生成一个验证码图片，图片的参数可以手动设置
* 参数：
* count:验证码的字符个数
* width:验证码图片宽度
* height:验证码图片高度
* type:类型 0-纯数字 1-纯大写字母 2-数字和大学字母混合
* 功能：生成验证码图片，将验证码保存进session里
*/
import java.io.IOException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.*;
import java.util.*;
import javax.imageio.*;
public class ValidateCodeServlet extends HttpServlet {
private final int TYPE_NUMBER = 0;
private final int TYPE_LETTER = 1;
private final int TYPE_MULTIPLE = 2;
private int width;
private int height;
private int count;
private int type;
private String validate_code;
private Random random;
private Font font;
private int line;
public void init(ServletConfig config) throws ServletException {
super.init(config);
//TODO Method stub generated by Lomboz
width = 150;
height = 50;
count = 4;
type = TYPE_NUMBER;
random = new Random();
line = 200;
}
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);
response.setContentType("image.jpeg");
String reqCount = request.getParameter("count");
String reqWidth = request.getParameter("width");
String reqHeight = request.getParameter("height");
String reqType = request.getParameter("type");
if(reqCount!=null && reqCount!="")this.count = Integer.parseInt(reqCount);
if(reqWidth!=null && reqWidth!="")this.width = Integer.parseInt(reqWidth);
if(reqHeight!=null && reqHeight!="")this.height = Integer.parseInt(reqHeight);
if(reqType!=null && reqType!="")this.type = Integer.parseInt(reqType);
font = new Font("Courier New",Font.BOLD,width/count);
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
g.setColor(getRandColor(200,250));
g.fillRect(0, 0, width, height);
g.setColor(getRandColor(160,200));
for (int i=0;i<line;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);
}
g.setFont(font);
validate_code = getValidateCode(count,type);
request.getSession().setAttribute("validate_code",validate_code);
for (int i=0;i<count;i++){
g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
int x = (int)(width/count)*i;
int y = (int)((height+font.getSize())/2)-5;
g.drawString(String.valueOf(validate_code.charAt(i)),x,y);
}
g.dispose();
ImageIO.write(image, "JPEG", response.getOutputStream());
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
//TODO Method stub generated by Lomboz
doGet(request, response);
}
private Color getRandColor(int from,int to){
Random random = new Random();
if(to>255) from=255;
if(to>255) to=255;
int rang = Math.abs(to - from);
int r=from+random.nextInt(rang);
int g=from+random.nextInt(rang);
int b=from+random.nextInt(rang);
return new Color(r,g,b);
}
private String getValidateCode(int size,int type){
StringBuffer validate_code = new StringBuffer();
for(int i = 0; i < size; i++){
validate_code.append(getOneChar(type));
}
return validate_code.toString();
}
private String getOneChar(int type){
String result = null;
switch(type){
case TYPE_NUMBER:
result = String.valueOf(random.nextInt(10));
break;
case TYPE_LETTER:
result = String.valueOf((char)(random.nextInt(26)+65));
break;
case TYPE_MULTIPLE:
if(random.nextBoolean()){
result = String.valueOf(random.nextInt(10));
}else{
result = String.valueOf((char)(random.nextInt(26)+65));
}
break;
default:
result=null;
break;
}
if(result==null)throw new NullPointerException("获取验证码出错");
return result;
}
}
<%@ page language="java" pageEncoding="GB2312" %>
<!DOCTYPE HTML PUBLIC "-//w3c//dtd html 4.0 transitional//en">
<html>
<head>
<title>Lomboz JSP</title>
</head>
<body bgcolor="#FFFFFF">
<form action="check.jsp" method=post>
<table align=center>
<tr><td>
请输入验证码：<input type='text' name='validate_code' size=20>
</td><td>
<img src="ValidateCodeServlet" width=150 height=50>
</td></tr>
<tr><td>
<input type="submit" value="提交">
</td><td>
<input type="reset" value="重填">
</td></tr>
</table>
</body>
</html>
check.jsp:
<%@ page language="java" pageEncoding="GB2312" %>
<!DOCTYPE HTML PUBLIC "-//w3c//dtd html 4.0 transitional//en">
<html>
<head>
<title>Lomboz JSP</title>
</head>
<body bgcolor="#FFFFFF">
<%
String session_validate_code = (session.getAttribute("validate_code")).toString();
if(session_validate_code==null)System.out.println("validate code has not set");
else{
String request_code = request.getParameter("validate_code");
if(request_code==null)out.println("未输入");
else{
if(request_code.equalsIgnoreCase(session_validate_code))out.println("匹配");
else out.println("不匹配");
}
}
%>
</body>
</html>