新聞發布系統項目

本文轉載自查看原文 2017-04-27 22:36 2454

增刪改查

下面來看看我們真實的需要做的

登錄后跳轉的頁面

添加新聞===文件上傳

編輯新聞----修改刪除

添加主題===分類

編輯主題

web項目里后台的分層

一：先說登錄主要代碼從我的數據庫里拿數據，servlet調用，然后被前台調用。代碼如下：

@Override
    public boolean isLogin(UserInfo info) throws Exception {
        boolean flag=false;
        String sql="select count(*) from login where username=? and userpwd=?";
        ResultSet rs=executeQuery(sql, info.getUserName(),info.getUserPwd());
        if (rs.next()) {
            int count=rs.getInt(1);
            if(count>0){
                flag=true;
            }
        }
        return flag;
    }

我的servlet調用===判斷加效驗===加我的注銷===移除session記錄的賬戶

request.setCharacterEncoding("utf-8");
        if (request.getParameter("uname")!=null) {
            String uname=request.getParameter("uname");
            String upwd=request.getParameter("upwd");
            
            //拼接成一個用戶對象
            UserInfo info=new UserInfo();
            info.setUserName(uname);
            info.setUserPwd(upwd);
            
            IUserInfoService service=new UserInfoService();
            try {
                boolean flag = service.isLogin(info);
             if (flag) {  //登錄成功
                    //3.記錄session
                    request.getSession().setAttribute("uname", uname);
                    request.setAttribute("loginsuccess","true");
                    //4.轉發或者重定向   轉發不需要加項目名稱
                    request.getRequestDispatcher("/NewsServlet").forward(request, response);
                    return;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            
        }
    if ("".equals(request.getParameter("uname")) || "".equals(request.getParameter("upwd"))) {
            request.setAttribute("longinfailure","true");
            request.getRequestDispatcher("/NewsServlet").forward(request, response);
            return;
        }
 
        request.setCharacterEncoding("utf-8");

        if(request.getSession().getAttribute("uname")!=null){
            request.setCharacterEncoding("utf-8");
        
            request.getSession().removeAttribute("uname");
            //重定向
            response.sendRedirect("/News/NewsServlet");
            return;
        }

我的頁面調用：

<script type="text/javascript">
    
<%if("true".equals(request.getAttribute("longinfailure"))){%>
    alert("用戶名或密碼為空！");
<%}%>
    
</script>

</head>

<body>
    <div id="header">
        <div id="top_login">
            <form action="<%=path%>/UserInfoNewServlet" method="post">
                <label> 登錄名 </label> <input type="text" id="uname" name="uname"
                    value="" class="login_input" /> <label> 密&#160;&#160;碼 </label> <input
                    type="password" id="upwd" name="upwd" value="" class="login_input" />
                <input type="submit" class="login_sub" value="登錄" />

二：下面說說我的分頁
定義了一個util實體包供我分頁使用

package cn.news.util;

import java.util.List;

import cn.news.entity.NewsInfo;

public class Page {
    // 當前頁
    private int pageIndex;
    // 頁面總記錄數
    private int pageSize;
    // 本業顯示真實數據
    private List<NewsInfo> list;
    // 總頁數
    private int totalPages;
    // 總記錄數
    private int totalRecords;

    public int getPageIndex() {
        return pageIndex;
    }

    public void setPageIndex(int pageIndex) {
        this.pageIndex = pageIndex;
    }

    public int getPageSize() {
        return pageSize;
    }

    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }

    public List<NewsInfo> getList() {
        return list;
    }

    public void setList(List<NewsInfo> list) {
        this.list = list;
    }

    public int getTotalPages() {
        return totalPages;
    }

    public void setTotalPages(int totalPages) {
        this.totalPages = totalPages;
    }

    public int getTotalRecords() {
        return totalRecords;
    }

    public void setTotalRecords(int totalRecords) {
        this.totalRecords = totalRecords;
    }

}

主要從數據庫里拿到的分頁代碼如下：

@Override
    public List<NewsInfo> getPageInfos(int pageIndex, int pageSize) throws Exception {
        List<NewsInfo> list=new ArrayList<NewsInfo>();

        String sql="SELECT * FROM newinfo LIMIT ?,?";
        rs=executeQuery(sql,(pageIndex-1)*pageSize,pageSize);
        if (rs!=null) {
            while (rs.next()) {
                NewsInfo info=new NewsInfo();
                int nid=rs.getInt("nid");
                String ntitle=rs.getString("ntitle");
                String nauthor=rs.getString("nauthor");
                Date npublisherdate=rs.getDate("npublisherdate");
                String ncontent=rs.getString("ncontent");
                int tid=rs.getInt("tid");
                
                info.setNauthor(nauthor);
                info.setNcontent(ncontent);
                info.setNid(nid);
                info.setNpublisherdate(npublisherdate);
                info.setNtitle(ntitle);
                info.setTid(tid);
                
                list.add(info);
            }
        }
        return list;
    }

@Override
    public int selectnewsall() throws Exception {
        String sql="SELECT count(1) FROM newinfo";
        int count = 0;
        ResultSet rs = executeQuery(sql);
        if (rs.next()) {
            count = rs.getInt(1);
        }
        
        return count;
    }

servlet調用：

    public void pagenews(HttpServletRequest request,HttpServletResponse response) {
        IUserInfoService daoInfoService = new UserInfoService();
        try {
            Page oaPage = new Page();
            // 默認三條數據
            int pageSize = 3;
            oaPage.setPageSize(pageSize);
            // pageIndex(當前頁)
            int myindex = 1;
            
