public List<T> getAllById(int pageCount,int pageNum,int id) {
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
List<T> list = new ArrayList<T>();
try {
conn = this.getConn();
stmt = conn.prepareStatement("select * from(select t.*,rownum rk from testTablet order by id) where rk<=? and rk>? ");
stmt.setInt(1, pageNum*pageCount);
stmt.setInt(2, (pageNum-1)*pageCount);
rs = stmt.executeQuery();
while(rs.next()){
T t= new T();
list.add(t);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
this.closeAll(rs, stmt, conn);
}
return list;
}
int pageSize = 2;
int count = messBiz.pageDiv(user.getUserid());
int p =1;
if(request.getParameter("p")!=null){
p = Integer.parseInt(request.getParameter("p"));
}
int num = (int)Math.ceil(count/pageSize);
int prePage = p==1?1:p-1;
int nexPage = p==num?num:p+1;
..........
共<%=count %>条<%=num %>页第<%=p %>页
<a href="listMsg.jsp?p=<%=prePage %>">上一页</a>
<a href="listMsg.jsp?p=<%=nexPage %>">下一页</a>
2、发件人下拉列表的选择
<form action="doPost.jsp" method="post" id="myForm">
<table border="1" >
<tr><td>收件人</td>
<td>
<select name = "recId">
<%for(Users user:userList){ %>
<option value="<%=user.getUserid() %>"><%=user.getUserName() %></option>
<%} %>
</select>
<%if(request.getParameter("id")!=null) {%>
<script type="text/javascript">myForm.recId.value='<%=Integer.parseInt(request.getParameter("id"))%>'</script>
<%} %>
</td></tr>
<tr><td>标题</td><td><input type="text" name="title"/></td></tr>
<tr><td><input type="text" name="content"/></td></tr>
</table>
<input type="submit" name="reply" value="发送"/>
<input type="reset" name="summint" value="清空" />
</form>
3、使用按钮实现页面的跳转并传递参数
<input type="button" value="回复" onclick="window.location.href='post.jsp?id=${mess.senderId}'"/>
<input type="button" value="删除" onclick="window.location.href='doDelete.jsp?id=${mess.messageId}'"/>
4、对于奇偶行显示不同的北京颜色(使用的是JSTL标签)
<table>
<tr>
<td></td><td>状态</td><td>标题</td><td>发件人</td><td>时间</td><td>是否删除</td>
</tr>
<c:forEach var="mess" items="${messList}" step="1" varStatus="staus">
<c:choose >
<c:when test="${staus.index%2==0}" ><c:set var="color" value="#FAEBD7"></c:set></c:when>
<c:otherwise ><c:set var="color" value="#FFEBCD"></c:set></c:otherwise>
</c:choose>
<tr bgcolor=${color} }>
<td>${staus.index }</td>
<td>${mess.isRead}</td>
<td><a href="showMsg.jsp?id=${mess.messageId }">${mess.title }</a></td>
<td>${mess.senderId }</td>
<td>${mess.time }</td>
<td><input type="button" value="删除" onclick="window.location.href='doDelete.jsp?id=${mess.messageId }'"/></td>
</tr>
</c:forEach>
</table>
5、退出使用时
session.removeAttribute("user");
response.sendRedirect("login.jsp");
6、设置字节码类型的Filter
public class codeFilter implements Filter {
public void destroy() {
// TODO Auto-generated method stub
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
request.setCharacterEncoding("utf-8");
chain.doFilter(request, response);
}
public void init(FilterConfig filterConfig) throws ServletException {
// TODO Auto-generated method stub
}
}
6、记录用户登录的Filter
public class SessionFilter implements Filter {
public void destroy() {
// TODO Auto-generated method stub
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest)request;
HttpServletResponse res = (HttpServletResponse)response;
String url = req.getRequestURI();
if(url.endsWith("login.jsp")||url.endsWith("doLogin.jsp")){
chain.doFilter(request, response);
}
else{
if(req.getSession().getAttribute("user")==null){
res.sendRedirect("login.jsp");
}
else{
chain.doFilter(request, response);
}
}
}
public void init(FilterConfig filterConfig) throws ServletException {
// TODO Auto-generated method stub
}
}
7、关于DAO中方法的命名规则
增删改分为使用insert、delete、update
查使用的是get
8、关于我的BaseDao
public class BaseDao {
public Connection getConn(){
Connection conn = null;
try {
Context ic = new InitialContext();
DataSource source = (DataSource) ic.lookup("java:comp/env/jdbc/message");
conn = source.getConnection();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NamingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
public void closeAll(ResultSet rs ,PreparedStatement stmt,Connection conn){
try {
if(rs != null)
rs.close();
stmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
public int executeUpdate(String sql,Object[] obj){
Connection conn = getConn();
PreparedStatement stmt = null;
int ret = 0;
try {
stmt = conn.prepareStatement(sql);
for(int i=0;i<obj.length;i++){
stmt.setObject(i+1, obj[i]);
}
ret = stmt.executeUpdate();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
closeAll(null,stmt,conn);
}
return ret;
}
}
9、关于表连接后属性的问题
可以再实体类中多加几个属性来满足表连接后的视图的问题。