JavaWeb生成图片验证码

做一个登录页面，添加图片验证码，需要页面，Action跳转，struts.xml传输图像数据，随机生成字符的类，还有使用随机字符生成图片的类。剩下就是页面登录时，生成图片，数据校验进行匹配了。ValidateCode.java

import java.util.Arrays;

/**
* 工具类，生成随机验证码字符串
* @version 1.0 2012/08/21
* @author
*
*/
public class ValidateCode {

/**
* 验证码难度级别，Simple只包含数字，Medium包含数字和小写英文，Hard包含数字和大小写英文
*/
public enum SecurityCodeLevel {Simple,Medium,Hard};

/**
* 产生默认验证码，4位中等难度
* @return  String 验证码
*/
public static String getSecurityCode(){
return getSecurityCode(4,SecurityCodeLevel.Medium,false);
}

/**
* 产生长度和难度任意的验证码
* @param length  长度
* @param level   难度级别
* @param isCanRepeat  是否能够出现重复的字符，如果为true，则可能出现 5578这样包含两个5,如果为false，则不可能出现这种情况
* @return  String 验证码
*/
public static String getSecurityCode(int length,SecurityCodeLevel level,boolean isCanRepeat){

//随机抽取len个字符
int len=length;

//字符集合(除去易混淆的数字0、数字1、字母l、字母o、字母O)
char[] codes={'1','2','3','4','5','6','7','8','9',
'a','b','c','d','e','f','g','h','i',
'j','k','m','n','p','q','r','s','t',
'u','v','w','x','y','z','A','B','C',
'D','E','F','G','H','I','J','K','L',
'M','N','P','Q','R','S','T','U','V',
'W','X','Y','Z'};

//根据不同的难度截取字符数组
if(level==SecurityCodeLevel.Simple){
codes=Arrays.copyOfRange(codes, 0,9);
}else if(level==SecurityCodeLevel.Medium){
codes=Arrays.copyOfRange(codes, 0,33);
}

//字符集合长度
int n=codes.length;

//抛出运行时异常
if(len>n&&isCanRepeat==false){
throw new RuntimeException(
String.format("调用SecurityCode.getSecurityCode(%1$s,%2$s,%3$s)出现异常，" +
"当isCanRepeat为%3$s时，传入参数%1$s不能大于%4$s",
len,level,isCanRepeat,n));
}

//存放抽取出来的字符
char[] result=new char[len];

//判断能否出现重复的字符
if(isCanRepeat){
for(int i=0;i<result.length;i++){
//索引 0 and n-1
int r=(int)(Math.random()*n);

//将result中的第i个元素设置为codes[r]存放的数值
result[i]=codes[r];
}
}else{
for(int i=0;i<result.length;i++){
//索引 0 and n-1
int r=(int)(Math.random()*n);

//将result中的第i个元素设置为codes[r]存放的数值
result[i]=codes[r];

//必须确保不会再次抽取到那个字符，因为所有抽取的字符必须不相同。
//因此，这里用数组中的最后一个字符改写codes[r]，并将n减1
codes[r]=codes[n-1];
n--;
}
}

return String.valueOf(result);
}
}

ValidateImg.java

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.io.IOException;
import java.util.Random;
import com.sun.image.codec.jpeg.ImageFormatException;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

/**
* 工具类，生成验证码图片
* @version 1.0 2012/08/21
* @author
*
*/
public class ValidateImage {

/**
* 生成验证码图片
* @param securityCode   验证码字符
* @return  BufferedImage  图片
*/
public static BufferedImage createImage(String securityCode){

//验证码长度
int codeLength=securityCode.length();
//字体大小
int fSize = 15;
int fWidth = fSize + 1;
//图片宽度
int width = codeLength * fWidth + 6 ;
//图片高度
int height = fSize * 2 + 1;

//图片
BufferedImage image=new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g=image.createGraphics();

//设置背景色
g.setColor(Color.WHITE);
//填充背景
g.fillRect(0, 0, width, height);

//设置边框颜色
g.setColor(Color.LIGHT_GRAY);
//边框字体样式
g.setFont(new Font("Arial", Font.BOLD, height - 2));
//绘制边框
g.drawRect(0, 0, width - 1, height -1);

