java圖片驗證碼

最後更新：2018-12-05 來源：互聯網

上載者：User

創建阿里雲帳戶，並獲得超過 40 款產品的免費試用版；而企業帳戶則可以享有總值 $1200 的免費試用版。立即註冊！

第一步：建立一個Servlet檔案
//數字隨機碼
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"); //要設定好一個圖片
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);
}
}

第二步設定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>

第三步建立相應的JSP
index.jsp
<%@ page contentType="text/html;charset=gb2312"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>認證碼輸入頁面</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">

Check.jsp
<%@ page contentType="text/html; charset=gb2312" language="java"
errorPage=""%>
<html>
<head>
<title>認證碼驗證頁面</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");
%>
系統產生的認證碼為：
<%=rand%><br>
您輸入的認證碼為：
<%=input%><br>
<br>
<%
if (rand.equals(input)) {
%>
<font color=green>輸入相同，認證成功！</font>
<%
} else {
%>
<font color=red>輸入不同，認證失敗！</font>
<%
}
%>
</body>
</html>
==================
長生字元和資料的驗證碼

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();
}

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);
}
}
}

本文章原先以中文撰寫並發佈於 aliyun.com，亦設英文版本，僅作資訊用途。本網站不對文章的準確性，完整性或可靠性或其任何翻譯作出任何明示或暗示的陳述或保證。如對該文章有任何疑慮或投訴，請傳送電郵至 info-contact@alibabacloud.com 並提供相關疑慮或投訴的詳細說明。職員會於 5 個工作天內與您聯絡，一經驗證之後，即會刪除該侵權內容。

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

Sales Support

1 on 1 presale consultation

Chat Contact Sales
After-Sales Support

24/7 Technical Support 6 Free Tickets per Quarter Faster Response

Open a Ticket
Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

Learn More