后台生成一个随机的英文与数字组合的验证码
【摘要】
@CrossOrigin(origins = "http://192.168.10.110:2501",maxAge = 3600,allowCredentials = "true")
@RestCont...
@CrossOrigin(origins = "http://192.168.10.110:2501",maxAge = 3600,allowCredentials = "true")
@RestController
@RequestMapping("/checkCode")
public class CheckCode extends HttpServlet {
@PostMapping("/check")
public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
response.setHeader("Access-Control-Allow-Origin",request.getHeader("Origin"));//支持跨域请求
response.setHeader("Access-Control-Allow-Methods", "*");
response.setHeader("Access-Control-Allow-Credentials", "true");//是否支持cookie跨域
//response.setHeader("Access-Control-Allow-Headers", "Authorization,Origin, X-Requested-With, Content-Type, Accept,Access-Token");
response.setHeader("Access-Control-Allow-Headers", "Content-Type, Access-Control-Allow-Headers, Authorization, X-Requested-With");
//服务器通知浏览器不要缓存
response.setHeader("Pragma","no-cache");
response.setHeader("Cache-Control","no-cache");
response.setHeader("expires","0");
response.setDateHeader("Expires",0);
//在内存中创建一个长80,宽30的图片,默认黑色背景
//参数一:长
//参数二:宽
//参数三:颜色
int width = 80;
int height = 30;
BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
//获取画笔
Graphics g = image.getGraphics();
//设置画笔颜色为灰色
g.setColor(Color.GRAY);
//填充图片
g.fillRect(0,0, width,height);
//产生4个随机验证码,12Ey
String checkCode = getCheckCode();
//将验证码放入HttpSession中
request.getSession().setAttribute("CHECKCODE_SERVER",checkCode);
HttpSession session = request.getSession();
System.out.println(session.getId());
HttpPost httpPost=new HttpPost();
httpPost.setHeader("SessionId",session.getId());
//设置画笔颜色为黄色
g.setColor(Color.YELLOW);
//设置字体的小大
g.setFont(new Font("黑体",Font.BOLD,24));
//向图片上写入验证码
g.drawString(checkCode,15,25);
//将内存中的图片输出到浏览器
//参数一:图片对象
//参数二:图片的格式,如PNG,JPG,GIF
//参数三:图片输出到哪里去
ImageIO.write(image,"PNG",response.getOutputStream());
}
/**
* 产生4位随机字符串
*/
private String getCheckCode() {
String base = "0123456789ABCDEFGabcdefg";
int size = base.length();
Random r = new Random();
StringBuffer sb = new StringBuffer();
for(int i=1;i<=4;i++){
//产生0到size-1的随机值
int index = r.nextInt(size);
//在base字符串中获取下标为index的字符
char c = base.charAt(index);
//将c放入到StringBuffer中去
sb.append(c);
}
return sb.toString();
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request,response);
}
}
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文章来源: baidaguo.blog.csdn.net,作者:白大锅,版权归原作者所有,如需转载,请联系作者。
原文链接:baidaguo.blog.csdn.net/article/details/117983778
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