java图片验证码

左手的ㄟ右手 2022-08-07 06:37 244阅读 0赞

第一步：创建一个Servlet文件  
//数字随机码  
public class generateCode extends HttpServlet \{  
private static final long serialVersionUID = 5039673797977591965L;  
  
protected void doGet(HttpServletRequest req, HttpServletResponse resp)  
throws ServletException, IOException \{  
processRequest(req, resp);  
\}  
  
protected void doPost(HttpServletRequest req, HttpServletResponse resp)  
throws ServletException, IOException \{  
processRequest(req, resp);  
\}  
  
public void processRequest(HttpServletRequest request,  
HttpServletResponse response) throws IOException \{  
response.setContentType("11.gif"); //要设定好一个图片  
response.setHeader("Pragma", "No-cache");  
response.setHeader("Cache-Control", "no-cache");  
response.setDateHeader("Expires", 0);  
HttpSession session = request.getSession();  
int width = 80, height = 20;  
BufferedImage image = new BufferedImage(width, height,  
BufferedImage.TYPE\_INT\_RGB);  
Graphics g = image.getGraphics();  
Random random = new Random();  
g.setColor(getRandColor(200, 250));  
g.fillRect(0, 0, width, height);  
  
g.setFont(new Font("Times New Roman", Font.PLAIN, 18));  
g.setColor(getRandColor(160, 200));  
for (int i = 0; i < 155; 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);  
\}  
  
String sRand = "";  
for (int i = 0; i < 6; i++) \{  
String rand = String.valueOf(random.nextInt(10));  
sRand += rand;  
g.setColor(new Color(20 + random.nextInt(110), 20 + random  
.nextInt(110), 20 + random.nextInt(110)));  
g.drawString(rand, 13 \* i + 6, 16);  
\}  
session.setAttribute("rand", sRand);  
g.dispose();  
ServletOutputStream responseOutputStream = response.getOutputStream();  
ImageIO.write(image, "JPEG", responseOutputStream);  
responseOutputStream.flush();  
responseOutputStream.close();  
\}  
  
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);  
\}  
\}  
  
**第二步 设置web.xml**  
  
        <servlet>  
<servlet-name>showImgCode</servlet-name>  
<servlet-class>generateCode </servlet-class>  
</servlet>  
<servlet-mapping>  
<servlet-name>showImgCode</servlet-name>  
<url-pattern>/11.GIF</url-pattern>  
</servlet-mapping>  
  
**第三步 创建相应的JSP**  
index.jsp  
<%@ page contentType="text/html;charset=gb2312"%>  
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">  
<html>  
<head>  
<title>认证码输入页面</title>  
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">  
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">  
<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache">  
<META HTTP-EQUIV="Expires" CONTENT="0">  
  
<script language="JavaScript">  
          function myrefresh()  
          \{  
            window.location.reload();  
          \}  
      </script>  
</head>  
<body>  
<form method=post action="check.jsp">  
<table>  
<tr>  
<td align=left>  
系统产生的认证码：  
</td>  
<td>  
<img border=0 src="11.GIF">  
<input type="button" value="看不清，在换一张" οnclick="myrefresh()">  
</td>  
</tr>  
<tr>  
<td align=left>  
输入上面的认证码：  
</td>  
<td>  
<input type=text name=rand maxlength=6 value="">  
</td>  
</tr>  
<tr>  
<td colspan=2 align=center>  
<input type=submit value="提交检测">  
</td>  
</tr>  
</table>  
</form>  
</body>  
</html>  
  
**Check.jsp**  
<%@ page contentType="text/html; charset=gb2312" language="java"  
errorPage=""%>  
<html>  
<head>  
<title>认证码验证页面</title>  
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">  
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">  
<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache">  
<META HTTP-EQUIV="Expires" CONTENT="0">  
</head>  
<body>  
<%  
String rand = (String) session.getAttribute("rand");  
String input = request.getParameter("rand");  
%>  
系统产生的认证码为：  
<%=rand%><br>  
您输入的认证码为：  
<%=input%><br>  
<br>  
<%  
if (rand.equals(input)) \{  
%>  
<font color=green>输入相同，认证成功！</font>  
<%  
\} else \{  
%>  
<font color=red>输入不同，认证失败！</font>  
<%  
\}  
%>  
</body>  
</html>  
==================  
**长生字符和数据的验证码**  
  
  
public class CharactorCode extends HttpServlet \{  
private static final long serialVersionUID = 4347521091342882490L;  
private Font mFont = new Font("Arial Black", Font.PLAIN, 16);  
  
public void init() throws ServletException \{  
super.init();  
\}  
  
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);  
\}  
  
public void service(HttpServletRequest request, HttpServletResponse response)  
throws ServletException, IOException \{  
response.setHeader("Pragma", "No-cache");  
response.setHeader("Cache-Control", "no-cache");  
response.setDateHeader("Expires", 0);  
response.setContentType("11.gif");  
  
int width = 100, height = 18;  
BufferedImage image = new BufferedImage(width, height,  
BufferedImage.TYPE\_INT\_RGB);  
  
Graphics g = image.getGraphics();  
Random random = new Random();  
g.setColor(getRandColor(200, 250));  
g.fillRect(1, 1, width - 1, height - 1);  
g.setColor(new Color(102, 102, 102));  
g.drawRect(0, 0, width - 1, height - 1);  
g.setFont(mFont);  
  
g.setColor(getRandColor(160, 200));  
for (int i = 0; i < 155; i++) \{  
int x = random.nextInt(width - 1);  
int y = random.nextInt(height - 1);  
int xl = random.nextInt(6) + 1;  
int yl = random.nextInt(12) + 1;  
g.drawLine(x, y, x + xl, y + yl);  
\}  
for (int i = 0; i < 70; i++) \{  
int x = random.nextInt(width - 1);  
int y = random.nextInt(height - 1);  
int xl = random.nextInt(12) + 1;  
int yl = random.nextInt(6) + 1;  
g.drawLine(x, y, x - xl, y - yl);  
\}  
  
String sRand = "";  
for (int i = 0; i < 6; i++) \{  
String tmp = getRandomChar();  
sRand += tmp;  
g.setColor(new Color(20 + random.nextInt(110), 20 + random  
.nextInt(110), 20 + random.nextInt(110)));  
g.drawString(tmp, 15 \* i + 10, 15);  
\}  
  
HttpSession session = request.getSession(true);  
session.setAttribute("rand", sRand);  
g.dispose();  
ImageIO.write(image, "JPEG", response.getOutputStream());  
\}  
  
private String getRandomChar() \{  
int rand = (int) Math.round(Math.random() \* 2);  
long itmp = 0;  
char ctmp = '/u0000';  
switch (rand) \{  
case 1:  
itmp = Math.round(Math.random() \* 25 + 65);  
ctmp = (char) itmp;  
return String.valueOf(ctmp);  
case 2:  
itmp = Math.round(Math.random() \* 25 + 97);  
ctmp = (char) itmp;  
return String.valueOf(ctmp);  
default:  
itmp = Math.round(Math.random() \* 9);  
return String.valueOf(itmp);  
\}  
\}  
\}