java實現登錄驗證碼

本文實例為大家分享了java實現登錄驗證碼的具體代碼，供大家參考，具體內容如下

1、ValidateCode.java

 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 org.springframework.stereotype.Service;/** * 登錄驗證碼* */public class ValidateCode { /** * 得到驗證碼圖片* @param out * @param number 驗證數字* @throws ServletException * @throws IOException */ public void getImage(OutputStream out,String number) throws ServletException, IOException { //0.創建空白圖片BufferedImage image=new BufferedImage(100,30,BufferedImage.TYPE_INT_RGB); //1.獲取圖片畫筆Graphics g = image.getGraphics(); Random r=new Random(); //2.設置畫筆顏色(Random類中的nextInt(n)返回一個大於等於0，小於n的隨機數) g.setColor(new Color(r.nextInt(255),r.nextInt(255), r.nextInt(255))); //3.繪製矩形的背景g.fillRect(0, 0, 100, 30); //4.調用自定義的方法，獲取長度為4的字母數字組合的字符串g.setColor(new Color(0,0,0)); g.setFont(new Font(null,Font.BOLD,24)); //5.設置顏色字體後，繪製字符串（x/y,最左邊字符所處的位置） g.drawString(number, 20, 24); //6.繪製8條干擾線(alpha表示透明度) for(int i=0;i<8;i++){ g.setColor(new Color(r.nextInt(255),r.nextInt(255), r.nextInt(255),r.nextInt(255))); g.drawLine(r.nextInt(100), r.nextInt(30), r.nextInt(100), r.nextInt(30)); } ImageIO.write(image, "jpeg", out); } //自定義方法，獲取長度為size的字母數字組合的字符串public String getNumber(int size){ String str="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; String number=""; Random r = new Random(); for(int i=0;i<size;i++){ number+=str.charAt(r.nextInt(str.length())); } return number; }}

2、Controller

 @RequestMapping(value = "/check",method={RequestMethod.GET}) @ResponseBody public void check(HttpServletRequest req) { try { HttpServletResponse response = this.getResponse(); response.setContentType("application/octet-stream"); response.addHeader("Content-Disposition", "attachment;filename=" + "vcode.jpeg"); String number = validateCode.getNumber(4); validateCode.getImage(response.getOutputStream(),number); } catch (Exception e) { } }

3、html

 <img src="http://127.0.0.1:8080/test/check">

效果圖

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。