//绘制噪点
Random rand = new Random();
//设置噪点颜色
g.setColor(Color.LIGHT_GRAY);
for(int i = 0;i < codeLength * 6;i++){
int x = rand.nextInt(width);
int y = rand.nextInt(height);
//绘制1*1大小的矩形
g.drawRect(x, y, 1, 1);
}

//绘制验证码
int codeY = height - 10;
//设置字体颜色和样式
g.setColor(new Color(19,148,246));
g.setFont(new Font("Georgia", Font.BOLD, fSize));
for(int i = 0; i < codeLength;i++){
g.drawString(String.valueOf(securityCode.charAt(i)), i * 16 + 5, codeY);
}
//关闭资源
g.dispose();

return image;
}

/**
* 返回验证码图片的流格式
* @param securityCode  验证码
* @return ByteArrayInputStream 图片流
*/
public static ByteArrayInputStream getImageAsInputStream(String securityCode){

BufferedImage image = createImage(securityCode);
return convertImageToStream(image);
}

/**
* 将BufferedImage转换成ByteArrayInputStream
* @param image  图片
* @return ByteArrayInputStream 流
*/
private static ByteArrayInputStream convertImageToStream(BufferedImage image){

ByteArrayInputStream inputStream = null;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
JPEGImageEncoder jpeg = JPEGCodec.createJPEGEncoder(bos);
try {
jpeg.encode(image);
byte[] bts = bos.toByteArray();
inputStream = new ByteArrayInputStream(bts);
} catch (ImageFormatException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return inputStream;
}
}

ValidateAction.action

import java.io.ByteArrayInputStream;
import java.util.Map;

import org.apache.struts2.interceptor.SessionAware;

import com.opensymphony.xwork2.ActionSupport;

public class ValidAction extends ActionSupport implements SessionAware{

//Struts2中Map类型的session
private Map<String, Object> session;
//图片流
private ByteArrayInputStream imageStream;

public String valid(){

<span style="white-space:pre">	</span>//如果开启Hard模式，可以不区分大小写
<span style="white-space:pre">	</span>// String securityCode = ValidateCode.getSecurityCode(4,SecurityCodeLevel.Hard, false).toLowerCase();

//获取默认难度和长度的验证码
String securityCode = ValidateCode.getSecurityCode();
imageStream = ValidateImg.getImageAsInputStream(securityCode);
//放入session中
session.put("SESSION_SECURITY_CODE", securityCode);
return SUCCESS;
}

public void setSession(Map<String, Object> session) {
this.session = session;

}
public ByteArrayInputStream getImageStream() {
return imageStream;
}
public void setImageStream(ByteArrayInputStream imageStream) {
this.imageStream = imageStream;
}
public Map<String, Object> getSession() {
return session;
}

}

struts.xml

<action name="valid" class="com.web.action.ValidAction" method="valid">
<result name="success" type="stream">
<param name="contentType">image/jpeg</param>
<param name="inputName">imageStream</param>
<param name="bufferSize">2048</param>
</result>
</action>

login.jsp

<pre name="code" class="html"><script language="JavaScript" type="text/JavaScript">

function changeImage(){<span style="white-space:pre">	</span>var rom = parseInt(100000000000*Math.random());<span style="white-space:pre">	</span>document.getElementById("imageValid").src="<%=basePath%>valid.action?timeStamp="+rom;}window.onload=function(){<span style="white-space:pre">	</span>var rom = parseInt(100000000000*Math.random());<span style="white-space:pre">	</span>document.getElementById("userName").focus();<span style="white-space:pre">	</span>document.getElementById("imageValid").src="<%=basePath%>valid.action?timeStamp="+rom;<span style="white-space:pre">	</span>$("#fbl").val(document.documentElement.clientHeight);}</script>

<input  name="valid" id="validNum" maxlength="4" class="loginImgNum"/><span> <img src="" width=55 height="37px" style="vertical-align:bottom;border:0px;"  id="imageValid" onclick="changeImage()"/></span>