servlet生成图片验证码

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环境
eclipse(2018-12 (4.10.0)),jdk1.8.0_191,tomcat7.0.62
代码

1.SafeCodeUtil.java

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package com.common.utils.safecode;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**	生成指定大小的图片验证码，返回
 * 	并将图片验证码存入session中
 * 	session对象imageCode
 * @author admin
 */
public class SafeCodeUtil {
	public static final String RANDOMCODEKEY = "imageCode";//放到session中的key
    private Random random = new Random();
    //private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生的字符串
    private String randString = "23456789ABCDEFGHJKLMNPRSTWXY";//随机产生的字符串
    
    private int width = 73;//图片宽
    private int height = 28;//图片高
    private int lineSize = 30;//干扰线数量
    private int stringNum = 4;//随机产生字符数量
    /*
     * 	获得字体
     */
    private Font getFont(){
        return new Font("Fixedsys",Font.CENTER_BASELINE,18);
    }
    /*
     * 	获得颜色
     */
    private Color getRandColor(int fc,int bc){
        if(fc > 255) {
			fc = 255;
		}
        if(bc > 255) {
			bc = 255;
		}
        int r = fc + random.nextInt(bc-fc-16);
        int g = fc + random.nextInt(bc-fc-14);
        int b = fc + random.nextInt(bc-fc-18);
        return new Color(r,g,b);
    }
    /**
     * 	生成随机图片
     */
    public void getRandcode(HttpServletRequest request,
            HttpServletResponse response) {
        HttpSession session = request.getSession();
        //BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
        BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_BGR);
        Graphics g = image.getGraphics();//产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
        g.fillRect(0, 0, width, height);
        g.setFont(new Font("Times New Roman",Font.ROMAN_BASELINE,18));
        g.setColor(getRandColor(110, 133));
        //绘制干扰线
        for(int i=0;i<=lineSize;i++){
            drowLine(g);
        }
        //绘制随机字符
        String randomString = "";
        for(int i=1;i<=stringNum;i++){
            randomString=drowString(g,randomString,i);
        }
        session.removeAttribute(RANDOMCODEKEY);
        session.setAttribute(RANDOMCODEKEY, randomString);
        g.dispose();
        try {
            ImageIO.write(image, "JPEG", response.getOutputStream());//将内存中的图片通过流动形式输出到客户端
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    /*
     * 	绘制字符串
     */
    private String drowString(Graphics g,String randomString,int i){
        g.setFont(getFont());
        g.setColor(new Color(random.nextInt(101),random.nextInt(111),random.nextInt(121)));
        String rand = String.valueOf(getRandomString(random.nextInt(randString.length())));
        randomString +=rand;
        g.translate(random.nextInt(3), random.nextInt(3));
        g.drawString(rand, 13*i, 16);
        return randomString;
    }
    /*
     * 	绘制干扰线
     */
    private void drowLine(Graphics g){
        int x = random.nextInt(width);
        int y = random.nextInt(height);
        int xl = random.nextInt(13);
        int yl = random.nextInt(15);
        g.drawLine(x, y, x+xl, y+yl);
    }
    /*
     * 	获取随机的字符
     */
    public String getRandomString(int num){
        return String.valueOf(randString.charAt(num));
    }
}

2.SafeCode.java
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package com.common.utils.safecode;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**生成验证码**/
public class SafeCode extends HttpServlet {
	private static final long SERIAL_VERSION_UID = 1L;
	@Override
	public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("image/jpeg");// 设置相应类型,告诉浏览器输出的内容为图片
		response.setHeader("Pragma", "No-cache");// 设置响应头信息，告诉浏览器不要缓存此内容
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expire", 0);
		SafeCodeUtil randomValidateCode = new SafeCodeUtil();
		try {
			randomValidateCode.getRandcode(request, response);// 输出图片方法
			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

3.GenerateImageCode.java
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package com.common.utils.safecode;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.common.utils.safecode.SafeCodeUtil;
/**
 * @author wangming
 * 	生成随机验证码
 * Servlet implementation class GenerateImageCode
 */
@WebServlet("/GenerateImageCode")
public class GenerateImageCode extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public GenerateImageCode() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doPost(request, response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.setContentType("image/jpeg");// 设置相应类型,告诉浏览器输出的内容为图片
		response.setHeader("Pragma", "No-cache");// 设置响应头信息，告诉浏览器不要缓存此内容
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expire", 0);
		SafeCodeUtil randomValidateCode = new SafeCodeUtil();
		try {
			randomValidateCode.getRandcode(request, response);// 输出图片方法
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

}

4.web.xml内webapps标签添加如下代码
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<servlet>
   <servlet-name>SafeCode</servlet-name>
   <servlet-class>com.common.utils.safecode.GenerateImageCode</servlet-class>
</servlet>
 <servlet-mapping>
    <servlet-name>SafeCode</servlet-name>
    <url-pattern>/SafeCode</url-pattern>
 </servlet-mapping>

访问路径与结果
http://localhost:8888/servletImgVerificationr/SafeCode，结果如下：

克隆地址:
https://github.com/syxiaowanzi/servlet-utils.git

本文标题:servlet生成图片验证码

文章作者:wangming

发布时间:2019年01月19日 - 00:29:57

最后更新:2019年01月22日 - 23:39:08

原始链接:https://syxiaowanzi.github.io/2019/01/19/servlet生成图片验证码/

许可协议: 署名-非商业性使用-禁止演绎 4.0 国际 转载请保留原文链接及作者。

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