请求转发_综合

<html>
<%@page pageEncoding="utf-8" %>
<body>
<h2>登录!</h2>
<%--<form action="RequestTest" enctype="multipart/form-data" method="get"><input type="submit" name="upload" value="上传"/></form>--%><form action="RequestTest" method="get">用户名：<input type="text" name="username"><br>密  码：<input type="password" name="password"><br>爱好：<input type="checkbox" name="hobbys" value="女孩">女孩<input type="checkbox" name="hobbys" value="代码">代码<input type="checkbox" name="hobbys" value="唱歌">唱歌<input type="checkbox" name="hobbys" value="电影">电影<br><input type="submit">
</form>
</body>
</html>

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Arrays;@WebServlet( "/RequestTest")
public class RequestTest extends HttpServlet {protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {}protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String username=request.getParameter("username");String password=request.getParameter("password");String[] hobbys=request.getParameterValues("hobbys");System.out.println("======================");System.out.println(username+"\n"+password);//response.sendRedirect("CheckCode");System.out.println(Arrays.toString(hobbys));System.out.println("======================");//通过请求转发,这里的斜杠代表web应用request.getRequestDispatcher("/CheckCode").forward(request,response);}
}

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;@WebServlet( "/CheckCode")
public class CheckCode extends HttpServlet {protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {}protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//让浏览器每隔一段时间自动刷新response.setHeader("refresh","3");//在内存中创建一个图片BufferedImage image = new BufferedImage(80, 20, BufferedImage.TYPE_INT_RGB);//得到笔Graphics2D graphics = (Graphics2D)image.getGraphics();//设置图片的背景颜色graphics.setColor(Color.white);//填充图形graphics.fillRect(0,0,80,20);//给图片写数据graphics.setColor(Color.BLACK);graphics.setFont(new Font(null,Font.BOLD,20));graphics.drawString(makeNum(),0,20);//告诉浏览器这个请求用图片的格式打开response.setContentType("image/jpeg");//不让浏览器缓存response.setDateHeader("expires",-1);response.setHeader("Cache-Control","no-Cache");response.setHeader("pragma","no-Cache");//把图片写给浏览器ImageIO.write(image,"jpeg",response.getOutputStream());}private String makeNum(){Random random = new Random();String s = random.nextInt(99999999) + "";StringBuffer buffer = new StringBuffer();for(int i=0;i<8-s.length();i++)buffer.append("0");s=buffer.toString()+s;return s;}
}