(reverse);
g.drawString(randomString, 18, 20);
for (int i = 0, n = random.nextInt(60); i < n; i++) {
g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1);
}
ServletOutputStream out = response.getOutputStream();
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(bi);
out.flush();
/*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 GET method");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();*/
}
/**
* 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 occurs
*/
public void init() throws ServletException {
// Put your code here
}
}
Web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>IdentityServlet</servlet-name>
<servlet-class>com.helloweenvsfei.servlet.IdentityServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>IdentityServlet</servlet-name>
<url-pattern>/servlet/IdentityServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
ComeOn.html:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<script>
function reloadImage() {
document.getElementById('btn').disabled = true;
document.getElementById('identity').src = 'http://localhost:8080/IdentityServlet/servlet/IdentityServlet?ts=' + new Date()
.getTime();
}
</script>
<img src="http://localhost:8080/IdentityServlet/servlet/IdentityServlet" id="identity"
onload="btn.disabled = false; " />
<input type=button value="换个图片" onclick="reloadImage()" id="btn" />
</body>
</html>