DAO类(后续无需改变)
package dao; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.Statement; import java.util.ArrayList; import java.util.List; import bean.Category; import util.DBUtil; public class CategoryDAO { public int getTotal(){ String sql="select count(*) from category"; int total=0; try(Connection c=DBUtil.getConnection(); Statement s=c.createStatement();) { ResultSet rs=s.executeQuery(sql); while(rs.next()){ total=rs.getInt(1); } } catch (Exception e) { // TODO: handle exception } return total; } public List<Category> list(int start,int count){ List<Category> categories=new ArrayList<Category>(); String sql="select * from category order by id limit ?,?"; try (Connection c=DBUtil.getConnection(); PreparedStatement ps=c.prepareStatement(sql);){ ps.setInt(1, start); ps.setInt(2, count); ResultSet rs=ps.executeQuery(); while(rs.next()){ Category category=new Category(); category.setId(rs.getInt(1)); category.setName(rs.getString(2)); categories.add(category); } } catch (Exception e) { // TODO: handle exception } return categories; } }
效果一:列表全显示
Servlet类
import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import bean.Category; import dao.CategoryDAO; public class CategoryListServlet extends HttpServlet{ protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{ List<Category>categories=new CategoryDAO().list(0,Short.MAX_VALUE【可变】); request.setAttribute("categories【可变】", categories); request.getRequestDispatcher("/admin/category/categoryList.jsp【可变】").forward(request, response); } }
JSP代码
<table class="table table-striped table-bordered table-hover table-condensed"> <thead>【下面td内容可变】 <tr class="success"> <td>ID</td> <td>图片</td> <td>分类名称</td> <td>编辑</td> <td>删除</td> </tr> </thead> <tbody> <c:forEach items="${categories【可变,取决前面servlet】}" var="categorie【可变】"> <tr> <td>${categorie.id【可变】}</td> <td><img height="40px" src="img/category/${categorie.id【可变】}.jpg"></td> <td>${categorie.name【可变】}</td> <td><a href="categoryEdit?id=${categorie.id【可变】}"><span class="glyphicon glyphicon-edit"></span></a></td> <td><a href="categoryDelete?id=${categorie.id【可变】}"><span class="glyphicon glyphicon-remove"></span></a></td> </tr> </c:forEach> </tbody> </table>
效果二:只显示前5条数据
Servlet类
public class CategoryListServlet extends HttpServlet{ protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{ int start=0;//【可变】 int count=5;//【可变】 List<Category>categories=new CategoryDAO().list(start,count); request.setAttribute("categories【可变】", categories); request.getRequestDispatcher("/admin/category/categoryList.jsp").forward(request, response); } }
JSP代码
//和上一个效果图的JSP代码一样
效果三:可显示首页和末页
Servlet类
public class CategoryListServlet extends HttpServlet{ protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{ int start=0;//起始页的start值 int count=5;//【可变】 try {//如果请求中不带参数start,必须要进行try块的错误处理 start=Integer.parseInt(request.getParameter("start")); } catch (NumberFormatException e) { // TODO: handle exception } int total=new CategoryDAO().getTotal();//总数 int last=0;//末页的start值 if(0==total%count) last=total - count; else last=total - total % count; List<Category>categories=new CategoryDAO().list(start,count);//【可变】 request.setAttribute("last", last);//把last传递给jsp request.setAttribute("categories【可变】", categories);//把categories传递给jsp request.getRequestDispatcher("/admin/category/categoryList.jsp【可变】").forward(request, response); } }
JSP代码
<table class="table table-striped table-bordered table-hover table-condensed"> <thead>【可变】 <tr class="success"> <td>ID</td> <td>图片</td> <td>分类名称</td> <td>编辑</td> <td>删除</td> </tr> </thead> <tbody> <c:forEach items="${categories【可变】}" var="categorie【可变】"> <tr> <td>${categorie.id【可变】}</td> <td><img height="40px" src="img/category/${categorie.id【可变】}.jpg"></td> <td>${categorie.name【可变】}</td> <td><a href="【可变】categoryEdit?id=${categorie.id【可变】}"><span class="glyphicon glyphicon-edit"></span></a></td> <td><a href="【可变】categoryDelete?id=${categorie.id【可变】}"><span class="glyphicon glyphicon-remove"></span></a></td> </tr> </c:forEach> </tbody> <tfoot> <tr> <td colspan="6" align="center"> <!-- 点击超链接时,相当于提交了一个带有参数start的请求 --> <a href="categoryList【可变】?start=0">[首页]</a> <a href="categoryList【可变】?start=${last}">[末页]</a> </td> </tr> </tfoot> </table>
效果四:可显示首页和末页、下一页和上一页
Servlet类
public class CategoryListServlet extends HttpServlet{ protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{ int start=0;//起始页的start值 int count=5;//【可变】 try {//如果请求中不带参数start,必须要进行try块的错误处理 start=Integer.parseInt(request.getParameter("start")); } catch (NumberFormatException e) { // TODO: handle exception } int total=new CategoryDAO().getTotal();//总数 int last=0;//末页的start值 if(0==total%count) last=total - count; else last=total - total % count; int pre=start-count;//上一页的start值 pre=pre>0?pre:0;//边界处理 int next=start+count;//下一页的start值 next=next<last?next:last;//边界处理 List<Category>categories=new CategoryDAO().list(start,count);//【可变】 request.setAttribute("pre", pre);//把last传递给jsp request.setAttribute("next", next);//把last传递给jsp request.setAttribute("last", last);//把last传递给jsp request.setAttribute("categories【可变】", categories);//把categories传递给jsp request.getRequestDispatcher("/admin/category/categoryList.jsp【可变】").forward(request, response); } }
