我在一个jsp查询页面中放置了三个查询条件:楼号,层号,房间号。现在我用楼号,层号,房间号查询以及用楼号,层号查询来达到显示不同的查询结果。在查询结果页面中,我用
if("房间号为空")
{
显示用楼号,层号为查询条件的查询结果;
}
else{
显示用楼号,层号,房间号为查询条件的查询结果;
}
在调试时,当未输入房间号时,点击查询按钮时,if中的语句并不执行。执行的仍是else中的内容。
这种情况如何处理。谢谢!
if("房间号为空")
{
显示用楼号,层号为查询条件的查询结果;
}
else{
显示用楼号,层号,房间号为查询条件的查询结果;
}
在调试时,当未输入房间号时,点击查询按钮时,if中的语句并不执行。执行的仍是else中的内容。
这种情况如何处理。谢谢!
}
<%
String distN=request.getParameter("distNum");
String roomN=request.getParameter("roomNum");
String floorN=request.getParameter("floorNum");
%>
if(roomN==null) {
<%
try {
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
String url = "jdbc:mysql://localhost/xuesheng?user=root&password=wanzhang&Unicode=true&characterEncoding=gb2312";
Connection con = DriverManager.getConnection(url);
Statement stmt=con.createStatement();
ResultSet rs;
String SqlQue="SELECT deviceuse.roomNum,devNum,useCt FROM relation,district,deviceuse where deviceuse.roomNum='"
+roomN+"' and district.distNum='"
+distN+"' and relation.floorNum='"
+floorN+"'";
//out.print(SqlQue);
rs = stmt.executeQuery(SqlQue);
while(rs.next()){
%>
<tr class="normal">
<td width="88"><%=rs.getString("roomNum")%></td>
<td width="171"><%=rs.getString("devNum")%></td>
<td width="166"><%=rs.getString("useCt")%></td>
</tr>
<% }
stmt.close();
con.close();
}
catch(SQLException ex){out.print(ex.toString());}
%>
<% } else {
<%
try {
Class.forName("org.gjt.mm.mysql.Driver").newInstance();
String url = "jdbc:mysql://localhost/xuesheng?user=root&password=wanzhang&Unicode=true&characterEncoding=gb2312";
Connection con = DriverManager.getConnection(url);
Statement stmt=con.createStatement();
ResultSet rs;
String SqlQue="SELECT deviceuse.roomNum,devNum,useCt FROM relation,district,deviceuse where deviceuse.roomNum='"
+roomN+"' and district.distNum='"
+distN+"' and relation.floorNum='"
+floorN+"'";
//out.print(SqlQue);
rs = stmt.executeQuery(SqlQue);
while(rs.next()){
%>
<tr class="normal">
<td width="88"><%=rs.getString("roomNum")%></td>
<td width="171"><%=rs.getString("devNum")%></td>
<td width="166"><%=rs.getString("useCt")%></td>
</tr>
<% }
stmt.close();
con.close();
}
catch(SQLException ex){out.print(ex.toString());}
%>
}%>
}