纯Servlet简单分页代码

运行方式：

1）直接复制代码，可以直接拉到底下复制

2）启动Tomcat

3）跳转请求/top10

 

分页功能主要注意点：

1）London：只有一个？表示在当前页传值，主要是为了完成分页功能

2）Select City：当前页不传值跳转的超链接格式

3）List如何赋值给另一个List

List londonAttractions= new ArrayList(3){{
    add("b1");
    add("b2");
    add("b3");
}};
List attractions = null;
attractions = londonAttractions;

注意点1、2相关内容，点击跳转

注意点3相关内容，点击跳转

 

分页主要代码：

判断当前第几页Page

int page = 1;
String pageParameter = req.getParameter("page");
if (pageParameter != null){
   try{
      page = Integer.parseInt(pageParameter);
   }catch (NumberFormatException e){
      e.printStackTrace();
   }
   if (page > 2){
       page = 1;
   }
}

根据page的值来决定显示哪一页消息

int start = page * 5 - 5;
for (int i = start; i < start + 5; i++) {
     writer.println(attractions.get(i) + "
");
}

 

完整Servlet代码：

package com.fxy.servlet;

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.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

@WebServlet(name = "Top10Servlet",urlPatterns = {"/top10"})
public class Top10Servlet extends HttpServlet{
    private static final long serialVersionUID = 987654321L;

    private List londonAttractions;
    private List parisAttractions;
    public void init() throws ServletException{
        londonAttractions = new ArrayList(10);
        londonAttractions.add("a1");
        londonAttractions.add("a2");
        londonAttractions.add("a3");
        londonAttractions.add("a4");
        londonAttractions.add("a5");
        londonAttractions.add("a6");
        londonAttractions.add("a7");
        londonAttractions.add("a8");
        londonAttractions.add("a9");
        londonAttractions.add("a10");

        parisAttractions = new ArrayList(10){{
            add("b1");
            add("b2");
            add("b3");
            add("b4");
            add("b5");
            add("b6");
            add("b7");
            add("b8");
            add("b9");
            add("b10");
        }};

    }

    /**
     * urlPatterns = {"/top10"}拦截请求第一次进入这个servlet调用的方法
     * 快捷键：Ctrl+O 重写方法
     */
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String city = req.getParameter("city");
        if (city != null && ( city.equals("london") || city.equals("paris") )) {
            showAttractions(req,resp,city);
        }else {
            showMainPage(req,resp);
        }
    }

    /**
     * 首页，注意超链接格式
     * London
     * 只有一个？表示在当前页传值，主要是为了完成分页功能
     */
    private void showMainPage(HttpServletRequest req, HttpServletResponse resp) throws IOException {
        resp.setContentType("text/html");
        PrintWriter writer = resp.getWriter();
        writer.print(""+""+
            ""+
            "Please select a city:"+
            "
London"+
            "Paris
"
        );
    }

    /**
     * 显示数据页面，注意：
     * 1）List如何赋值给另一个List
     * 2）当前页不传值跳转的超链接格式Select City
     */
    private void showAttractions(HttpServletRequest req, HttpServletResponse resp, String city) throws IOException {
        int page = 1;
        String pageParameter = req.getParameter("page");
        if (pageParameter != null){
            try{
                page = Integer.parseInt(pageParameter);
            }catch (NumberFormatException e){
                e.printStackTrace();
            }
            if (page > 2){
                page = 1;
            }
        }

        List attractions = null;
        if (city.equals("london")){
            attractions = londonAttractions;
        }else if (city.equals("paris")){
            attractions = parisAttractions;
        }
        resp.setContentType("text/html");

        PrintWriter writer = resp.getWriter();
        writer.println(""+
            ""+
            "");
        writer.println("Select City");
        writer.println("
Page"+ page + "
");

        int start = page * 5 - 5;
        for (int i = start; i < start + 5; i++) {
            writer.println(attractions.get(i) + "
");
        }

        writer.print("
"+
            "Page 1"
        );
        writer.print("
"+
                "Page 2"
        );
        writer.println("");

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}