JSP代码
<table class="table table-striped table-bordered table-hover table-condensed【可变】"> <thead> <tr class="success【可变】"> <td>ID</td> <td>图片</td> <td>分类名称</td> <td>编辑</td> <td>删除</td> </tr> </thead> <tbody> <c:forEach items="${categories【可变】}" var="categorie【可变】"> <tr> <td>${categorie.id【可变】}</td> <td><img height="40px" src=【可变】"img/category/${categorie.id}.jpg"></td> <td>${categorie.name【可变】}</td> <td><a href=【可变】"categoryEdit?id=${categorie.id}"><span class="glyphicon glyphicon-edit"【可变】></span></a></td> <td><a href=【可变】"categoryDelete?id=${categorie.id}"><span class="glyphicon glyphicon-remove"【可变】></span></a></td> </tr> </c:forEach> </tbody> <tfoot> <tr> <td colspan="6" align="center"> <!-- 点击超链接时,相当于提交了一个带有参数start的请求 --> <a href="categoryList?start=0">[首页]</a> <a href="categoryList?start=${pre}">[上一页]</a> <a href="categoryList?start=${next}">[下一页]</a> <a href="categoryList?start=${last}">[末页]</a> </td> </tr> </tfoot> </table>
效果五:可显示有序页
Servlet类
public class CategoryListServlet extends HttpServlet{ protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{ int start=0;//起始页的start值 int count=5;//【可变】 try {//如果请求中不带参数start,必须要进行try块的错误处理 start=Integer.parseInt(request.getParameter("start")); } catch (NumberFormatException e) { // TODO: handle exception } int total=new CategoryDAO().getTotal();//总数 int last=0;//末页的start值 if(0==total%count) last=total - count; else last=total - total % count; int page=0; if(0==total%count) page=total % count; else page=total % count+1; List<Category>categories=new CategoryDAO().list(start,count);//【可变】 request.setAttribute("last", last);//把count传递给jsp request.setAttribute("page", page);//把page传递给jsp request.setAttribute("count", count);//把count传递给jsp request.setAttribute("categories【可变】", categories);//把categories传递给jsp request.getRequestDispatcher("/admin/category/categoryList.jsp【可变】").forward(request, response); } }
JSP代码
<table class=【可变】"table table-striped table-bordered table-hover table-condensed"> <thead>【可变】 <tr class=【可变】"success"> <td>ID</td> <td>图片</td> <td>分类名称</td> <td>编辑</td> <td>删除</td> </tr> </thead> <tbody> <c:forEach items="${categories【可变】}" var="categorie【可变】"> <tr> <td>${categorie.id【可变】}</td> <td><img height="40px" src=【可变】"img/category/${categorie.id}.jpg"></td> <td>${categorie.name【可变】}</td> <td><a href=【可变】"categoryEdit?id=${categorie.id}"><span class="glyphicon glyphicon-edit"></span></a></td> <td><a href=【可变】"categoryDelete?id=${categorie.id}"><span class="glyphicon glyphicon-remove"></span></a></td> </tr> </c:forEach> </tbody> <tfoot> <tr> <td colspan="6" align="center"> <!-- 点击超链接时,相当于提交了一个带有参数start的请求 --> <a href=【可变】"categoryList?start=0">[1]</a> <c:forEach var="i" begin="2" end="${page-2}"> <a href=【可变】"categoryList?start=${(i-1)*count}">[${i}]</a> </c:forEach> <a href=【可变】"categoryList?start=${last}">[${page-1}]</a> </td> </tr> </tfoot> </table>
效果五:可显示首页、上一页、中间页、下一页、末页
Servlet类
public class CategoryListServlet extends HttpServlet{ protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{ int start=0;//起始页开始值 int count=5;//【可变】 try {//如果请求中不带参数start,必须要进行try块的错误处理 start=Integer.parseInt(request.getParameter("start")); } catch (NumberFormatException e) { // TODO: handle exception } int total=new CategoryDAO().getTotal();//总数 int last=0;//末页开始值 if(0==total%count) last=total - count; else last=total - total % count; int pre=start-count;//上一页开始值 pre=pre>0?pre:0;//边界处理 int next=start+count;//下一页开始值 next=next<last?next:last;//边界处理 int page=0;//总页数 if(0==total%count) page=total % count; else page=total % count+1; List<Category>categories=new CategoryDAO().list(start,count);//【可变】 request.setAttribute("pre", pre);//把pre传递给jsp request.setAttribute("next", next);//把next传递给jsp request.setAttribute("last", last);//把last传递给jsp request.setAttribute("page", page);//把page传递给jsp request.setAttribute("count", count);//把count传递给jsp request.setAttribute("categories【可变】", categories【可变】);//把categories传递给jsp request.getRequestDispatcher("/admin/category/categoryList.jsp"【可变】).forward(request, response); } }
JSP代码
<tfoot> <tr> <td colspan="6" align="center"> <!-- 点击超链接时,相当于提交了一个带有参数start的请求 --> <a href=【可变】"categoryList?start=0">[首页]</a> <a href="categoryList?start=${pre}">[上一页]</a> <!-- 中间页 --> <a href=【可变】"categoryList?start=0">[1]</a> <c:forEach var="i" begin="2" end="${page-2}"> <a href=【可变】"categoryList?start=${(i-1)*count}">[${i}]</a> </c:forEach> <a href=【可变】"categoryList?start=${last}">[${page-1}]</a> <!-- 中间页 --> <a href=【可变】"categoryList?start=${next}">[下一页]</a> <a href=【可变】"categoryList?start=${last}">[末页]</a> </td> </tr> </tfoot>