            String pageIndex = request.getParameter("pageIndex");
            if (null!=pageIndex && (!pageIndex.equals(""))) {
                myindex = Integer.parseInt(pageIndex);
            }
            
            // 總頁數賦值=總記錄數/pageSize
            int mytotalPages = 0;
            int ipages = daoInfoService.selectnewsall();
            if (ipages % pageSize == 0) {
                mytotalPages = ipages / pageSize;
            } else {
                mytotalPages = ipages / pageSize + 1;
            }
            oaPage.setTotalPages(mytotalPages);
            if(myindex>oaPage.getTotalPages()){
                myindex=oaPage.getTotalPages();    
                System.out.println(myindex+"1");
            }
            System.out.println("=================================");
            if (myindex<1) {
                myindex=1;
                System.out.println(myindex+"2");
            }
            oaPage.setPageIndex(myindex);
            // 泛型數據賦值
            List<NewsInfo> list = daoInfoService.getPageInfos(oaPage.getPageIndex(), pageSize);
            oaPage.setList(list);

            // 將泛型集合，放入request作用域
            request.setAttribute("list", oaPage);
            // 轉發index.jsp 轉發不用加名稱
            

        } catch (Exception e) {

            e.printStackTrace();
        }
    }
    public void pageNews(HttpServletRequest request,HttpServletResponse response) {
        IUserInfoService daoInfoService = new UserInfoService();
        try {
            Page oaPage = new Page();
            // 默認三條數據
            int pageSize = 3;
            oaPage.setPageSize(pageSize);
            // pageIndex(當前頁)
            int myindex = 1;
            
            String pageIndex = request.getParameter("pageIndex");
            if (null!=pageIndex && (!pageIndex.equals(""))) {
                myindex = Integer.parseInt(pageIndex);
            }
            
            // 給當前頁賦值
            
            // 總頁數賦值=總記錄數/pageSize
            int mytotalPages = 0;
            int ipages = daoInfoService.selectnewsall();
            if (ipages % pageSize == 0) {
                mytotalPages = ipages / pageSize;
            } else {
                mytotalPages = ipages / pageSize + 1;
            }
            oaPage.setTotalPages(mytotalPages);
            if(myindex>oaPage.getTotalPages()){
                myindex=oaPage.getTotalPages();    
                System.out.println(myindex+"1");
            }
        
            if (myindex<1) {
                myindex=1;
                System.out.println(myindex+"2");
            }
            oaPage.setPageIndex(myindex);
            // 泛型數據賦值
            List<NewsInfo> list = daoInfoService.getPageInfos(oaPage.getPageIndex(), pageSize);
            oaPage.setList(list);

            // 將泛型集合，放入request作用域
            request.setAttribute("list", oaPage);
            // 轉發index.jsp 轉發不用加名稱
            
            } catch (Exception e) {
            e.printStackTrace();
            }
    }

dopost

if(request.getParameter("pageIndex")!=null){
            pageNews(request, response);
            request.getRequestDispatcher("/newspages/admin.jsp").forward(request,response);
            return;
        }

pagenews(request, response);
        request.getRequestDispatcher("/index.jsp").forward(request,response);

頁面調用servlet顯示給顧客

<p align="right">
                        當前頁數:[<%=page2.getPageIndex()%>/<%=page2.getTotalPages()%>]&nbsp;
                        <a
                            href="<%=path%>/NewsServlet?pageIndex=<%=page2.getPageIndex() - 1%>">上一頁</a>
                        <a
                            href="<%=path%>/NewsServlet?pageIndex=<%=page2.getPageIndex() + 1%>">下一頁</a>
                        <a
                            href="<%=path%>/NewsServlet?pageIndex=<%=page2.getTotalPages()%>">末頁</a>
                    </p>

登陸后顯示的頁數

<p align="right"> 當前頁數:[${list.pageIndex}/${list.totalPages}]&nbsp;
          <a href="${pageContext.request.contextPath}/NewsServlet?pageIndex=${list.pageIndex-1}">上一頁</a>&nbsp; 
           <a href="${pageContext.request.contextPath}/NewsServlet?pageIndex=${list.pageIndex+1}">下一頁</a>&nbsp; 
           <a href="${pageContext.request.contextPath}/NewsServlet?pageIndex=${list.totalPages}">末頁</a> </p>

