求助,不知道是哪里错误了
牙签爱狐狸 2018-02-08 10:59:31 News.Dao.java
package com.newsmanager.dao;
import java.sql.Connection;
import java.sql.Date;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import com.newsmanager.entity.News;
/**
* @author heqiheqi
*方法:查询所有新闻集合
*@return 返回所有新闻集合
*date 2018/2/6
*/
public class NewsDao{
public List<News> getNewsList(Integer pageNumber,Integer pageSize){
List<News> newsList=new ArrayList<News>();
Connection connection=null;
ResultSet resultSet=null;
Statement statement=null;
try {
//1.加载驱动
Class.forName("com.mysql.jdbc.Driver");
//2.驱动管理器获取数据库连接
String url="jdbc:mysql://127.0.0.1:3306/test";
String username="root";
String passwrod="root";
connection=DriverManager.getConnection(url,username,passwrod);
//3.获取statement,执行sql语句
statement=connection.createStatement();
//定义开始的条数为页码数-1再乘以页面显示的条数
int startSize= (pageNumber-1)*pageSize;
//执行查询并把结果返回到resultset值里去
resultSet=statement.executeQuery("select * from news limit"+startSize+","+pageSize);
//执行sql返回结果并解析
while (resultSet.next()) {
int newsId=resultSet.getInt("newsid");
String newsContent=resultSet.getString("newscontent");
String newsTitle=resultSet.getString("newstitle");
String newsStatus=resultSet.getString("newsstatus");
String newsType=resultSet.getString("newstype");
Date createTime=resultSet.getDate("createtime");
News news=new News(newsTitle, newsContent, newsStatus, newsType, createTime, newsId);
newsList.add(news);
}
} catch (Exception e) {
// TODO: handle exception
}finally {
try {
if (statement!=null) {
statement.close();
}
if (resultSet!=null) {
resultSet.close();
}
if (connection!=null) {
connection.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return newsList;
}
/**
* @author heqiheqi
*方法:查询新闻总条数
*@return 返回总条数
*date 2018/2/7
*/
public int getCount(){
int count=0;
Connection connection=null;
ResultSet resultSet=null;
Statement statement=null;
try {
//1.加载驱动
Class.forName("com.mysql.jdbc.Driver");
//2.驱动管理器获取数据库连接
String url="jdbc:mysql://127.0.0.1:3306/test";
String username="root";
String passwrod="root";
connection=DriverManager.getConnection(url,username,passwrod);
//3.获取statement,执行sql语句
statement=connection.createStatement();
resultSet=statement.executeQuery("selcet count(*) from news");
if(resultSet.next()){
count=resultSet.getInt(1);
}
} catch (Exception e) {
// TODO: handle exception
}finally{
try {
if (statement!=null) {
statement.close();
}
if (resultSet!=null) {
resultSet.close();
}
if (connection!=null) {
connection.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return count;
}
}
NewsServlet.java
package com.newsmanager.servlet;
import java.io.IOException;
import java.util.List;
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 com.newsmanager.dao.NewsDao;
import com.newsmanager.entity.News;
/**
* Servlet implementation class NewsServlet
*/
@WebServlet(description = "我爱贺琪", urlPatterns = { "/NewsServlet" })
public class NewsServlet extends HttpServlet {
private NewsDao newsDao;
@Override
public void init() throws ServletException {
newsDao=new NewsDao();
}
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public NewsServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
public void doPost(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
//定义初始页面为1
Integer pageNumber=1;
String pn=request.getParameter("pageNumber");
if(pn!=null){
pageNumber=Integer.valueOf(pn);
}
if(pageNumber<=1){
pageNumber=1;
}
int count=newsDao.getCount();
//每页显示10调数据
Integer pageSize=10;
int pageCount;
if(count%pageSize==0){
pageCount=count/pageSize;
}else{
pageCount=count/pageSize+1;
}
if(pageNumber>pageCount){
pageNumber=pageCount;
}
//调用查询集合的方法
List<News> newsList=newsDao.getNewsList(pageNumber,pageSize);
//添加到reques作用域中
request.setAttribute("newsList", newsList);
request.setAttribute("pageNumber", pageNumber);
request.setAttribute("pageCount", pageCount);
//转发到newslist界面
request.getRequestDispatcher("newsList.jsp").forward(request, response);
}
}
newsList.java
package com.newsmanager.servlet;
import java.io.IOException;
import java.util.List;
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 com.newsmanager.dao.NewsDao;
import com.newsmanager.entity.News;
/**
* Servlet implementation class NewsServlet
*/
@WebServlet(description = "我爱贺琪", urlPatterns = { "/NewsServlet" })
public class NewsServlet extends HttpServlet {
private NewsDao newsDao;
@Override
public void init() throws ServletException {
newsDao=new NewsDao();
}
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public NewsServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
public void doPost(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
//定义初始页面为1
Integer pageNumber=1;
String pn=request.getParameter("pageNumber");
if(pn!=null){
pageNumber=Integer.valueOf(pn);
}
if(pageNumber<=1){
pageNumber=1;
}
int count=newsDao.getCount();
//每页显示10调数据
Integer pageSize=10;
int pageCount;
if(count%pageSize==0){
pageCount=count/pageSize;
}else{
pageCount=count/pageSize+1;
}
if(pageNumber>pageCount){
pageNumber=pageCount;
}
//调用查询集合的方法
List<News> newsList=newsDao.getNewsList(pageNumber,pageSize);
//添加到reques作用域中
request.setAttribute("newsList", newsList);
request.setAttribute("pageNumber", pageNumber);
request.setAttribute("pageCount", pageCount);
//转发到newslist界面
request.getRequestDispatcher("newsList.jsp").forward(request, response);
}
}
这是代码,不知道哪错了,求大佬们帮帮忙!
ide:ecplise
服务器:tomcat 7.0
jdk1.7