页面上输入验证码是比较常见的一个功能,实现起来也很简单.给大家写一个简单的生成验证码的示例程序,需要的朋友可以借鉴一下.

闲话少续,直接上代码.代码中的注释很详细.

package com.SM_test.utils;

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;

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++){

verifyCode.append(sources.charAt(rand.nextInt(codesLen-1)));

}

return verifyCode.toString();

}

/**

* 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();

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;

}

}

/**

* 输出指定验证码图片流

* @param w

* @param h

* @param os

* @param code

* @throws IOException

*/

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);// 设置边框色

g2.fillRect(0, 0, w, h);

Color c = getRandColor(200, 255);

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(50, 255));// 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.setColor(getRandColor(100, 160));

g2.drawChars(chars, i, 1, ((w-10) / verifySize) * i + 5, h-(h - (int)(fontSize*0.75))/2);

}

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:/abc");

int w = 200, h = 80;

for(int i = 0; i < 50; i++){

String verifyCode = generateVerifyCode(4);

File file = new File(dir, verifyCode + ".jpg");

outputImage(w, h, file, verifyCode);

}

}

}

上面这段代码就能生成一个验证码,略微修改就能生成各种各样的形式,main方法可以测试.

下面为大家写一下如何返回到页面

package com.SM_test.saomiao.constroller;

import java.io.IOException;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import com.SM_test.utils.VerifyCodeUtils;

@Controller

public class IndexConstroller {

@RequestMapping(value = "/index")

public void index(HttpServletRequest request,HttpServletResponse response) throws IOException{

response.setHeader("Pragma", "No-cache");

response.setHeader("Cache-Control", "no-cache");

response.setDateHeader("Expires", 0);

response.setContentType("image/jpeg");

//生成随机字串

String verifyCode = VerifyCodeUtils.generateVerifyCode(4);

//存入会话session

HttpSession session = request.getSession(true);

session.setAttribute("rand", verifyCode.toLowerCase());

//生成图片

int w = 200, h = 80;

VerifyCodeUtils.outputImage(w, h, response.getOutputStream(), verifyCode);

}

}

很简单,用HttpServletResponse 就OK了.

需要显示验证码的地方可以直接用img标签,地址就是该Controller的URL就OK了

以上所述是小编给大家介绍的Java生成验证码功能实例代码，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对脚本之家网站的支持！