JAVA生成安全性高的验证码图片

import java.awt.AlphaComposite;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics2D;

import java.awt.geom.AffineTransform;

import java.awt.image.BufferedImage;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.util.Random;

import java.util.UUID;

import javax.imageio.ImageIO;

/**

* 功能描述：

*

* @author 彭志(pengzhistar@sina.com.cn)

*

* <p>修改历史：(修改人，修改时间，修改原因/内容)</p>

*/

public class DrawIdentifyImgUtil {

final static String[] key = new String[]{"1","2","3","4","5","6","7","8","9","0","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};

static Random random = new Random();

private int width = 0;

private int height = 50;

public void setHeight(int height) {

this.height = height;

}

BufferedImage image = null;

public static String genCodeStr(int length){

StringBuffer buffer = new StringBuffer();

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

buffer.append(key[random.nextInt(key.length)]) ;

}

return buffer.toString();

}

public BufferedImage drawImg(String codeStr){

this.width = 38 * codeStr.length();

image = new BufferedImage(width, height,BufferedImage.TYPE_4BYTE_ABGR_PRE);

Graphics2D g = image.createGraphics();

// 绘制背景

// g.setColor(getRandomColor(200, 250));

//透明度设置

g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, 1.0f));

g.fillRect(0, 0, width, height);

g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER));

//混淆线

// drawRandomLines(g, 120);

//混淆文字

drawRandomText(g);

//干扰线

drawCenterLine(g);

StringBuffer strbuf = new StringBuffer();

// 定义字体样式

Font myFont = new Font("Consolas", Font.BOLD, 38);

boolean b = random.nextBoolean();

for (int i = 0; i < codeStr.length(); i++) {

String temp = String.valueOf(codeStr.charAt(i));

Color color = new Color(40 + random.nextInt(80), 40 + random.nextInt(80), 40 + random.nextInt(80));

g.setColor(color);

//旋转一定的角度

AffineTransform trans = new AffineTransform();

int rad = random.nextInt(30);

if(b = !b){

trans.rotate(Math.toRadians(rad),50 * (i) + 8, 30);

}else{

trans.rotate(Math.toRadians(-rad), 50 * (i) + 8 ,40);

}

// 缩放文字

float scaleSize = random.nextFloat() + 0.8f;

if (scaleSize > 1f){

scaleSize = 1f;

}

trans.scale(1f, 1f);

g.setTransform(trans);

//写文字

// 设置字体

g.setFont(myFont);

g.drawString(temp, 35 * i + (i == 0 ? 10 : 15), 40);

strbuf.append(temp);

}

g.dispose();

return image;

}

public void genImgFile(String fileFullName) throws FileNotFoundException,IOException {

FileOutputStream os = null;

try {

os = new FileOutputStream(new File(fileFullName));

ImageIO.write(image, "PNG", os);

} catch (FileNotFoundException e) {

throw e;

} catch (IOException e) {

throw e;

}finally{

if(os != null){

try {

os.close();

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

/**

* 功能描述：随机颜色

*

* @author 彭志(pengzhistar@sina.com.cn)

* <p>创建日期 ：2015年2月3日 下午4:08:37</p>

*

* @param fc

* @param bc

* @return

*

* <p>修改历史 ：(修改人，修改时间，修改原因/内容)</p>

*/

private Color getRandomColor(int fc, int bc) {

if (fc > 255)

fc = 200;

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);

}

/**

* 功能描述：混淆背景线

*

* @author 彭志(pengzhistar@sina.com.cn)

* <p>创建日期 ：2015年2月3日 下午4:10:08</p>

*

* @param g

* @param nums

*

* <p>修改历史 ：(修改人，修改时间，修改原因/内容)</p>

*/

private void drawRandomLines(Graphics2D g, int nums) {

int x1=0,y1=0;

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

g.setColor(this.getRandomColor(190, 230));

int x2 = random.nextInt(width);

int y2 = random.nextInt(height);

g.drawLine(x1, y1, x2, y2);

x1 = x2;

y1 = y2;

}

}

/**

* 功能描述：混淆文字

*

* @author 彭志(pengzhistar@sina.com.cn)

* <p>创建日期 ：2015年2月3日 下午4:09:59</p>

*

* @param g

*

* <p>修改历史 ：(修改人，修改时间，修改原因/内容)</p>

*/

private void drawRandomText(Graphics2D g){

Font myFont = new Font("Consolas", Font.HANGING_BASELINE, 30);

// 设置字体

g.setFont(myFont);

int max = 8 + random.nextInt(4);

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

g.setColor(this.getRandomColor(170, 220));

String temp = key[random.nextInt(key.length)] ;

g.drawString(temp ,i * 24,random.nextInt(height));

}

}

/**

* 功能描述：中间混淆线

*

* @author 彭志(pengzhistar@sina.com.cn)

* <p>创建日期 ：2015年2月3日 下午4:09:42</p>

*

* @param g

*

* <p>修改历史 ：(修改人，修改时间，修改原因/内容)</p>

*/

private void drawCenterLine(Graphics2D g){

Random random = new Random();

int py = 3 + random.nextInt(6);

int x1 = 0, y1 = height/2 , y2 = height/2-1 ;

boolean minus = true;

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

g.setColor(this.getRandomColor(60, 80));

g.drawLine(x1, y1, x1, y2);

x1++;

if(minus ){

y1--;y2--;

}else{

y1++;y2++;

}

if(Math.abs(y1 - height/2) > py){

minus = !minus;

py = 3 + random.nextInt(6);

}

}

}

public static void main(String[] args) {

DrawIdentifyImgUtil idCode = new DrawIdentifyImgUtil();

for (int i = 0; i < 100 ;i++) {

System.out.println(UUID.randomUUID().toString());

String codeStr = idCode.genCodeStr(4);

idCode.drawImg(codeStr);

try {

idCode.genImgFile("d:\\img\\"+codeStr+".png");

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

效果图：


Servlet中使用方式

String checkCode = "1234";

DrawIdentifyImgUtil draw = new DrawIdentifyImgUtil();

BufferedImage image = draw.drawImg(checkCode);

OutputStream os = null;

try {

os = response.getOutputStream();

ImageIO.write(image, "PNG", os);

image.flush();

} catch (IOException e) {

e.printStackTrace();

}finally{

if(os != null){

try {

os.close();

} catch (IOException e) {

e.printStackTrace();

}

}

}