javaweb验证码的生成与使用

package com.zg.sxsh.serviceImpl;

import com.zg.sxsh.service.IVerificationCodeImage;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

public class VerificationCodeImage implements IVerificationCodeImage {
    //ASCII  0-9 48-57 A-Z 65-90 a-z 97-122
    static int[] asciis=codeASCII();
    /**
     * 把数字与字母的ASCII码存入int[]中
     * @return int[]
     */
    static int[] codeASCII(){
        int[] asciis=new int[62];
        int ascii=48;
        for (int i=0;i<10;i++){
            asciis[i]=ascii;
            ascii++;
        }
        ascii=65;
        for (int i=10;i<36;i++){
            asciis[i]=ascii;
            ascii++;
        }
        ascii=97;
        for (int i=36;i<62;i++){
            asciis[i]=ascii;
            ascii++;
        }
        return asciis;
    }

    /**
     * 生成一串字符串
     * @param codeLength 字符串长度
     * @param isNum 字符串是否有数字
     * @param isABC 字符串是否有字母
     * @return
     */
    @Override
    public String randomVerificationCode(int codeLength, boolean isNum, boolean isABC) {
        String verificationCode="";
        int index=0;
        for(int i=0;i<codeLength;i++){
            if (isNum&isABC){
                index=randomNum(0,62);
            }
            else if(isNum){
                index=randomNum(0,10);
            }
            else if (isABC){
                index=randomNum(10,62);
            }
            verificationCode+=String.valueOf((char) asciis[index]);
        }
        return verificationCode;
    }

    /**
     * 返回一个[minNum,maxNum)的随机数
     * @param minNum 最小数
     * @param maxNum 最大数
     * @return 返回一个字符串
     */
    private int randomNum(int minNum,int maxNum){
        Random random=new Random();
        return random.nextInt(maxNum)+minNum;
    }

    private static final int IMAGE_WIDTH=100;
    private static final int IMAGE_HEIGHT=42;

    /**
     * 生成验证码图片缓存
     * @param verificationCode 验证码字符串
     * @return 图像缓存
     */
    @Override
    public BufferedImage createVerificationCodeImage(String verificationCode){
        //定义图像buffer
        BufferedImage bufferedImage=new BufferedImage(IMAGE_WIDTH,IMAGE_HEIGHT,BufferedImage.TYPE_INT_RGB);
        Graphics graphics=bufferedImage.getGraphics();
        Color color=Color.white;
        //设置画笔颜色
        graphics.setColor(color);
        //设置图像形状和大小
        graphics.fillRect(0,0,IMAGE_WIDTH,IMAGE_HEIGHT);

        //设置字体
        Font font =new Font("微软雅黑",Font.BOLD,30);
        graphics.setFont(font);
        //设置画笔颜色
        graphics.setColor(Color.black);
        //绘制文字
        graphics.drawString(verificationCode,10,31);
        //Graphics转换成Graphics2D
        Graphics2D graphics2D=(Graphics2D)graphics;
        //设置画笔粗细
        graphics2D.setStroke(new BasicStroke(2));
        //设置八个点
        Point[] points=new Point[8];
        for (int i=0;i<4;i++){
            points[i]=new Point();
            points[i].x=1;
            points[i].y=randomNum(1,IMAGE_HEIGHT);
        }
        for (int i=4;i<8;i++){
            points[i]=new Point();
            points[i].x=IMAGE_WIDTH-1;
            points[i].y=randomNum(1,IMAGE_HEIGHT);
        }
        System.out.println(points);
        //根据生成的八个点，画4条干扰线
        for (int i=0;i<4;i++){
            graphics2D.drawLine(points[i].x,points[i].y,points[i+4].x,points[i+4].y);
        }
        return bufferedImage;
    }
}

package com.zg.sxsh.action;

import com.opensymphony.xwork2.ActionSupport;
import com.zg.sxsh.serviceImpl.VerificationCodeImage;
import org.apache.struts2.ServletActionContext;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;

public class VerificationCodeAction extends ActionSupport {

    private ByteArrayInputStream inputStream;

    public ByteArrayInputStream getInputStream() {
        return inputStream;
    }

    /**
     * 把图片缓存转成Stream
     * @return
     * @throws Exception
     */
    @Override
    public String execute() throws Exception {
        //实例化验证码图片生成类
        VerificationCodeImage codeImage=new VerificationCodeImage();
        //生成验证码
        String code=codeImage.randomVerificationCode(4,true,true);
        //获取request
        HttpServletRequest request= ServletActionContext.getRequest();
        //获取Session
        HttpSession session=request.getSession();
        //把验证码存入session
        session.setAttribute("code",code);
        //获取图片缓存
        BufferedImage image= codeImage.createVerificationCodeImage(code);
        // 创建输出流
        ByteArrayOutputStream outputStream=new ByteArrayOutputStream();
        //把图片缓存写入输出流
        ImageIO.write(image,"jpg",outputStream);
        //把图片输出流赋值给输入流
        inputStream=new ByteArrayInputStream(outputStream.toByteArray());
        //关闭输出/输入流
        outputStream.close();
        inputStream.close();

        return SUCCESS;
    }
}

        <action name="verification_code" method="execute" class="com.zg.sxsh.action.VerificationCodeAction">
            <result name="success" type="stream">
                <param name="contentType">image/jpg</param>
                <param name="inputName">inputStream</param>
            </result>
        </action>

<img src="/verification_code" onClick="this.src='verification_code?timestamp='+Date.now()" alt="验证码">