• servlet从jsp到jsp实现例子


    已登录页面为例子:

    1.login.jsp

    <%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    <form action="login">
        username:<input  type="text" name="username" /><br>
        password:<input type="password" name="password" ><br>
        repassword:<input type="password" name="repassword"><br>
        age:<input type="text" name="age"/>
        <input type="submit" value="submits">
    </form>
    
    </body>
    </html>

    2.在xml中配置好传输信息

     <?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
     
      <servlet>
          <servlet-name>Login</servlet-name>
          <servlet-class>com.servlet.LoginServlet</servlet-class>
      </servlet>
      
      <servlet-mapping>
          <servlet-name>Login</servlet-name>
          <url-pattern>/login</url-pattern>
      </servlet-mapping>
    
    </web-app>

    3.通过xml配置信息找到对应的处理class类。

    package com.servlet;
    
    import java.io.IOException;
    import java.io.PrintWriter;
    import java.util.ArrayList;
    import java.util.List;
    
    import javax.servlet.RequestDispatcher;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    public class LoginServlet extends HttpServlet
    {
        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp)
                throws ServletException, IOException
        {
           String username = req.getParameter("username");
           String password = req.getParameter("password");
           String repassword = req.getParameter("repassword");
           int age = Integer.parseInt(req.getParameter("age"));
           
           String result = "";
           if(age > 18)
           {
               result = "success";
           }
           else
           {
               result += "age <= 18";
           }
           if(!password.equals(repassword))
           {
               result += "password != repassword";
           }
           
           req.setAttribute("username", username);
           req.setAttribute("age", age);
           //转发
           RequestDispatcher rd = req.getRequestDispatcher("result.jsp");
           
           //遍历一个list。额外加上的。测试request后得到的是一个枚举类型数据
           List<String> list = new ArrayList<String>();
           for(int i = 0; i < 100; i++)
           {
               list.add(String.valueOf(i));
           }
           req.setAttribute("list", list);
           
           
        }
    }

    4.结果页面

    <%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <%@ page import="java.util.List" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    
    username:<%= request.getAttribute("username") %>
    
    age:<%= request.getAttribute("age") %>
    
    <%
        List<String> list = (List<String>)request.getAttribute("list");
        for(int i = 0; i < list.size(); i++)
        {
            %>
            <%= list.get(i) %><br>
            <%
        }
    
    %>
    </body>
    </html>

    完成,收工,其中有些变量没有得到值,是因为没有将其存入到request容器中。

    只是个例子,如果需要,留下言,我可以将其他的补全。

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  • 原文地址:https://www.cnblogs.com/feiguo/p/3747493.html
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