/** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("image/jpeg"); ServletOutputStream sos=response.getOutputStream();
//设置图形上下文环境字体 gc.setFont(new Font("Times New Roman",Font.PLAIN,18));
//随机产生200条干扰线条,使图像中的认证码不易被其他分析程序探测到 gc.setColor(getRandColor(160, 200)); for(int i=0;i<200;i++){ int x1=r.nextInt(width); int y1=r.nextInt(height); int x2=r.nextInt(15); int y2=r.nextInt(15); gc.drawLine(x1, y1, x1+x2, y1+y2); }
//随机产生100个干扰点,使图像中的验证码不易被其他分析程序探测到 gc.setColor(getRandColor(120, 240)); for(int i=0;i<100;i++){ int x=r.nextInt(width); int y=r.nextInt(height); gc.drawOval(x, y, 0, 0); }
private Color getRandColor(int fc,int bc){ Random r=new Random(); if(fc>255) fc=255; if(bc>255) bc=255; int red=fc+r.nextInt(bc-fc);//红 int green=fc+r.nextInt(bc-fc);//绿 int blue=fc+r.nextInt(bc-fc);//蓝 return new Color(red,green,blue); }}
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;@SuppressWarnings("serial")
public class RandomIMG extends HttpServlet { private int width=50;//图像宽度
private int height=20;//图像高度
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("image/jpeg");
ServletOutputStream sos=response.getOutputStream();
Random r=new Random();
//在内存中创建图像,宽度为width,高度为height
BufferedImage pic=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
//获取图形上下文环境
Graphics gc=pic.getGraphics();
//设定背景色并进行填充
gc.setColor(getRandColor(200, 250));
gc.fillRect(0, 0, width, height);
//设置图形上下文环境字体
gc.setFont(new Font("Times New Roman",Font.PLAIN,18));
//随机产生200条干扰线条,使图像中的认证码不易被其他分析程序探测到
gc.setColor(getRandColor(160, 200));
for(int i=0;i<200;i++){
int x1=r.nextInt(width);
int y1=r.nextInt(height);
int x2=r.nextInt(15);
int y2=r.nextInt(15);
gc.drawLine(x1, y1, x1+x2, y1+y2);
}
//随机产生100个干扰点,使图像中的验证码不易被其他分析程序探测到
gc.setColor(getRandColor(120, 240));
for(int i=0;i<100;i++){
int x=r.nextInt(width);
int y=r.nextInt(height);
gc.drawOval(x, y, 0, 0);
}
//随机产生4个数字的验证码
String rs="";
String rn="";
for(int i=0;i<4;i++){
rn=String.valueOf(r.nextInt(10));
rs+=rn;
gc.setColor(new Color(20+r.nextInt(110),20+r.nextInt(110),20+r.nextInt(110)));
gc.drawString(rn, 13*i+1, 16);
}
//释放图形上下文环境
gc.dispose();
// if(request.getSession().getAttribute("hk_verify")!=null || request.getSession().getAttribute("hk_verify")!=""){
// request.getSession().setAttribute("hk_verify", null);
// request.getSession().removeAttribute("hk_verify");
// }
//将认证码rs存放到session中共享
request.getSession().setAttribute("seccode", rs);
//输出生成后的验证码图像到页面
ImageIO.write(pic, "JPEG", sos);
sos.flush();
sos.close();
}
private Color getRandColor(int fc,int bc){
Random r=new Random();
if(fc>255) fc=255;
if(bc>255) bc=255;
int red=fc+r.nextInt(bc-fc);//红
int green=fc+r.nextInt(bc-fc);//绿
int blue=fc+r.nextInt(bc-fc);//蓝
return new Color(red,green,blue);
}}
如何Servlet中输出图片呢。
重点在这一段:...
//输出生成后的验证码图像到页面
ImageIO.write(pic, "JPEG", sos);
sos.flush();
sos.close();
...