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分页效果图：
实现思路：
数据访问层
传入每页想显示的数据，得到最大页数
// 获取最大页数
public int getMaxPage(String username, int num) {
int result = 0;// 查询结果
int PageNum = 0;
// 得到数据库连接
Connection conn = DBConnection.getConnection();
// 聚合查询得到需要显示的数据
String sql = "select count(*) as count from book where user=? or user=?";
try {
// 预编译
PreparedStatement ps = conn.prepareStatement(sql);
ps.setString(1, username);
ps.setString(2, "");
ResultSet rs = ps.executeQuery();
while (rs.next()) {
result = rs.getInt("count");
}
// 防止算术异常
if (num == 0) {
PageNum = 1;
return PageNum;
}
// 能够整除情况
if (result % num == 0) {
PageNum = result / num;
} else {
PageNum = result / num + 1;
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return PageNum;
}
// 获取分页数据
public List<Book> Limit(String username, int page, int num) {
List<Book> list = new ArrayList<Book>();
// 得到数据库连接
Connection conn = DBConnection.getConnection();
String sql = "select * from book where user=? or user=? limit ?,?";
try {
PreparedStatement ps = conn.prepareStatement(sql);
ps.setString(1, username);
ps.setString(2, "");
ps.setInt(3, (page - 1) * num);// (查询页数-1)*每页记录数
ps.setInt(4, num);
// 查询得到结果集
ResultSet rs = ps.executeQuery();
while (rs.next()) {
int id = rs.getInt("id");
String name = rs.getString("name");
double price = rs.getDouble("price");
String info = rs.getString("info");
String img_url = rs.getString("img_url");
String borrow_date = rs.getString("borrow_date");
String user = rs.getString("user");
Book book = new Book(id, name, price, info, img_url,
borrow_date, user);
list.add(book);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return list;
}
业务逻辑层
准备好方法：
// 分页得到共多少页
public int getMaxPage(String username, int num) {
return bdao.getMaxPage(username, num);
}
// 分页数据
public List<Book> Limit(String username, int page, int num) {
List<Book> list = new ArrayList<Book>();
list = bdao.Limit(username, page, num);
return list;
}控制层
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
// 得到登录的用户名
HttpSession session = request.getSession();
String username = session.getAttribute("username").toString();
//分页每页记录数
int num=3;
//得到分页的最大页数，每页3条数据
int PageNum=bservice.getMaxPage(username, num);
//得到请求的页数
int page=Integer.parseInt(request.getParameter("page"));
//准备数据
List<Book> list = bservice.Limit(username, page, num);
request.setAttribute("booklist", list);
request.setAttribute("PageNum", PageNum);
request.setAttribute("page", page);
// 转发
request.getRequestDispatcher("WEB-INF/jsp/main.jsp").forward(request,
response);
}
视图层
<table width="700" border="1" align="center" cellpadding="1"
cellspacing="0">
<tr align="center" bgcolor="#CCFFFF">
<td><a href="listbook.do?page=1">首页</a></td>
<!-- 显示第一页数据时，上页不可点击 -->
<c:choose>
<c:when test="${page ==1 }">
<td>上页</td>
</c:when>
<c:otherwise>
<td><a href="listbook.do?page=${page-1 }"> 上页</a></td>
</c:otherwise>
</c:choose>
<!-- 显示最后一页数据时，下页不可点击 -->
<c:choose>
<c:when test="${page ==PageNum }">
<td>下页</td>
</c:when>
<c:otherwise>
<td><a href="listbook.do?page=${page+1 }"> 下页</a></td>
</c:otherwise>
</c:choose>
<td><a href="listbook.do?page=${PageNum }">末页</a></td>
<td>跳转到第 <input name="page" type="text" id="page" size="1"
value="${page }" /> 页 <input type="button" name="turn" id="button2"
value="确定" onclick="turn(${PageNum})" /></td>
<td>${page }/${PageNum}页</td>
</tr>
</table>
<script type="text/javascript">
function turn(maxpage) {
var index = document.getElementById("page").value;
/* 当输入页数为0或负数时，显示第一页 */
if (index <= 0) {
index = 1;
}
/* 当输入页数大于等于最后一页时，显示最后一页 */
if(index>=maxpage){
index=maxpage;
}
window.location.href = 'listbook.do?page=' + index;
}
</script>
登录成功后，默认显示第一页数据
// 转发到登录成功页面
request.getRequestDispatcher("listbook.do?page=1").forward(request,
response);
