java web验证码生成总结(包括servlet、jsp和struts2实现)

一、使用纯Servlet实现验证码

(1)在web.xml配置:

[java] view
plaincopy

<servlet>

<servlet-name>image</servlet-name>

<servlet-class>org.test.web.AuthImage</servlet-class>

</servlet>



<servlet-mapping>

<servlet-name>image</servlet-name>

<url-pattern>/authImage</url-pattern>

</servlet-mapping>

(2)servlet源码

[java] view
plaincopy

public class AuthImage extends HttpServlet

{



private static final String CONTENT_TYPE = "text/html; charset=gb2312";

//设置字母的大小,大小

private Font mFont = new Font("Times New Roman", Font.PLAIN, 17);

public void init() throws ServletException

{

super.init();

}

Color getRandColor(int fc,int bc)

{

Random random = new Random();

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);

}



public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException

{

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

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

response.setDateHeader("Expires", 0);

//表明生成的响应是图片

response.setContentType("image/jpeg");



int width=100, height=18;

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



Graphics g = image.getGraphics();

Random random = new Random();

g.setColor(getRandColor(200,250));

g.fillRect(1, 1, width-1, height-1);

g.setColor(new Color(102,102,102));

g.drawRect(0, 0, width-1, height-1);

g.setFont(mFont);



g.setColor(getRandColor(160,200));



//画随机线

for (int i=0;i<155;i++)

{

int x = random.nextInt(width - 1);

int y = random.nextInt(height - 1);

int xl = random.nextInt(6) + 1;

int yl = random.nextInt(12) + 1;

g.drawLine(x,y,x + xl,y + yl);

}



//从另一方向画随机线

for (int i = 0;i < 70;i++)

{

int x = random.nextInt(width - 1);

int y = random.nextInt(height - 1);

int xl = random.nextInt(12) + 1;

int yl = random.nextInt(6) + 1;

g.drawLine(x,y,x - xl,y - yl);

}



//生成随机数,并将随机数字转换为字母

String sRand="";

for (int i=0;i<6;i++)

{

int itmp = random.nextInt(26) + 65;

char ctmp = (char)itmp;

sRand += String.valueOf(ctmp);

g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));

g.drawString(String.valueOf(ctmp),15*i+10,16);

}



HttpSession session = request.getSession(true);

session.setAttribute("rand",sRand);

g.dispose();

ImageIO.write(image, "JPEG", response.getOutputStream());

}

public void destroy()

{

}

}

(3)页面显示

[java] view
plaincopy

<img src="authImage"/>







二、使用纯jsp实现验证码

[java] view
plaincopy

<%@ page language="java" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*"

contentType="image/jpeg" pageEncoding="UTF-8"%>





<% //设置页面不缓存

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

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

response.setDateHeader("Expires",0);

//在内存中创建图片

int width=60,height=20;

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

//获取图形上下文

Graphics g= image.getGraphics();

//生成随机类

Random random= new Random();

//设置背景颜色

g.setColor(new Color(160,200,100));

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

//设置字体

g.setFont(new Font("Times New Roman",Font.PLAIN,18));

//随机产生50条干扰线，使图形中的验证码不易被其他的程序探测到

g.setColor(new Color(160,200,200));

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

{

int x=random.nextInt(width);

int y=random.nextInt(height);

int x1=random.nextInt(width);

int y1=random.nextInt(height);

g.drawLine(x,y,x+x1,y+y1);

}

//随机产生验证码（6位数字）

String sRand="";

for(int i=0;i<6;i++)

{

String rand=String.valueOf(random.nextInt(10));

sRand+=rand;

//将验证码显示到图象

g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));

g.drawString(rand,13*i+6,16);

}

session.setAttribute("rand",sRand); //////将产生的验证码存储到sesson中

g.dispose();

ImageIO.write(image,"JPEG",response.getOutputStream());

out.clear(); //***********

out=pageContext.pushBody();//**********

%>





三、使用Struts2来实现验证码

(1)定义一个生成验证码的工具类

[java] view
plaincopy

package com.cn.hospital.util;



import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.imageio.stream.ImageOutputStream;



public class RandomNumUtil {



private ByteArrayInputStream image;//图像

private String str;//验证码



private RandomNumUtil(){

init();//初始化属性

}

/*

* 取得RandomNumUtil实例

*/

public static RandomNumUtil Instance(){

return new RandomNumUtil();

}

/*

* 取得验证码图片

*/

public ByteArrayInputStream getImage(){

return this.image;

}

/*

* 取得图片的验证码

*/

public String getString(){

return this.str;

}



private void init() {

// 在内存中创建图象

int width=85, height=20;

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

// 获取图形上下文

Graphics g = image.getGraphics();

// 生成随机类

Random random = new Random();

// 设定背景色

g.setColor(getRandColor(200,250));

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

// 设定字体

g.setFont(new Font("Times New Roman",Font.PLAIN,18));

// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到

g.setColor(getRandColor(160,200));

for (int i=0;i<155;i++)

{

int x = random.nextInt(width);

int y = random.nextInt(height);

int xl = random.nextInt(12);

int yl = random.nextInt(12);

g.drawLine(x,y,x+xl,y+yl);

}

// 取随机产生的认证码(6位数字)

String sRand="";

for (int i=0;i<6;i++){

String rand=String.valueOf(random.nextInt(10));

sRand+=rand;

// 将认证码显示到图象中

g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));

// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成

g.drawString(rand,13*i+6,16);

}

//赋值验证码

this.str=sRand;



//图象生效

g.dispose();

ByteArrayInputStream input=null;

ByteArrayOutputStream output = new ByteArrayOutputStream();

try{

ImageOutputStream imageOut = ImageIO.createImageOutputStream(output);

ImageIO.write(image, "JPEG", imageOut);

imageOut.close();

input = new ByteArrayInputStream(output.toByteArray());

}catch(Exception e){

System.out.println("验证码图片产生出现错误："+e.toString());

}



this.image=input;/* 赋值图像 */

}

/*

* 给定范围获得随机颜色

*/

private Color getRandColor(int fc,int bc){

Random random = new Random();

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);

}

}

(2)定义一个验证码输出的action

[java] view
plaincopy

package com.cn.hospital.action;



import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;



import org.springframework.context.annotation.Scope;

import org.springframework.stereotype.Controller;



import com.cn.hospital.util.RandomCharUtil;

import com.cn.hospital.util.RandomNumUtil;

import com.opensymphony.xwork2.ActionContext;

import com.opensymphony.xwork2.ActionSupport;



@Controller("utilAction")

@Scope("prototype")

public class UtilAction extends ActionSupport{



private static final long serialVersionUID = -7193209177116825032L;

private ByteArrayInputStream inputStream;



private int width;

private int height;

private int fontSize;

private int codeLength;

private int disturbType;



public String validNumGenerate() throws Exception{

RandomNumUtil rdnu=RandomNumUtil.Instance();

this.setInputStream(rdnu.getImage());//取得带有随机字符串的图片

ActionContext.getContext().getSession().put("random", rdnu.getString());//取得随机字符串放入HttpSession

return SUCCESS;

}





public void setInputStream(ByteArrayInputStream inputStream) {

this.inputStream = inputStream;

}



public ByteArrayInputStream getInputStream() {

return inputStream;

}





}

(3)struts.xml配置

[java] view
plaincopy

<!-- 产生随机验证码 -->

<action name="randNum" class="utilAction" method="validNumGenerate">

<result name="success" type="stream">

<param name="contentType">image/jpeg</param>

<param name="inputName">inputStream</param>

</result>

</action>