session技术、完成验证码的校验--会话(页码CK2)

落日映苍穹つ 2023-07-17 15:34 12阅读 0赞

![在这里插入图片描述][20200322192248865.png]  
![在这里插入图片描述][20200322192640964.png]  
![在这里插入图片描述][20200322195006974.png]  
![在这里插入图片描述][20200322195651948.png]

package cn.aynortechnology.session;
    
    import java.io.IOException;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    public class SessionServlet1 extends HttpServlet {
    
    	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		//创建属于该客户端(会话)的私有的session区域
    		/**
    		 * 该方法会判断该客户端是否在服务器端已经存在session 
    		 * 如果该客户端在此服务器不存在session 那么就会创建一个新的session对象
    		 * 如果该客户端在此服务器存在session 那么已经存在的该session返回
    		 */
    		HttpSession session = request.getSession();
    		String id = session.getId();//该session对象的编号id
    		response.getWriter().write("JSESSIONID:"+id);
    	}
    
    	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		doGet(request, response);
    	}
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTIyODQ1_size_16_color_FFFFFF_t_70]  
![在这里插入图片描述][20200322201002106.png]  
**验证码校验**  
生成验证码

package cn.aynortechnology.checkimg;
    
    import java.awt.Color;
    import java.awt.Font;
    import java.awt.Graphics;
    import java.awt.Graphics2D;
    import java.awt.image.BufferedImage;
    import java.io.BufferedReader;
    import java.io.FileReader;
    import java.io.IOException;
    import java.util.ArrayList;
    import java.util.List;
    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;
     
    /**
     * 验证码生成程序
     * 
     * 
     * 
     */
    public class CheckImgServlet extends HttpServlet {
     
    	// 集合中保存所有成语
    	private List<String> words = new ArrayList<String>();
     
    	@Override
    	public void init() throws ServletException {
    		// 初始化阶段，读取new_words.txt
    		// web工程中读取 文件，必须使用绝对磁盘路径
    		String path = getServletContext().getRealPath("/WEB-INF/new_words.txt");
    		try {
    			BufferedReader reader = new BufferedReader(new FileReader(path));
    			String line;
    			while ((line = reader.readLine()) != null) {
    				words.add(line);
    			}
    			reader.close();
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
     
    	public void doGet(HttpServletRequest request, HttpServletResponse response)
    			throws ServletException, IOException {
    		// 禁止缓存
    		// response.setHeader("Cache-Control", "no-cache");
    		// response.setHeader("Pragma", "no-cache");
    		// response.setDateHeader("Expires", -1);
     
    		int width = 120;
    		int height = 30;
     
    		// 步骤一 绘制一张内存中图片
    		BufferedImage bufferedImage = new BufferedImage(width, height,
    				BufferedImage.TYPE_INT_RGB);
     
    		// 步骤二 图片绘制背景颜色 ---通过绘图对象
    		Graphics graphics = bufferedImage.getGraphics();// 得到画图对象 --- 画笔
    		// 绘制任何图形之前 都必须指定一个颜色
    		graphics.setColor(getRandColor(200, 250));
    		graphics.fillRect(0, 0, width, height);
     
    		// 步骤三 绘制边框
    		graphics.setColor(Color.WHITE);
    		graphics.drawRect(0, 0, width - 1, height - 1);
     
    		// 步骤四 四个随机数字
    		Graphics2D graphics2d = (Graphics2D) graphics;
    		// 设置输出字体
    		graphics2d.setFont(new Font("宋体", Font.BOLD, 18));
     
    		Random random = new Random();// 生成随机数
    		int index = random.nextInt(words.size());
    		String word = words.get(index);// 获得成语
     
    		// 定义x坐标
    		int x = 10;
    		for (int i = 0; i < word.length(); i++) {
    			// 随机颜色
    			graphics2d.setColor(new Color(20 + random.nextInt(110), 20 + random
    					.nextInt(110), 20 + random.nextInt(110)));
    			// 旋转 -30 --- 30度
    			int jiaodu = random.nextInt(60) - 30;
    			// 换算弧度
    			double theta = jiaodu * Math.PI / 180;
     
    			// 获得字母数字
    			char c = word.charAt(i);
     
    			// 将c 输出到图片
    			graphics2d.rotate(theta, x, 20);
    			graphics2d.drawString(String.valueOf(c), x, 20);
    			graphics2d.rotate(-theta, x, 20);
    			x += 30;
    		}
     
    		// 将验证码内容保存session
    		request.getSession().setAttribute("checkcode_session", word);
     
