JSP MVC模式案例之投票系统
【摘要】
create table voteitems( id number(8) primary key, item varchar2(50) not null, times number(8) default 0); create sequence seq_voteitems; insert into voteitems(id,item) v...
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create table voteitems(
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id number(8) primary key,
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item varchar2(50) not null,
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times number(8) default 0
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);
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create sequence seq_voteitems;
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insert into voteitems(id,item) values (seq_voteitems.nextval,'jsp');
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insert into voteitems(id,item) values (seq_voteitems.nextval,'asp');
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insert into voteitems(id,item) values (seq_voteitems.nextval,'asp.net');
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insert into voteitems(id,item) values (seq_voteitems.nextval,'php');
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commit;
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package com.javaweb.dao.util;
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import java.sql.Connection;
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import java.sql.DriverManager;
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import java.sql.ResultSet;
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import java.sql.SQLException;
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import java.sql.Statement;
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public class BaseDao {
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private static String url = "jdbc:oracle:thin:@localhost:1521:orcl";
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private static String driver = "oracle.jdbc.driver.OracleDriver";
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private static String user="scott";
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private static String pwd = "tiger";
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public static Connection getConnection()
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throws ClassNotFoundException, SQLException{
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Class.forName(driver);
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Connection con = DriverManager.getConnection(url,user,pwd);
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return con;
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}
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public static void closeAll(ResultSet rs,Statement stmt,Connection con)
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throws SQLException{
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if(rs!=null)
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rs.close();
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if(stmt!=null)
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stmt.close();
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if(con!=null)
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con.close();
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}
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}
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package com.javaweb.dao;
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import java.util.List;
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import com.javaweb.entity.VoteItems;
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public interface VoteItemsDao {
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public List<VoteItems> findAll();
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public boolean update(int id);
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}
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package com.javaweb.dao.impl;
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import java.sql.Connection;
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import java.sql.PreparedStatement;
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import java.sql.ResultSet;
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import java.sql.SQLException;
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import java.util.ArrayList;
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import java.util.List;
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import com.javaweb.dao.VoteItemsDao;
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import com.javaweb.dao.util.BaseDao;
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import com.javaweb.entity.VoteItems;
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public class VoteItemsDaoImpl extends BaseDao implements VoteItemsDao {
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public static void main(String[] args) {
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System.out.println(new VoteItemsDaoImpl().findAll().size());
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}
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public List<VoteItems> findAll() {
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Connection con = null;
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PreparedStatement pstmt = null;
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ResultSet rs=null;
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List<VoteItems> items=null;
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String sql="select id,item,times from voteitems";
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try {
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con=getConnection();
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items=new ArrayList<VoteItems>();
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pstmt=con.prepareStatement(sql);
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rs=pstmt.executeQuery();
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while(rs.next()){
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VoteItems item=new VoteItems();
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item.setId(rs.getInt(1));
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item.setItem(rs.getString(2));
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item.setTimes(rs.getInt(3));
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items.add(item);
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}
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} catch (ClassNotFoundException e) {
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e.printStackTrace();
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} catch (SQLException e) {
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e.printStackTrace();
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}finally{
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try {
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closeAll(rs, pstmt, con);
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} catch (SQLException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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}
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}
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return items;
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}
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public boolean update(int id) {
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String sql = "update voteitems set times = times + 1 where id = "+id;
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Connection con = null;
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PreparedStatement pstmt = null;
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int n = -1;
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try {
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con = getConnection();
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pstmt = con.prepareStatement(sql);
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n=pstmt.executeUpdate();
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} catch (ClassNotFoundException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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} catch (SQLException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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}finally{
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try {
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closeAll(null, pstmt, con);
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} catch (SQLException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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}
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}
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return n>0;
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}
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}
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package com.javaweb.servlet;
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import java.io.IOException;
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import javax.servlet.ServletException;
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import javax.servlet.http.HttpServlet;
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import javax.servlet.http.HttpServletRequest;
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import javax.servlet.http.HttpServletResponse;
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import com.javaweb.dao.VoteItemsDao;
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import com.javaweb.dao.impl.VoteItemsDaoImpl;
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public class UpdateVoteServlet extends HttpServlet {
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/**
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* The doGet method of the servlet. <br>
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*
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* This method is called when a form has its tag value method equals to get.
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*
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* @param request the request send by the client to the server
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* @param response the response send by the server to the client
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* @throws ServletException if an error occurred
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* @throws IOException if an error occurred
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*/
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public void doGet(HttpServletRequest request, HttpServletResponse response)
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throws ServletException, IOException {
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doPost(request, response);
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}
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/**
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* The doPost method of the servlet. <br>
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*
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* This method is called when a form has its tag value method equals to post.