三：頁面顯示數據庫里的數據====查找
主要查找Dao層的代碼：

@Override
    public List<NewsInfo> findAll() throws Exception {
        List<NewsInfo> list=new ArrayList<NewsInfo>();

        String sql="select * from newinfo";
        rs=executeQuery(sql);
        if (rs!=null) {
            while (rs.next()) {
                NewsInfo info=new NewsInfo();
                int nid=rs.getInt("nid");
                String ntitle=rs.getString("ntitle");
                String nauthor=rs.getString("nauthor");
                Date npublisherdate=rs.getDate("npublisherdate");
                String ncontent=rs.getString("ncontent");
                int tid=rs.getInt("tid");
                
                info.setNauthor(nauthor);
                info.setNcontent(ncontent);
                info.setNid(nid);
                info.setNpublisherdate(npublisherdate);
                info.setNtitle(ntitle);
                info.setTid(tid);
                
                list.add(info);
            }
        }
        return list;
    }

將數據用循環顯示到頁面在我的主頁面寫：

<ul class="classlist">
                    <%
                        Page page2 = (Page) request.getAttribute("list");
                        for (NewsInfo item : page2.getList()) {
                    %>
                    <li><a href="<%=path%>/news_read.jsp"><%=item.getNtitle()%>
                    </a><span><%=item.getNpublisherdate()%></span></li>
                    <%
                        }
                    %>

四：刪除數據主要數據：

@Override
    public boolean deleteNews(int id) throws Exception {
        String sql="delete from newinfo where nid=?";
        boolean flag=false;
        int count = exeuteUpdate(sql,id);
        if (count>0) {
            flag=true;
        }
        return flag;
    }

el表達式：

<c:if test="${desuccess!=null}">
<script type="text/javascript">
alert("刪除成功！！！");
</script>
</c:if>
</head>
<body>
    <div id="main">
       <div>
        <iframe src="<%=path %>/newspages/console_element/top.jsp" scrolling="no" frameborder="0" width="947px" height="180px"></iframe>
      </div> 
      <div id="opt_list">
         <iframe src="<%=path%>/newspages/console_element/left.jsp" scrolling="no" frameborder="0" width="130px"></iframe>
      </div>
      <div id="opt_area"> 
        <ul class="classlist">
     <c:forEach var="item" items="${list.list}">
         <li> ${item.ntitle}<span> 作者：${item.nauthor}                                          
            &#160;&#160;&#160;&#160; <a href='<%=path%>/NewsServlet?upid=${item.nid}'>修改</a> &#160;&#160;&#160;&#160; 
            <a href='${pageContext.request.contextPath}/NewsServlet?deid=${item.nid}'>刪除</a> 
            </span> 
            </li>
     </c:forEach>

<li><a href="${pageContext.request.contextPath}/NewsServlet?xin=xin" target="_parent">添加新聞</a></li>
<li><a href="${pageContext.request.contextPath}/NewsServlet?kin=kin" target="_parent">編輯新聞</a></li>
所有的dopost數據：

    if (null!=request.getParameter("upid")) {
            System.out.println("1");
            return;
        }
        if (null!=request.getParameter("deid")) {
            System.out.println("2");
            IUserInfoService service=new UserInfoService();
            String deid=request.getParameter("deid");
            System.out.println(deid);
            Integer id=Integer.parseInt(deid);
            boolean flag=false;
            try {
                flag=service.deleteNews(id);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            request.setAttribute("desuccess", flag);
            pageNews(request, response);
            request.getRequestDispatcher("/newspages/admin.jsp").forward(request, response);        
            return;
        }
        if("true".equals(request.getAttribute("loginsuccess"))){
            System.out.println("3");
            pageNews(request, response);
            request.getRequestDispatcher("/newspages/admin.jsp").forward(request, response);
            return;
        }
        if (request.getParameter("kin")!=null) {//index
            pageNews(request, response);
            request.getRequestDispatcher("/newspages/admin.jsp").forward(request,response);
            return;
        }
        if(request.getParameter("pageIndex")!=null){
            pageNews(request, response);
            request.getRequestDispatcher("/newspages/admin.jsp").forward(request,response);
            return;
        }
        if (request.getParameter("xin")!=null) {
        
                try {
                    addnews(request, response);
                    request.getRequestDispatcher("/newspages/news_add.jsp").forward(request, response);
                    IUserInfoService infoService=new UserInfoService();
                    List<NewsInfo> all = infoService.findAll();
                    if (all!=null) {
                        request.getRequestDispatcher("/newspages/admin.jsp").forward(request, response);
                    }else {
                        request.getRequestDispatcher("/newspages/news_add.jsp").forward(request, response);
                    }
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
        return;
        }
        pagenews(request, response);
        request.getRequestDispatcher("/index.jsp").forward(request,response);

今天小編就到這里了

剩余修改下期詳解

希望給大家的知識

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