    		// 步骤五 绘制干扰线
    		graphics.setColor(getRandColor(160, 200));
    		int x1;
    		int x2;
    		int y1;
    		int y2;
    		for (int i = 0; i < 30; i++) {
    			x1 = random.nextInt(width);
    			x2 = random.nextInt(12);
    			y1 = random.nextInt(height);
    			y2 = random.nextInt(12);
    			graphics.drawLine(x1, y1, x1 + x2, x2 + y2);
    		}
     
    		// 将上面图片输出到浏览器 ImageIO
    		graphics.dispose();// 释放资源
    		ImageIO.write(bufferedImage, "jpg", response.getOutputStream());
     
    	}
     
    	public void doPost(HttpServletRequest request, HttpServletResponse response)
    			throws ServletException, IOException {
    		doGet(request, response);
    	}
     
    	/**
    	 * 取其某一范围的color
    	 * 
    	 * @param fc
    	 *            int 范围参数1
    	 * @param bc
    	 *            int 范围参数2
    	 * @return Color
    	 */
    	private Color getRandColor(int fc, int bc) {
    		// 取其随机颜色
    		Random random = new Random();
    		if (fc > 255) {
    			fc = 255;
    		}
    		if (bc > 255) {
    			bc = 255;
    		}
    		int r = fc + random.nextInt(bc - fc);
    		int g = fc + random.nextInt(bc - fc);
    		int b = fc + random.nextInt(bc - fc);
    		return new Color(r, g, b);
    	}
     
    }

index

<!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    
    <script type="text/javascript">
    	window.onload = function(){
    		
    	}
    	
    	function changeImg(obj){
    		obj.src = "/WEB16/checkImg?time="+new Date().getTime();
    	}
    </script>
    
    </head>
    <body>
    	<div>
    		<%=request.setAttribute("loginInfo")==null?"":request.getAttribute("loginInfo")%>
    	</div>
    	<form action="/WEB16/login" method="post">
    		用户名：<input type="text" name="username"><br/>
    		密码：<input type="password" name="password"><br/>
    		验证码：<input type="text" name="checkCode"><img onclick="changeImg(this)" src="/WEB16/checkImg">
    		<div><%=request.getAttribute("loginInfo")==null?"":request.getAttribute("loginInfo")%></div><br/>
    		<input type="submit" value="登录"><br/>
    	</form>
    </body>
    </html>

校验验证码

package cn.aynortechnology.login;
    
    import java.io.IOException;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    public class LoginServlet extends HttpServlet {
    
    	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		
    		request.setCharacterEncoding("UTF-8");
    		//验证码的校验
    		//获得页面输入的验证码
    		String checkCode_client = request.getParameter("checkCode");
    		//获得生成图片的文字的验证码
    		Object checkCode_session = request.getSession().getAttribute("checkcode_session");
    		//比对页面的和生成图片的文字的验证码是否一致
    		if(!checkCode_session.equals(checkCode_client)) {
    			request.setAttribute("loginInfo","验证码错误");
    			request.getRequestDispatcher("/login.jsp").forward(request, response);
    			return;
    		}
    		//获得页面的用户名和密码进行数据校验
    		
    		
    	}
    
    	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		doGet(request, response);
    	}
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTIyODQ1_size_16_color_FFFFFF_t_70 1]  
[(页码CK1)cookie的创建、发送与接收–会话][CK1_cookie]  
[(页码CK2)session技术、完成验证码的校验–会话][CK2_session]

[20200322192248865.png]: /images/20230528/a7f0f0abf30d4527a8f9a6550c0bd4e6.png
[20200322192640964.png]: /images/20230528/f3cc561021ff4b1ab98ae38730c7693c.png
[20200322195006974.png]: /images/20230528/073709419aa548f78c2a950b99ac9d54.png
[20200322195651948.png]: /images/20230528/9f0bdf0e2201438facbfa91c46eb0992.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTIyODQ1_size_16_color_FFFFFF_t_70]: /images/20230528/55be2187b16c48d693efad159051a427.png
[20200322201002106.png]: /images/20230528/07739a6cf4bd479cb367d49b7c8c42d7.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwOTIyODQ1_size_16_color_FFFFFF_t_70 1]: /images/20230528/1f90151850754ccebf377dbb72666663.png
[CK1_cookie]: https://blog.csdn.net/qq_40922845/article/details/105029485
[CK2_session]: https://blog.csdn.net/qq_40922845/article/details/105033480