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利用servlet转发技术实现统计form表单中字母次数

2016-09-12 15:21 323 查看

需求是利用servlet转发技术，实现对html网页中用户输入的内容进行统计，统计每个字母出现的次数，忽略大小写。其中统计功能在一个servlet中，转发功能在另一个servlet中。

1.新建dynamic web project，命名为CounterCharacter

2.在webContent目录中新建index.html文件，设置form表单

[html] view
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<!DOCTYPE html>

<html>

<head>

<meta charset="UTF-8">

<title>Insert title here</title>

</head>

<body>

<form action="/CountCharacter/LetterCountServlet" method="post">

请输入文章<textarea rows="5" cols="50" name="content"></textarea>

<input type="submit" value="提交"/>

</form>

</body>

</html>

3.在JavaResource/src目录下新建一个包，命名为servletDemo，在该包中新建一个servlet，命名为LetterCountServlet,主要负责统计用户输入的内容中每个字母出现的次数

[java] view
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package servletDemo;



import java.io.IOException;



import javax.servlet.RequestDispatcher;

import javax.servlet.ServletContext;

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 LetterCountServlet

* 统计用户输入内容中每个字母出现次数

*/

@WebServlet(asyncSupported = true, urlPatterns = { "/LetterCountServlet" })

public class LetterCountServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;



    /**

     * @see HttpServlet#HttpServlet()

     */

    public LetterCountServlet() {

        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

        System.out.println("Servlet works");



        //获得form表单提交的内容

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



        //忽略大小写，把用户输入全部转换成大写

        content = content.toUpperCase();



        int[] times = new int[26];



        for(int i = 0; i < content.length();i++)

        {

            char c = content.charAt(i);

            //判断C是不是字母

            if(Character.isLetter(c))

                times[c-'A']++;

        }



        //交给下一个servlet显示结果

        ServletContext context = getServletContext();

        //添加count属性

        context.setAttribute("count", times);



        //跳转至下一个servlet

        RequestDispatcher dispatcher = context.getRequestDispatcher("/ResulstServlet");



        dispatcher.forward(request, response);

    }



    /**

     * @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);

    }



}

4.在servletDemo包中新建一个servlet，命名为ResultServlet，主要负责统计结果的输出

[html] view
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package servletDemo;



import java.io.IOException;

import java.io.PrintWriter;



import javax.servlet.ServletContext;

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 ResulstServlet

* 显示统计结果

*/

@WebServlet(asyncSupported = true, urlPatterns = { "/ResulstServlet" })

public class ResulstServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;



    /**

     * @see HttpServlet#HttpServlet()

     */

    public ResulstServlet() {

        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

        ServletContext context = getServletContext();

        int[] times = (int[]) context.getAttribute("count");



        //输出结果

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

        PrintWriter out = response.getWriter();



        for(int i = 0; i < times.length;i++)

        {

            char c = (char) ('A'+ i);

            int frequency = times[i];



            out.println("字母："+c+"，出现次数"+frequency+"次！<br/>");

        }

    }



    /**

     * @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);

    }



}

5.OK,功能实现

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标签： servlet

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