servlet+jsp+java实现Web应用

servlet+jsp+java实现Web应用

环境：

1，eclipse
2，tomcat
3，eclipse tomcat 插件

开发过程：

1，建立一个Dynamic Web Project

2，创建一个欢迎页面

页面可以是jsp/html，我们选择一个jsp页面（放在WebContent内）

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h1>Do you come in?</h1>
<form method="post" action="hello.do">
    Select:<br>
    <select>
        <option>yes
        <option>no
    </select>
    <center>
        <input type="submit">
    </center>
</form>
</body>
</html>

3，向工程添加一个servlet文件

package com.example;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class Welcome
 */
@WebServlet("/Welcome")
public class Welcome extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        String c = request.getParameter("select");
        if(c.equals("yes"))
            out.print("Welcome!");
        else
            out.print("I don't like you!");
         //带参跳到另一个页面
         request.setAttribute("token", token);
         request.getRequestDispatcher("welcome.jsp").forward(request,response);

    }

}

4，创建welcome.jsp页面，并接受参数值

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Insert title here</title>

<%
String token = request.getParameter("token");//用request得到 
%>
<style>  
        #ifr_fr{  
             84%;  
            height: 700px;  
        }  
    </style>  
</head>
<body >
welcome to rzzx1.
<iframe id="ifr_fr" name="ifr_fr" frameborder="0"  src=""></iframe>
</body>
</html>

5，创建一个web.xml

web.xml用来建立servlet与jsp的关系（需要放在WEB-INF内）。

　根据不同的url来调用不同的servlet来进行处理。

<?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
  <display-name></display-name>
  <servlet>
    <servlet-name>Welcome</servlet-name>//要与下面的名称相同
    <servlet-class>com.example.Welcome</servlet-class>//调用的类的位置
   </servlet>
   <servlet-mapping>
    <servlet-name>Welcome</servlet-name>
    <url-pattern>/hello.do</url-pattern>//url标识
  </servlet-mapping>
</web-app>

6，测试地址：http://localhost:8080/webtest/hello.do

7，可能会提示：HTTP method GET is not supported by this URL

解决方案：

public void doPost(HttpServletR……
改成：
public void service(HttpServletR……