servlet動態生成驗證碼
阿新 • • 發佈：2020-12-22
HTML部分：
<b>驗證碼：</b> <div class="inptinfo"> <input name="checkCode" class="inpt" style="width: 50%" placeholder="請輸入驗證碼!" type="text" id="checkCode" title="驗證碼區分大小寫" size="8" maxlength="4" /> <img src="localhost:8080/test/PictureCheckCode" id="CreateCheckCode" align="top" style="width:80px; height: 2.5rem;"> <a href="javascript:;" onclick="myReload()"><br>看不清，換一個</a> </div>
PictureCheckCode類：
import java.awt.*; import java.awt.geom.*; import java.awt.image.*; import java.io.*; import java.util.*; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import javax.imageio.ImageIO; public class PictureCheckCode extends HttpServlet{ private static final long serialVersionUID = 1L; public PictureCheckCode() { super(); } public void destroy() { super.destroy(); } public void init() throws ServletException { super.init(); } /*該方法主要作用是獲得隨機生成的顏色*/ public Color getRandColor(int s,int e){ Random random=new Random (); if(s>255) s=255; if(e>255) e=255; int r,g,b; r=s+random.nextInt(e-s); //隨機生成RGB顏色中的r值 g=s+random.nextInt(e-s); //隨機生成RGB顏色中的g值 b=s+random.nextInt(e-s); //隨機生成RGB顏色中的b值 return new Color(r,g,b); } @Override public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //設定不快取圖片 response.setHeader("Pragma", "No-cache"); response.setHeader("Cache-Control", "No-cache"); response.setDateHeader("Expires", 0); //指定生成的響應圖片,一定不能缺少這句話,否則錯誤. response.setContentType("image/jpeg"); int width=86,height=22; //指定生成驗證碼的寬度和高度 BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); //建立BufferedImage物件,其作用相當於一圖片 Graphics g=image.getGraphics(); //建立Graphics物件,其作用相當於畫筆 Graphics2D g2d=(Graphics2D)g; //建立Grapchics2D物件 Random random=new Random(); Font mfont=new Font("宋體",Font.BOLD,16); //定義字型樣式 g.setColor(getRandColor(200,250)); g.fillRect(0, 0, width, height); //繪製背景 g.setFont(mfont); //設定字型 g.setColor(getRandColor(180,200)); //繪製100條顏色和位置全部為隨機產生的線條,該線條為2f for(int i=0;i<100;i++){ int x=random.nextInt(width-1); int y=random.nextInt(height-1); int x1=random.nextInt(6)+1; int y1=random.nextInt(12)+1; BasicStroke bs=new BasicStroke(2f,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL); //定製線條樣式 Line2D line=new Line2D.Double(x,y,x+x1,y+y1); g2d.setStroke(bs); g2d.draw(line); //繪製直線 } //輸出由英文，數字，和中文隨機組成的驗證文字，具體的組合方式根據生成隨機數確定。 String sRand=""; String ctmp=""; int itmp=0; //制定輸出的驗證碼為四位 for(int i=0;i<4;i++){ switch(random.nextInt(2)){ case 1: //生成A-Z的字母 itmp=random.nextInt(26)+65; ctmp=String.valueOf((char)itmp); break; case 2: //生成漢字 String[] rBase={"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"}; //生成第一位區碼 int r1=random.nextInt(3)+11; String str_r1=rBase[r1]; //生成第二位區碼 int r2; if(r1==13){ r2=random.nextInt(7); }else{ r2=random.nextInt(16); } String str_r2=rBase[r2]; //生成第一位位碼 int r3=random.nextInt(6)+10; String str_r3=rBase[r3]; //生成第二位位碼 int r4; if(r3==10){ r4=random.nextInt(15)+1; }else if(r3==15){ r4=random.nextInt(15); }else{ r4=random.nextInt(16); } String str_r4=rBase[r4]; //將生成的機內碼轉換為漢字 byte[] bytes=new byte[2]; //將生成的區碼儲存到位元組陣列的第一個元素中 String str_12=str_r1+str_r2; int tempLow=Integer.parseInt(str_12, 16); bytes[0]=(byte) tempLow; //將生成的位碼儲存到位元組陣列的第二個元素中 String str_34=str_r3+str_r4; int tempHigh=Integer.parseInt(str_34, 16); bytes[1]=(byte)tempHigh; ctmp=new String(bytes); break; default: itmp=random.nextInt(10)+48; ctmp=String.valueOf((char)itmp); break; } sRand+=ctmp; Color color=new Color(20+random.nextInt(110),20+random.nextInt(110),random.nextInt(110)); g.setColor(color); //將生成的隨機數進行隨機縮放並旋轉制定角度 PS.建議不要對文字進行縮放與旋轉,因為這樣圖片可能不正常顯示 /*將文字旋轉制定角度*/ Graphics2D g2d_word=(Graphics2D)g; AffineTransform trans=new AffineTransform(); trans.rotate((45)*3.14/180,15*i+8,7); /*縮放文字*/ float scaleSize=random.nextFloat()+0.8f; if(scaleSize>1f) scaleSize=1f; trans.scale(scaleSize, scaleSize); g2d_word.setTransform(trans); g.drawString(ctmp, 15*i+18, 6); } HttpSession session=request.getSession(true); session.setAttribute("randCheckCode", sRand); g.dispose(); //釋放g所佔用的系統資源 ImageIO.write(image,"JPEG",response.getOutputStream()); //輸出圖片 } }
java方法驗證：
//亂碼 this.getResponse().setContentType("text/html; charset=UTF-8 " ); PrintWriter out = this.getResponse().getWriter(); //驗證碼 System.out.println(getSession().getAttribute("randCheckCode")); System.out.println("原來的"+checkCode); if(((checkCode.toUpperCase()).equals(((String)getSession().getAttribute("randCheckCode")).toUpperCase()))) { this.getRequest().setAttribute("parafresh", true); this.getRequest().setAttribute("returnMessage", "驗證碼有誤……"); return "refresh"; }
servlet需要配置web.xml
<!-- 二維碼 -->
<servlet>
<servlet-name>PictureCheckCode</servlet-name>
<servlet-class>PictureCheckCode路徑</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>PictureCheckCode</servlet-name>
<url-pattern>/PictureCheckCode</url-pattern>
</servlet-mapping>效果展示