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*
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* @param request the request send by the client to the server
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* @param response the response send by the server to the client
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* @throws ServletException if an error occurred
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* @throws IOException if an error occurred
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*/
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public void doPost(HttpServletRequest request, HttpServletResponse response)
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throws ServletException, IOException {
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String[] strItems = request.getParameterValues("items");
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VoteItemsDao dao = new VoteItemsDaoImpl();
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for(String item:strItems){
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dao.update(Integer.parseInt(item));
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System.out.println(item);
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}
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//
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response.sendRedirect("ShowVoteServlet");
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//request.getRequestDispatcher("ShowVoteServlet").forward(request, response);
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}
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}
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package com.javaweb.servlet;
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import java.io.IOException;
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import java.util.List;
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import javax.servlet.ServletException;
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import javax.servlet.http.HttpServlet;
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import javax.servlet.http.HttpServletRequest;
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import javax.servlet.http.HttpServletResponse;
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import com.javaweb.dao.VoteItemsDao;
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import com.javaweb.dao.impl.VoteItemsDaoImpl;
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import com.javaweb.entity.VoteItems;
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public class ShowVoteServlet extends HttpServlet {
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/**
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* The doGet method of the servlet. <br>
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*
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* This method is called when a form has its tag value method equals to get.
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*
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* @param request the request send by the client to the server
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* @param response the response send by the server to the client
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* @throws ServletException if an error occurred
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* @throws IOException if an error occurred
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*/
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public void doGet(HttpServletRequest request, HttpServletResponse response)
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throws ServletException, IOException {
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doPost(request, response);
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}
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/**
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* The doPost method of the servlet. <br>
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*
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* This method is called when a form has its tag value method equals to post.
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*
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* @param request the request send by the client to the server
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* @param response the response send by the server to the client
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* @throws ServletException if an error occurred
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* @throws IOException if an error occurred
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*/
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public void doPost(HttpServletRequest request, HttpServletResponse response)
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throws ServletException, IOException {
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VoteItemsDao dao = new VoteItemsDaoImpl();
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List<VoteItems> voteitems = dao.findAll();
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request.setAttribute("voteitems", voteitems);
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request.getRequestDispatcher("vote_result.jsp").
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forward(request, response);
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}
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}
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<%@ page language="java" contentType="text/html; charset=utf-8"%>
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<%@ page import="java.util.*,com.javaweb.entity.*,com.javaweb.dao.*,com.javaweb.dao.impl.*" %>
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<%
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VoteItemsDao voteDao = new VoteItemsDaoImpl();
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List<VoteItems> votes = voteDao.findAll();
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%>
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<html>
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<head>
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<title>调查问卷</title>
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<style>
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.outside{ /* 外层表格 */
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background:url(bg1.jpg);
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font-size:12px;
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padding:0px;
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}
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.title{ /* 表格标题 */
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color:#FFFFFF;
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font-weight:bold;
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text-align:center;
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padding-top:3px;
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padding-bottom:0px;
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}
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.tdoutside{
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padding:0px 1px 4px 1px;
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}
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.inside{ /* 内层表格 */
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width:269px;
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font-size:12px;
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padding:0px;
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margin:0px;
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}
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.tdinside{
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padding:7px 0px 7px 10px;
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background-color:#FFD455;
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}
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form{
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margin:0px; padding:0px;
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}
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input{
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font-size:12px;
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}
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a{
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color:#000000;
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}
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</style></head>
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<body>
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<table class="outside">
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<tr><td class="title">点调查</td></tr>
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<tr><td class="tdoutside">
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<form method="post" action="UpdateVoteServlet">
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<table class="inside" cellspacing="0">
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<tr>
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<td class="tdinside">
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你对哪种技术最感兴趣<br>
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<%
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for(VoteItems v:votes){
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%>
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<input type="checkbox" name="items" value="<%=v.getId() %>"><%=v.getItem() %><br>
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<%
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}
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%>
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<input type="submit" value="提交">
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<a href="ShowResultServlet">查看结果</a>
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</td>
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</tr>
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</table>
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</form>
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</td></tr>
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</table>
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</body>
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</html>
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<%@ page language="java" import="java.util.*,com.javaweb.entity.*" pageEncoding="utf-8"%>
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<%
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String path = request.getContextPath();
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String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
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List<VoteItems> voteitems =
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(List<VoteItems>)request.getAttribute("voteitems");
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%>
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<base href="<%=basePath%>">
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<title>My JSP 'vote_result.jsp' starting page</title>
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<meta http-equiv="pragma" content="no-cache">
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<meta http-equiv="cache-control" content="no-cache">
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<meta http-equiv="expires" content="0">
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<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
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<meta http-equiv="description" content="This is my page">
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<!--
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<link rel="stylesheet" type="text/css" href="styles.css">
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-->
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</head>
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<body>
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<table>
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<%
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for(VoteItems v:voteitems){
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%>
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<tr>
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<td><%=v.getItem() %></td>
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<td><%=v.getTimes() %></td>
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</tr>
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<%} %>
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</table>
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</body>
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</html>
文章来源: aaaedu.blog.csdn.net，作者：tea_year，版权归原作者所有，如需转载，请联系作者。
原文链接：aaaedu.blog.csdn.net/article/details/53138122
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