实验三 Servlet 相关技术

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我是靠谱客的博主怕孤独蜻蜓，最近开发中收集的这篇文章主要介绍实验三 Servlet 相关技术，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

一、实验目的：

理解 Servlet 的工作原理，掌握 Servlet 的应用开发方法；掌握常见 Servlet ；

二、实验环境：

1.理解 Servlet 的应用。

2.掌握 Servlet 的编程技术。

3.熟练使用 Eclipse 开发 Servlet 应用

三、实验内容：

（一）用 Servlet 获取表单数据

1. 建立一个 Servlet 文件 accept.java 和一个 register.jsp 文件，实现用 Servlet 实现获取表单数据的功能。

Accept.java

package com.yiibai;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletConfig;

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.*;

import javax.servlet.*;

import javax.servlet.http.*;

/**

 * Servlet implementation class accept

 */

@WebServlet("/accept")

public class accept extends HttpServlet {

public String codeToString(String str)

{//处理中文字符串的函数

String s=str;

try

{

byte tempB[]=s.getBytes("ISO-8859-1");

s=new String(tempB);

return s;

}

catch(Exception e)

{

return s;

}

}

public void init(ServletConfig config) throws ServletException

{

super.init(config);

}

public void doPost(HttpServletRequest request,HttpServletResponse response)

throws ServletException,IOException

{

//设置mime

response.setContentType("text/html;charset=utf-8");

PrintWriter out=response.getWriter();

out.println("<HTML><head><title>接收新用户注册</title></head><BODY>");

out.println("这是新用户注册所提交的数据：<br>");

out.println("用户名是："+codeToString(request.getParameter("username"))+"<br>");

out.println("密码是："+codeToString(request.getParameter("userpassword"))+"<br>");

out.println("性别是："+codeToString(request.getParameter("sex"))+"<br>");

out.println("出生年月是："+request.getParameter("year")+request.getParameter("month")+request.getParameter("day")+"<br>");

out.println("电子邮箱是："+request.getParameter("email")+"<br>");

out.println("家庭住址是："+codeToString(request.getParameter("address"))+"<br>");

out.println("</body> </html>");

}

       

    /**

     * @see HttpServlet#HttpServlet()

     */

    public accept() {

        super();

        // TODO Auto-generated constructor stub

    }



/**

 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)

 */

protected void doGet1(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

response.getWriter().append("Served at: ").append(request.getContextPath());

}



/**

 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)

 */

protected void doPost1(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

doGet(request, response);

}



}

<%@ page contentType="text/html;charset=utf-8"%>

<script language="javascript"> function on_submit()

{//验证数据的合法性

if (form1.username.value == "")

{

alert("用户名不能为空，请输入用户名！");

form1.username.focus(); return false;

} if (form1.userpassword.value == "")

{

alert("用户密码不能为空，请输入密码！");

form1.userpassword.focus(); return false;

} if (form1.reuserpassword.value == "")

{

alert("用户确认密码不能为空，请输入密码！");

form1.reuserpassword.focus(); return false;

} if (form1.userpassword.value != form1.reuserpassword.value)

{

alert("密码与确认密码不同");

form1.userpassword.focus();

return false;

} if (form1.email.value.length!= 0)

{ for (i=0; i<form1.email.value.length; i++)

if (form1.email.value.charAt(i)=="@") break;

if (i==form1.email.value.length)

{ alert("非法EMail地址！"); form1.email.focus(); return false;

}

} else

{

alert("请输入Email！"); form1.email.focus(); return false;

}

}

</script>

<html>

<head>

<title>新用户注册</title>

</head>

<body>

<form method="POST" action="accept" name="form1" onsubmit="return on_submit()">

新用户注册<br>

用户名(*)：<input type="text" name="username" size="20"><br>

 密  码(*)：<input type="password" name="userpassword" size="20"><br>

 再输一次密码(*)：<input type="password"name="reuserpassword"size="20"><br>

 性别：<input type="radio" value="男"checked name="sex">男<input type="radio" name="sex" value="女">女<br>

  出生年月：<input name="year" size="4" maxlength=4>年 <select name="month">

<option value="1" selected>1</option>

<option value="2">2</option>

<option value="3">3</option>

<option value="4">4</option>

<option value="5">5</option>

<option value="6">6</option>

<option value="7">7</option>

<option value="8">8</option>

<option value="9">9</option>

<option value="10">10</option>

<option value="11">11</option>

<option value="12">12</option>

</select>月<input name="day" size="3" maxlength=4>日<br>

 电子邮箱(*)：<input name="email" maxlength=28><br>

 家庭住址：<input type="text" name="address" size="20"><br>

<input type="submit" value="提交" name="B1"><input type="reset" value="全部重写" name="B2"><br>

