Java 无法以正确的顺序显示SQL中的数据，HTML JSP_Java_Sql_Jsp_Servlets_Model View Controller

Java 无法以正确的顺序显示SQL中的数据，HTML JSP

java sql jsp servlets model-view-controller

Java 无法以正确的顺序显示SQL中的数据，HTML JSP,java,sql,jsp,servlets,model-view-controller,Java,Sql,Jsp,Servlets,Model View Controller,我目前正在做一个小组项目，我们应该处理建筑和房间之间的关系。这种关系是OnetoMany，我们目前能够显示来自sql的相关数据，但我们无法按预期在外观良好的电子表格或表格中显示它。我们希望将建筑物和房间整理成一张表格，每个房间都显示与相关建筑物的连接。我们如何将HTML代码放入ShowRooms.jsp中，以获得用户选择的建筑物的所有房间，然后将该建筑物的所有房间显示在一个漂亮的表格中？在这种状态下，我们从sql数据库中获取数据，但数据是直线的，而不是通过一个表来获取，该表将每个房间连接到相关的

我目前正在做一个小组项目，我们应该处理建筑和房间之间的关系。这种关系是OnetoMany，我们目前能够显示来自sql的相关数据，但我们无法按预期在外观良好的电子表格或表格中显示它。我们希望将建筑物和房间整理成一张表格，每个房间都显示与相关建筑物的连接。我们如何将HTML代码放入ShowRooms.jsp中，以获得用户选择的建筑物的所有房间，然后将该建筑物的所有房间显示在一个漂亮的表格中？在这种状态下，我们从sql数据库中获取数据，但数据是直线的，而不是通过一个表来获取，该表将每个房间连接到相关的建筑。提前谢谢

这是我们的代码：建筑：

@Entity
@Table(name = "Building")
public class Building {
private String bname;
private List<Room> rooms; // Building can have many Rooms

@Id
@Column(name = "Bname")
public String getBname() {
return bname;
}

public void setBname(String bname) {
this.bname = bname;
}

@OneToMany(mappedBy = "building", fetch = FetchType.EAGER)
public List<Room> getRooms() {
return rooms;
}

public void setRooms(List<Room> rooms) {
this.rooms = rooms;
}   
}

建筑EAO：

@Stateless
public class BuildingEAOImpl implements BuildingEAOImplLocal {
@PersistenceContext(unitName = "LabEJBSql")
private EntityManager em;

public BuildingEAOImpl() {
// TODO Auto-generated constructor stub
}

public Building findByBname(String bname) {
return em.find(Building.class, bname);
}
}

正面：

@Stateless
public class Facade implements FacadeRemote, FacadeLocal {
@EJB
BuildingEAOImplLocal BuildingEAO;
@EJB
RoomEAOImplLocal RoomEAO;

public Facade() {
// TODO Auto-generated constructor stub
}

public List<Room> findRoomsByBname(String bname) { 
 return RoomEAO.findByBname(bname); 
 }
}

SERVLET：

@WebServlet("/TestClientServlet")
public class TestClientServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
@EJB
private FacadeLocal facade;

/**
* @see HttpServlet#HttpServlet()
*/
public TestClientServlet() {
super();
// TODO Auto-generated constructor stub
}

protected void doGet(HttpServletRequest request,
    HttpServletResponse response) throws ServletException, IOException {

PrintWriter out = response.getWriter();
out.println("TestClientServlet-doGet");
out.close();

}

protected void doPost(HttpServletRequest request,
    HttpServletResponse response) throws ServletException, IOException {

String url = null;
// Get hidden field
String operation = request.getParameter("operation");

if (operation.equals("showrooms")) {
    String bname = request.getParameter("txtBname");

    List<Room> r = facade.findRoomsByBname(bname);
    request.setAttribute("rooms", r);
    url = "/ShowRooms.jsp";
} else if (operation.equals("searchbuilding")) {
    System.out.println("TestClientServlet-searchbuilding");
    url = "/SearchBuilding.jsp";
} else {
    url = "/SearchBuilding.jsp";
}
System.out.println(url);

RequestDispatcher dispatcher = getServletContext()
        .getRequestDispatcher(url);
dispatcher.forward(request, response);
}
*/
}

SEARCHBUILDING.JSP：

<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=ISO-
8859-1"> 
<title>Search Building</title> 
</head> 
<body> 
<form action="/BuildRoomClientProject/TestClientServlet" method="post"> 

<table cellspacing="0" cellpadding="0" border="0" align="left"> 
<tr> 
<td><h2>Search Building:</h2></td> 
</tr> 
<tr> 
<td> 

<input type= "text" name= "txtBname" size ="25" maxlength="25">
<input type="submit" name="submit" value="Search" /> 
</td> 
<td></td> 
</tr> 
</table> 

<input name="operation" value="showrooms" type="hidden"> 

</form> 
</body> 
</html>

SHOWROOMS.JSP：

<%@ page contentType="text/html;charset=windows-1252"%> 
<%@ page import = "org.ics.ejb.Building" %> 
<%@ page import = "org.ics.ejb.Room" %> 
<%@ page import = "org.ics.ejb.RoomId" %> 
<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 
<title> 
Show Rooms
</title> 
</head> 
<body> 
<h2> 
Rooms: 
</h2> 
<%List<Room> r = (List<Room>)request.getAttribute("rooms"); %>
<% for (Room r1 : r){
out.println(r1.getBname() + " " + r1.getId().getrcode());
}%> 
<p>
</p>
<form action="/BuildRoomClientProject/TestClientServlet" method="post"> 
<input type="submit" name="submit" value="Tillbaka"> 
<input name="operation" value="searchbuilding" type="hidden"> 
</form> 
</body> 
</html>

对于jpql，您不使用GROUPBY和GROUPBY指令组合吗？然后，对于得到的每个表条目，呈现bname=BuildingName？？作为第一排。然后将检索到的列表呈现为表，一个简短的示例可能是：

<table>
     <c:forEach var="o" items="${objects}">
        <tr>
            <td>${o.bname}</td>
            <td>${o.id}</td>
            <td>${o.name}</td>
            <td>${o.descriptio}</td>   
        </tr>
    </c:forEach>
</table>

事实上，我刚刚发现了这一点：搜索jsp、listview、table

您应该使用的。

<table>
     <c:forEach var="o" items="${objects}">
        <tr>
            <td>${o.bname}</td>
            <td>${o.id}</td>
            <td>${o.name}</td>
            <td>${o.descriptio}</td>   
        </tr>
    </c:forEach>
</table>