在javaweb项目中添加验证码并进行验证
生成图片的代码
package cn.itcast.uitil;
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;
/**
* 验证码
*/
public class VerifyCodeUtils{
public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
private static Random random = new Random();
public static String generateVerifyCode(int verifySize){
return generateVerifyCode(verifySize, VERIFY_CODES);
}
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++){
verifyCode.append(sources.charAt(rand.nextInt(codesLen-1)));
}
return verifyCode.toString();
}
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;
}
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;
}
public static void outputImage(int w, int h, File outputFile, String code) throws IOException{
if(outputFile == null){
return;
}
File dir = outputFile.getParentFile();
if(!dir.exists()){
dir.mkdirs();
}
try{
outputFile.createNewFile();
FileOutputStream fos = new FileOutputStream(outputFile);
outputImage(w, h, fos, code);
fos.close();
} catch(IOException e){
throw e;
}
}
public static void outputImage(int w, int h, OutputStream os, String code) throws IOException{
int verifySize = code.length();
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);
g2.fillRect(0, 0, w, h);
Color c = getRandColor(200, 250);
g2.setColor(c);
g2.fillRect(0, 2, w, h-4);
Random random = new Random();
g2.setColor(getRandColor(160, 200));
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);
}
float yawpRate = 0.05f;
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);
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;
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{
// 定义图片目录
File dir = new File("d:/verifies");
// 定义图片大小
int w = 200, h = 80;
// 生成 50 个验证码图片
for(int i = 0; i < 50; i++){
// 随机生成验证码
String verifyCode = generateVerifyCode(4);
// 生成图片文件
File file = new File(dir, verifyCode + ".jpg");
// 输出图片
outputImage(w, h, file, verifyCode);
}
}
}
VerifyCodeUtils.java文件的代码中你只需要知道其图片或自动存放在d:/verifies目录下
Servlet动态获取验证码代码
package cn.itcast.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import cn.itcast.uitil.VerifyCodeUtils;
@WebServlet("/vcode.s")
public class VcodeSelvlet extends BasicServlet {
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
/**
* 页面中图片的设置
* 
* Servlet动态获取验证码
*/
// 定义图片大小
int w = 200, h = 80;
// 随机生成验证码
String verifyCode = VerifyCodeUtils.generateVerifyCode(4);
// 将验证码添加到会话中，注意：在会话中保存的验证码的名称 vscode
request.getSession().setAttribute("vscode", verifyCode);
// 图形写给浏览器
response.setContentType("image/jpeg");
// 发头控制浏览器不要缓存
response.setDateHeader("expries", -1);
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Pragma", "no-cache");
// 输出图片
VerifyCodeUtils.outputImage(w, h, response.getOutputStream(),
verifyCode);
}
}
VcodeSelvlet.java文件中你只需要知道 VcodeSelvlet的映射地址为vcode.s，在会话中保存的验证码的名称 vscode。
在jsp中操作验证码的部分代码
src="vcode.s";是指其图片的路径从VcodeSelvlet中获取
οnclick='src="vcode.s?"+new Date()' ;是指根据点击事件根据时间的不同从而动态获取不同的图片。从而起到每点击一次获取不同的验证码效果
在Servlet中比较jsp界面上验证码是否输入正确
String vcode = request.getParameter("vcode");//获取输入框中的值
String cscode = (String) request.getSession().getAttribute("vscode");//获取图片上验证码的值
//不区分大小写
if(vcode.equalsIgnoreCase(cscode)){
System.out.println("您的值与验证码的值一致");
}else{
System.out.println("您的值与验证码的值不一致");
}String cscode = (String) request.getSession().getAttribute("vscode");//获取图片上验证码的值。
在前面说过在会话中保存的验证码的名称 vscode。所以可以通过 (String) request.getSession().getAttribute("vscode");来获取验证码的值。