【实现】用户认证：验证码

[toc]

工具类

java

package hw.utils.common;

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.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;

/**
 * 生成验证码
 */
public class ValidateCode {
    private int width = 70;
    private int height = 35;
    private Random random = new Random();
    private StringBuilder code = new StringBuilder(4);
    //创建一张有背景色的图片
    private BufferedImage createImage(){
        BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics g = img.getGraphics();
        g.setColor(new Color(240,240,240));
        g.fillRect(0, 0, width, height);
        return img;
    }

    //此方法必须在getImage方法之后调用
    private String getCode(){
        return this.code.toString();
    }
    //获得验证码图片
    private BufferedImage getImage(){
        //获得有背景色的图片
        BufferedImage img = this.createImage();
        //绘制字母：颜色随机，字体大小，字体，字号随机，字母随机
        Graphics g = img.getGraphics();
        for(int i=0;i<4;i++){
            String str = this.getRandomString();//得到随机字母
            this.code.append(str);
            g.setFont(this.getRandomFont());//得到随机字体
            g.setColor(this.getRandomColor());//得到随机颜色
            g.drawString(str, width/4*i, height-5);
        }
        //绘制干扰线
        this.drawLines(img);
        return img;
    }

    //绘制干扰线
    private void drawLines(BufferedImage image){
        Graphics g = image.getGraphics();
        g.setColor(Color.BLACK);
        for(int i=0;i<5;i++){
            int x1 = random.nextInt(this.width);
            int y1 = random.nextInt(this.height);
            int x2 = random.nextInt(this.width);
            int y2 = random.nextInt(this.height);
            g.drawLine(x1, y1, x2, y2);
        }
    }
    private Color getRandomColor() {
        int r = this.random.nextInt(256);//0-255
        int g = this.random.nextInt(256);
        int b = this.random.nextInt(256);
        return new Color(r, g, b);
    }

    private String[] fontNames = {"宋体","华文楷体","黑体","华文新魏","华文隶书","微软雅黑","楷体_GB2312"};
    private int[] fontSizes = {24,25,26,27,28};
    private Font getRandomFont() {
        int index = this.random.nextInt(this.fontNames.length);//0-6
        String name = this.fontNames[index];
        int style = this.random.nextInt(4);
        index = this.random.nextInt(this.fontSizes.length);
        int size = this.fontSizes[index];
        return new Font(name, style, size);
    }

    private String codes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
    private String getRandomString() {
        int index = random.nextInt(this.codes.length());
        return this.codes.charAt(index)+"";
    }


    //保存图片
    private void saveImage(BufferedImage im,OutputStream output) throws IOException{
        ImageIO.write(im, "JPEG", output);
    }

    /**
     * 将图片输出到页面，并返回验证码
     */
    public static String outputImage(HttpServletResponse response) throws Exception{

        response.setContentType("image/jpeg");
        ServletOutputStream servletOutputStream = response.getOutputStream();
        ValidateCode v = new ValidateCode();
        BufferedImage img = v.getImage();
        //System.out.println(v.getCode());//getCode必须在getImage后面
        v.saveImage(img,servletOutputStream);
        servletOutputStream.flush();
        servletOutputStream.close();

        return v.getCode();

    }
    /*
    public static void main(String[] args) throws Exception {

        //使用说明
        ValidateCode v = new ValidateCode();
        BufferedImage img = v.getImage();
        System.out.println(v.getCode());//getCode必须在getImage后面
        ValidateCode.saveImage(img, new FileOutputStream("/machine/a.jpg"));

    }

    */

}

验证码输出到页面

Code

@RequestMapping("/validatecode")
public String validatecode(HttpServletResponse response,
                       HttpSession session) throws Exception {

    //向页面输出验证码，并得到验证码
    String validateCode = ValidateCode.outputImage(response);
    //把验证码放到session域
    session.setAttribute("validateCode",validateCode);

    return "/base/login";

}

页面请求验证码

Code

<TR>
	<TD>验证码：</TD>
	<TD>
	    <input id="randomcode" name="randomcode" size="8" /> 
	    <img id="randomcode_img" src="${baseurl}login/validatecode.action" alt=""
		width="56" height="20" align='absMiddle' /> <a
		href=javascript:randomcode_refresh()>刷新</a></TD>
</TR>

Code

//刷新验证码
//实现思路，重新给图片的src赋值，后边加时间，防止缓存 
function randomcode_refresh() {
	$("#randomcode_img").attr('src',
			'${baseurl}login/validatecode.action?time' + new Date().getTime());
}

认证校验

Code

//登录表单提交
@RequestMapping("/loginsubmit")
public String loginformsubmit(HttpSession session) throws Exception {

    //从session获取验证码
    String validateCode_session = (String)session.getAttribute("validateCode");
    
    //...进行登录校验
    
    return "/base/first";//首页

}