这篇随笔主要是java中制作验证码的效果，由于是在国庆前做的，现在也找不到原载了。我对自己整理的发表一份
生成的验证码效果如下：
一、建立一个工具类，用来生成验证码
package com.dkt.util; import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.Random; import javax.imageio.ImageIO;
/**
* <p><b>VerifyCodeUtils Description:</b> (验证码生成)</p>
* <b>DATE:</b> 2016年6月2日 下午3:53:34
*/
public class VerifyCodeUtils{ //使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符
public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
private static Random random = new Random(); /**
* 使用系统默认字符源生成验证码
* @param verifySize 验证码长度
* @return
*/
public static String generateVerifyCode(int verifySize){
return generateVerifyCode(verifySize, VERIFY_CODES);
}
/**
* 使用指定源生成验证码
* @param verifySize 验证码长度
* @param sources 验证码字符源
* @return
*/
public static String generateVerifyCode(int verifySize, String sources){
if(sources == null || sources.length() == 0){
sources = VERIFY_CODES;
}
int codesLen = sources.length();
Random rand = new Random(System.currentTimeMillis());
StringBuilder verifyCode = new StringBuilder(verifySize);
for(int i = 0; i < verifySize; i++){
//随机在验证字符中取一个值
verifyCode.append(sources.charAt(rand.nextInt(codesLen-1)));
}
return verifyCode.toString();//得到四位数的验证码
} /**
* 生成随机验证码文件,并返回验证码值
* @param w
* @param h
* @param outputFile
* @param verifySize
* @return
* @throws IOException
*/
public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException{
String verifyCode = generateVerifyCode(verifySize);
outputImage(w, h, outputFile, verifyCode);
return verifyCode;
} /**
* 输出随机验证码图片流,并返回验证码值
* @param w
* @param h
* @param os
* @param verifySize
* @return
* @throws IOException
*/
public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException{
String verifyCode = generateVerifyCode(verifySize);
outputImage(w, h, os, verifyCode);
return verifyCode;
} /**
* 生成指定验证码图像文件
* @param w
* @param h
* @param outputFile
* @param code
* @throws IOException
*/
public static void outputImage(int w, int h, File outputFile, String code) throws IOException{
if(outputFile == null){
return;
}
File dir = outputFile.getParentFile();//文件目录
if(!dir.exists()){
dir.mkdirs();
}
try{
outputFile.createNewFile();//创建文件
FileOutputStream fos = new FileOutputStream(outputFile);
outputImage(w, h, fos, code);
fos.close();
} catch(IOException e){
throw e;
}
} /**
* 输出指定验证码图片流
* @param w 宽
* @param h 高
* @param os 输出流方式
* @param code 验证码
* @throws IOException
*/
public static void outputImage(int w, int h, OutputStream os, String code) throws IOException{
int verifySize = code.length();
//类型为预定义图像类型之一的 BufferedImage。
BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Random rand = new Random();
Graphics2D g2 = image.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
Color[] colors = new Color[5];
Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN,
Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
Color.PINK, Color.YELLOW };
float[] fractions = new float[colors.length];
for(int i = 0; i < colors.length; i++){
colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
fractions[i] = rand.nextFloat();
}
Arrays.sort(fractions); g2.setColor(Color.GRAY);// 设置边框色
g2.fillRect(0, 0, w, h); Color c = getRandColor(200, 250);
g2.setColor(c);// 设置背景色
g2.fillRect(0, 2, w, h-4); //绘制干扰线
Random random = new Random();
g2.setColor(getRandColor(160, 200));// 设置线条的颜色
for (int i = 0; i < 20; i++) {
int x = random.nextInt(w - 1);
int y = random.nextInt(h - 1);
int xl = random.nextInt(6) + 1;
int yl = random.nextInt(12) + 1;
g2.drawLine(x, y, x + xl + 40, y + yl + 20);
} // 添加噪点
float yawpRate = 0.05f;// 噪声率
int area = (int) (yawpRate * w * h);
for (int i = 0; i < area; i++) {
int x = random.nextInt(w);
int y = random.nextInt(h);
int rgb = getRandomIntColor();
image.setRGB(x, y, rgb);
} shear(g2, w, h, c);// 使图片扭曲 g2.setColor(getRandColor(100, 160));
int fontSize = h-4;
Font font = new Font("Algerian", Font.ITALIC, fontSize);
g2.setFont(font);
char[] chars = code.toCharArray();
for(int i = 0; i < verifySize; i++){
AffineTransform affine = new AffineTransform();
affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize/2, h/2);
g2.setTransform(affine);
g2.drawChars(chars, i, 1, ((w-10) / verifySize) * i + 5, h/2 + fontSize/2 - 10);
} g2.dispose();
ImageIO.write(image, "jpg", os);
} private static Color getRandColor(int fc, int bc) {
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);
} private static int getRandomIntColor() {
int[] rgb = getRandomRgb();
int color = 0;
for (int c : rgb) {
color = color << 8;
color = color | c;
}
return color;
} private static int[] getRandomRgb() {
int[] rgb = new int[3];
for (int i = 0; i < 3; i++) {
rgb[i] = random.nextInt(255);
}
return rgb;
} private static void shear(Graphics g, int w1, int h1, Color color) {
shearX(g, w1, h1, color);
shearY(g, w1, h1, color);
} private static void shearX(Graphics g, int w1, int h1, Color color) { int period = random.nextInt(2); boolean borderGap = true;
int frames = 1;
int phase = random.nextInt(2); for (int i = 0; i < h1; i++) {
double d = (double) (period >> 1)
* Math.sin((double) i / (double) period
+ (6.2831853071795862D * (double) phase)