</form>

</body>

</html>

过滤器

【步骤 1】编写一个过滤器改变请求编码:

loginform.html

<html>

<head>

<title>使用过滤器改变请求编码</title>

<meta http-equiv="Content-Type" content="text/html;charset=GB2312">

</head>

<body>

<center>

<h2>请输入用户名和口令：</h2>

<form method="post" action="CheckParamServlet">

<table>

<tr>

<td>用户名：</td>

<td><input name="name" type="text"></td>

</tr>

<tr>

<td>口 令：</td>

<td><input name="pass" type="password"></td>

</tr>

<tr>

<td></td>

<td>

<input name="ok" type="submit" value="提交">

<input name="cancel" type="reset" value="重置">

</td>

</tr>

</table>

</form>

</center>

 

</body>

</html>

【步骤 2】编写处理请求参数的 Servlet，代码如

package com.yiibai;

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 CheckParamServlet

 */

@WebServlet("/CheckParamServlet")

public class CheckParamServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

       

    /**

     * @see HttpServlet#HttpServlet()

     */

    public CheckParamServlet() {

        super();

        // TODO Auto-generated constructor stub

    }



/**

 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)

 */

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

//response.getWriter().append("Served at: ").append(request.getContextPath());

String name = request.getParameter("name");

String pass = request.getParameter("pass");

response.setContentType("text/html;charset=gb2312");

PrintWriter out = response.getWriter();

out.println("<html><head><title>Param Test</title></head>");

out.println("<h3 align=center>你的用户名为："+name+"</h3>");

out.println("<h3 align=center>你的口令为："+pass+"</h3>");

out.println("</body></html>");

}



/**

 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)

 */

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

doGet(request, response);

}

}

【步骤 3】修改 web.xml 文件，加入下面代码：

<servlet>

<servlet-name>CheckParamServlet</servlet-name>

<servlet-class>CheckParamServlet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>CheckParamServlet</servlet-name>

<url-pattern>/CheckParamServlet</url-pattern>

</servlet-mapping>

【步骤 5】过滤器代码如下：

package filter;

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.annotation.WebFilter;

@WebFilter("/*")

public class EncodingFilter implements Filter {

protected String encoding = null;

protected FilterConfig config;

    public EncodingFilter() {

        // TODO Auto-generated constructor stub

    }

public void destroy() {

// TODO Auto-generated method stub

}

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

if (request.getCharacterEncoding() == null) {

// 得到指定的编码

String encode = getEncoding();

if (encode != null) {

//设置 request 的编码

request.setCharacterEncoding(encode);

response.setCharacterEncoding(encode);

}

}

chain.doFilter(request, response);

}

protected String getEncoding() {

return encoding;

}

public void init(FilterConfig fConfig) throws ServletException {

// TODO Auto-generated method stub

this.config = fConfig;

// 得到在 web.xml 中配置的编码

this.encoding = fConfig.getInitParameter("Encoding");

}

}

【步骤 6】在 web.xml 文件中配置过滤器，加入下面代码：

<filter>

<filter-name>EncodingFilter</filter-name>

<filter-class>filter.EncodingFilter</filter-class>

<init-param>

<param-name>Encoding</param-name>

<param-value>gb2312</param-value>

</init-param>

  </filter>

  <filter-mapping>

<filter-name>EncodingFilter</filter-name>

<url-pattern>/*</url-pattern>

  </filter-mapping>

1.试简述过滤器有哪些功能？

过滤器对客户和资源之间的请求和响应进行过滤。请求经过一个过滤器到达servlet，servlet产生响应再经过过滤器到达客户，这就在请求和响应到达目的地之前对它们进行监视。过滤器的存在对servlet和客户都是透明的。

2. 如何理解过滤器链。

客户与资源之间建立多个过滤器，从而形成过滤器链。在过滤器链中每个过滤器都是请求处理，然后将请求交给链中的下一个过滤器（如果它是链中的最后一个，将交给实际的资源。）类似的，在响应到达客户之前，每个过滤器以相反的顺序对响应处理。

四、附加练习实现一个查询天气的 web 程序；

使用表单完成城市的输入，提交使用 ajax 完成查询显示；

Weather forecast.html

<!DOCTYPE html>

<html>

<head>

<meta charset="GB2312">

<title></title>

</head>

<body>

 <input type="text" name="" id="numb" value="" />

 <button type="button"onclick="loadXMLDoc()">获取天气</button>

 <p id="text"></p>



</body>

<script type="text/javascript">

function loadXMLDoc(){

document.getElementById("text").innerHTML="请填写城市";

var x,url;

//获取id="numb"的值

x=document.getElementById("numb").value;

console.log(x);

 //得到对象

  var xhr=new XMLHttpRequest();

url="http://api.seniverse.com/v3/weather/now.json?key=WNEUXAAE2G&language=zh-Hans&unit=c&location="+encodeURI(x)

console.log(url);

//打开请求

  xhr.open("get",url,false);//同步

  //发送请求

  xhr.send(null);  

  //判断响应状态

  if(xhr.status==200){

//获取响应结果

obj=JSON.parse(xhr.responseText);

document.getElementById("text").innerHTML=obj.results[0].location.name+" "+obj.results[0].now.text+" "+obj.results[0].now.temperature;

// document.getElementById("text").innerHTML=xhr.responseText;

  // console.log(xhr.responseText);

  }else{

  console.log("状态码："+xhr.status+",原因："+xhr.responseText)

  }

}

</script>

</html>