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  • 网页计数器例子

    package com.bjsxt.servlet;

    import java.io.BufferedReader;
    import java.io.BufferedWriter;
    import java.io.FileReader;
    import java.io.FileWriter;
    import java.io.IOException;

    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;

    public class NumServlet extends HttpServlet {

    //覆写init初始化方法,将数据读取到ServletContext对象中
    @Override
    public void init() throws ServletException {
    //获取文件中的计数器数据
    //获取文件路径
    String path=this.getServletContext().getRealPath("/nums/nums.txt");
    //声明流对象
    FileReader fr=null;
    BufferedReader br=null;
    try {
    fr=new FileReader(path);
    br=new BufferedReader(fr);
    String nums=br.readLine();
    System.out.println(nums);
    this.getServletContext().setAttribute("nums", nums);
    } catch (Exception e) {
    e.printStackTrace();
    }finally{
    try {
    fr.close();
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    try {
    br.close();
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    }
    }

    //覆写销毁方法,存储计数器到文件中
    @Override
    public void destroy() {
    //获取网页计数器
    int nums=(int) this.getServletContext().getAttribute("nums");
    //获取文件路径
    String path=this.getServletContext().getRealPath("/nums/nums.txt");
    //声明流对象
    BufferedWriter bw=null;
    FileWriter fw=null;
    try {
    fw=new FileWriter(path);
    bw=new BufferedWriter(fw);
    bw.write(nums+"");
    bw.flush();
    } catch (Exception e) {
    e.printStackTrace();
    }finally{
    try {
    fw.close();
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    try {
    bw.close();
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    }
    }

    }

    2:web.xml配置servlet的load-on-startup

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  • 原文地址:https://www.cnblogs.com/lwh-12345/p/13564668.html
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