登录生成随机验证码完整源码分享2017

登录生成随机验证码完整源码分享2017

1.新建一个servlet，路径为servlet/ValidateCodeServlet.java

package common.servlet;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.io.OutputStream;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang3.math.NumberUtils;

import org.apache.commons.lang3.StringUtils;

@SuppressWarnings("serial")

public class ValidateCodeServlet extends HttpServlet {

    public static final String VALIDATE_CODE = "validateCode";

    private int w = 70;

    private int h = 26;

    public ValidateCodeServlet() {

        super();

}

    public void destroy() {

        super.destroy();

}

    public static boolean validate(HttpServletRequest request, String validateCode){

        String code = (String)request.getSession().getAttribute(VALIDATE_CODE);

        return validateCode.toUpperCase().equals(code);

}

    public void doGet(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        String validateCode = request.getParameter(VALIDATE_CODE); // AJAX验证，成功返回true

        if (StringUtils.isNotBlank(validateCode)){

            response.getOutputStream().print(validate(request, validateCode)?"true":"false");

        }else{

            this.doPost(request, response);

}

}

    public void doPost(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        createImage(request,response);

}

    private void createImage(HttpServletRequest request,

            HttpServletResponse response) throws IOException {

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

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

        response.setDateHeader("Expires", 0);

        response.setContentType("image/jpeg");

         //得到参数高，宽，都为数字时，则使用设置高宽，否则使用默认值

        String width = request.getParameter("width");

        String height = request.getParameter("height");

        if (StringUtils.isNumeric(width) && StringUtils.isNumeric(height)) {

            w = NumberUtils.toInt(width);

            h = NumberUtils.toInt(height);

}

        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);

        Graphics g = image.getGraphics();

        // 生成背景

        createBackground(g);

        // 生成字符

        String s = createCharacter(g);

        request.getSession().setAttribute(VALIDATE_CODE, s);

        g.dispose();

        OutputStream out = response.getOutputStream();

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

        out.close();

}

    private Color getRandColor(int fc,int bc) {

        int f = fc;

        int b = bc;

        Random random=new Random();

        if(f>255) {

            f=255;

}

        if(b>255) {

            b=255;

}

        return new Color(f+random.nextInt(b-f),f+random.nextInt(b-f),f+random.nextInt(b-f));

}

    private void createBackground(Graphics g) {

        // 填充背景

        g.setColor(getRandColor(220,250));

        g.fillRect(0, 0, w, h);

        // 加入干扰线条

        for (int i = 0; i < 8; i++) {

            g.setColor(getRandColor(40,150));

            Random random = new Random();

            int x = random.nextInt(w);

            int y = random.nextInt(h);

            int x1 = random.nextInt(w);

            int y1 = random.nextInt(h);

            g.drawLine(x, y, x1, y1);

}

}

    private String createCharacter(Graphics g) {

        char[] codeSeq = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J',

                'K', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',

                'X', 'Y', 'Z', '2', '3', '4', '5', '6', '7', '8', '9' };

        String[] fontTypes = {"Arial","Arial Black","AvantGarde Bk BT","Calibri"};

        Random random = new Random();

        StringBuilder s = new StringBuilder();

        for (int i = 0; i < 4; i++) {

            String r = String.valueOf(codeSeq[random.nextInt(codeSeq.length)]);

g.setColor(new Color(50 + random.nextInt(100), 50 +

random.nextInt(100), 50 + random.nextInt(100)));

            g.setFont(new Font(fontTypes[random.nextInt(fontTypes.length)],Font.BOLD,26));

            g.drawString(r, 15 * i + 5, 19 + random.nextInt(8));

            s.append(r);

}

        return s.toString();

}

}

2.在web.xml配置上述新建的servlet类

<servlet>

<servlet-name>ValidateCodeServlet</servlet-name>

<servlet-class>servlet.ValidateCodeServlet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>ValidateCodeServlet</servlet-name>

<url-pattern>/servlet/validateCodeServlet</url-pattern>

</servlet-mapping>

3.jsp页面代码

<input type="text" />

<img src="${pageContext.request.contextPath}/servlet/validateCodeServlet" onclick="$('.refresh').click();" class="img" /><a href="javascript:" onclick="$('.img').attr('src','${pageContext.request.contextPath}/servlet/validateCodeServlet?'+new Date().getTime());" class="refresh" >看不清</a>