/ (double) frames);
g.copyArea(0, i, w1, 1, (int) d, 0);
if (borderGap) {
g.setColor(color);
g.drawLine((int) d, i, 0, i);
g.drawLine((int) d + w1, i, w1, i);
}
} } private static void shearY(Graphics g, int w1, int h1, Color color) { int period = random.nextInt(40) + 10; // 50; boolean borderGap = true;
int frames = 20;
int phase = 7;
for (int i = 0; i < w1; i++) {
double d = (double) (period >> 1)
* Math.sin((double) i / (double) period
+ (6.2831853071795862D * (double) phase)
/ (double) frames);
g.copyArea(i, 0, 1, h1, 0, (int) d);
if (borderGap) {
g.setColor(color);
g.drawLine(i, (int) d, i, 0);
g.drawLine(i, (int) d + h1, i, h1);
} } }
public static void main(String[] args) throws IOException{
File dir = new File("e:/verifies");// 生成的验证码存放目录
int w = 200, h = 80; String verifyCode = generateVerifyCode(4);
File file = new File(dir, verifyCode + ".jpg");
outputImage(w, h, file, verifyCode); /*String verifyCode = generateVerifyCode(4);
System.out.println(verifyCode);*/ }
}
二、建立一个CodeEnt实体类
package com.dkt.entity;
public class CodeEnt {
private String code;//验证码
private long nowtime;//失效的毫秒时间
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public long getNowtime() {
return nowtime;
}
public void setNowtime(long nowtime) {
this.nowtime = nowtime;
}
public CodeEnt(String code, long nowtime) {
super();
this.code = code;
this.nowtime = nowtime;
}
public CodeEnt() {
super();
}
}
三、建立servlet类，作为服务器，调用上面的类生成验证码，并把验证码发送到页面，且验证验证码输入是否正确
我在这里为了方便理解，建立了两个servlet类，
一个类是 AuthImage 就是用来调用工具类 VerifyCodeUtils ,生成验证码并发送到页面上
package com.dkt.servlet; import java.io.IOException; 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.dkt.entity.CodeEnt;
import com.dkt.util.VerifyCodeUtils; public class AuthImage extends HttpServlet {
static final long serialVersionUID = 1L;
public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setHeader("Pragma", "No-cache"); //不缓存
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
response.setContentType("image/jpeg"); //输出的图片 //生成随机字串
String verifyCode = VerifyCodeUtils.generateVerifyCode(4);
//存入会话session
HttpSession session = request.getSession();
//保存
long nowtime = System.currentTimeMillis();
CodeEnt codeEnt = new CodeEnt(verifyCode, nowtime);
session.setAttribute("codeent", codeEnt);
//生成图片 并发送到页面中
int w = 100, h = 30;
VerifyCodeUtils.outputImage(w, h, response.getOutputStream(), verifyCode); }
}
另一个类是 CodeServlet 主要是判断用户输入的验证码是否正确，并给出提示
package com.dkt.servlet; import java.io.IOException;
import java.util.Calendar; 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.dkt.entity.CodeEnt; public class CodeServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html");
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
//存入会话session
HttpSession session = request.getSession();
String op = request.getParameter("op");
if (("reg").equals(op)) {
// 判断用户输入的验证是否正确且没有超时
String code = request.getParameter("code");
System.out.println("code--------->"+code);
if (code!=null&&!("").equals(code)) {
code = code.toUpperCase();//全部转成大写字母
}
CodeEnt codeEnt = (CodeEnt)session.getAttribute("codeent");
long nowT = Calendar.getInstance().getTimeInMillis();
//System.out.println(System.currentTimeMillis());
//System.out.println(nowT);
long diffT = nowT-codeEnt.getNowtime();
System.out.println("时间差："+diffT);
if (diffT<30000) {
if (code.equals(codeEnt.getCode())) {
System.out.println("验证成功");
request.getRequestDispatcher("success.jsp").forward(request, response);
}else {
request.setAttribute("error", "验证码输入错误，请重新输入");
request.getRequestDispatcher("verify.jsp").forward(request, response);
}
}else {
//验证不成功重新刷新验证码
request.setAttribute("error", "验证码失效，请重新刷新");
request.getRequestDispatcher("verify.jsp").forward(request, response);
}
}else {
System.out.println("else");
} }
}
四，xml中的配置信息
<?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>AuthImage</servlet-name>
<servlet-class>com.dkt.servlet.AuthImage</servlet-class>
</servlet>
<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>CodeServlet</servlet-name>
<servlet-class>com.dkt.servlet.CodeServlet</servlet-class>
</servlet> <servlet-mapping>
<servlet-name>AuthImage</servlet-name>
<url-pattern>/AuthImage</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>CodeServlet</servlet-name>
<url-pattern>/CodeServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>verify.jsp</welcome-file>
</welcome-file-list>
</web-app>
五、写页面 jsp ，添加事件
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>"> <title>My JSP 'verify.jsp' starting page</title> <meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
--> <script type="text/javascript">
function change(img){
img.src = img.src+"?"+new Date();
} </script>
</head> <body>
<form action="CodeServlet?op=reg" method="post">
<span style="font-size: 12px;color: red;">${error}</span><br/>
用户名：<input type="text" name="name" value=""><br/><br/>
验证码：<input type="text" name="code" value=""/>
<img src="AuthImage" alt="验证码" onclick="change(this)"/>
<input type="submit" value="提交">
</form>
</body>
</html>
五、执行结果
启动服务器，在浏览器地址栏中访问，
当输入错误时，会显示：
当输入时验证码失效时，会提示：
输入成功时会跳到 success.jsp 页面，这个页面就请大家自己随便写洛。