java生成图片验证码实例代码

java生成图片验证码实例代码

生成图片验证码类

package spring_mvc_test.utils;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics2D;

import java.awt.image.BufferedImage;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.servlet.ServletException;

import javax.servlet.ServletOutputStream;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

/**

 * 图片验证码生成类

 *

 */

public class ImgVerifyCodeUtils extends HttpServlet{

/**
* 
*/
private static final long serialVersionUID = 1L;

/**
*  验证码图片的宽度
*/
private int width = 70;

/**
* 验证码图片的高度
*/
private int height = 30;

/**
* 验证码字符个数
*/
private int codeCount = 5;

/**
* 生成随机数的水平距离
*/
private int xx = 0;

/**
* 生成随机数的数字高度
*/
private int fontHeight;

/**
* 生成随机数的垂直距离
*/
private int codeY;

/**
* 验证码序列
*/
private String[] codeSequence = {"1" , "2" , "3" , "4" , "5" ,"6","7","8","9","A","a","B","b","c","C"
      ,"D","d","E","e","F","f","G","g","z","X","Q","v"};

public ImgVerifyCodeUtils(int width, int height, int codeCount, int xx, int fontHeight, int codeY,
String[] codeSequence) {
super();
this.width = width;
this.height = height;
this.codeCount = codeCount;
this.xx = xx;
this.fontHeight = fontHeight;
this.codeY = codeY;
this.codeSequence = codeSequence;
}

public ImgVerifyCodeUtils() {
super();
}

public int getWidth() {
return width;
}

public void setWidth(int width) {
this.width = width;
}

public int getHeight() {
return height;
}

public void setHeight(int height) {
this.height = height;
}

public int getCodeCount() {
return codeCount;
}

public void setCodeCount(int codeCount) {
this.codeCount = codeCount;
}

public int getXx() {
return xx;
}

public void setXx(int xx) {
this.xx = xx;
}

public int getFontHeight() {
return fontHeight;
}

public void setFontHeight(int fontHeight) {
this.fontHeight = fontHeight;
}

public int getCodeY() {
return codeY;
}

public void setCodeY(int codeY) {
this.codeY = codeY;
}

public String[] getCodeSequence() {
return codeSequence;
}

public void setCodeSequence(String[] codeSequence) {
this.codeSequence = codeSequence;
}

public static long getSerialversionuid() {
return serialVersionUID;
}

/**
* 初始化验证图片属性
*/
public void init() throws ServletException {
//高度
String strWidth = width + "";
//宽度
String strHeight = height + "";
//字符个数
String strCodeCount = codeCount + "";

//此处这么写，代表可以随时更改告诉，在程序运行时改变
try{
if (strWidth != null && strWidth.length() != 0) {
       width = Integer.parseInt(strWidth);
     }
     if (strHeight != null && strHeight.length() != 0) {
       height = Integer.parseInt(strHeight);
     }
     if (strCodeCount != null && strCodeCount.length() != 0) {
       codeCount = Integer.parseInt(strCodeCount);
     }
}catch(Exception e){
e.printStackTrace();
}
//生成随机数的水平距离
xx = width/(codeCount + 2);
//生成随机数的数字高度
fontHeight = height - 12;
//生成随机数的垂直距离
codeY = height - 8;

}

public String createImageCode(HttpServletReq
c69f
uest req , HttpServletResponse resp) throws Exception{
init();
//自定义图像buffer
BufferedImage buffImg = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
Graphics2D gd = buffImg.createGraphics();

Random random = new Random();
//将图片填充为白色
gd.setColor(Color.WHITE);
gd.fillRect(0, 0, width, height);
//创建字体，字体的大小根据图片的高度来定
Font font = new Font("Fixedsys",Font.PLAIN,fontHeight);
//设置字体
gd.setFont(font);
//画边框
gd.setColor(Color.BLACK);
gd.drawRect(0, 0, width - 1, height - 1);
//随机产生4条干扰线，使图像中的认证码不易被其他程序探测到。
gd.setColor(Color.BLACK);
for(int i = 0 ; i < 4; i ++){
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(12);
int yl = random.nextInt(12);
gd.drawLine(x, y, x + xl, y + yl);
}
//randomCode用于保存随机产生的验证码，以便用户登录后进行验证。
StringBuffer randomCode = new StringBuffer();
int red = 0;
int green = 0;
int blue = 0;

//随机产生codeCount数字的验证码。
for(int i = 0 ; i < codeCount ; i ++){
//得到随机产生的验证码数字。
String strRand = String.valueOf(codeSequence[random.nextInt(27)]);
//产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同。
red = random.nextInt(125);
green = random.nextInt(255);
blue = random.nextInt(200);

//用随机产生的颜色将验证码绘制到图像中。
gd.setColor(new Color(red,green,blue));
gd.drawString(strRand, (i + 1) * xx, codeY);

//将产生的四个随机数组合在一起
randomCode.append(strRand);
}
//将四位数字的验证码保存到Session中。
HttpSession session = req.getSession();
session.setAttribute("validataCode", randomCode.toString());

//禁止图像缓存
resp.setHeader("Pragma", "no-cache");
resp.setHeader("Cache-Control", "no-cache");
resp.setDateHeader("Expires", 0);

resp.setContentType("image/jpeg");

//将图像输出到Servlet输出流中
ServletOutputStream sos = resp.getOutputStream();
ImageIO.write(buffImg, "jpeg", sos);
sos.close();

return null;
}

}