我有这个问题。我想为自定义选择一些数据创建 selectOneMenu。但它不起作用，我真的不知道为什么。我花了 cca 5 个小时来解决这个问题。我好绝望。所以我的一些代码：
但是当我从 selectonemenu 中选择一些项目时，selected_id 仍然是 0。仍然，仍然。我试图做几乎所有事情，但没有结果。
我试过这个：
<p:selectOneMenu value="#{medicinesBean.selectedBranch}" required="true" effect="fade" id="listComboBox">
<f:selectItems value="#{medicinesBean.branchesForComboBox}" var="itm" itemLabel="#{itm.name}" itemValue="#{itm.id}" />
</p:selectOneMenu>
Backing Bean class:
/* private members */
private ArrayList<BranchDTO> branchesForComboBox = new ArrayList<BranchDTO>();
private BranchDTO selectedBranch;
/* getter and setters ... */
我也用 SelectItem[] 模型试过这个，但结果是一样的。不行。
然后我试了一下：
<p:selectOneMenu value="#{medicinesBean.selected_id}" required="true" effect="fade" id="listComboBox">
<f:selectItem itemLabel="First" itemValue="1"/>
<f:selectItem itemLabel="Second" itemValue="2"/>
<f:selectItem itemLabel="Third" itemValue="3"/>
<f:selectItem itemLabel="Fouth" itemValue="4"/>
</p:selectOneMenu>
/* private members */
private int selected_id;
但仍然为 0。当我为 selectonemenu 使用类似值的对象时，总是返回空异常。所以我很乐意为此提供任何建议。谢谢
brw。支持 bean 是 ViewScoped 并且来自 DAO 的数据被正确返回，因此组件 selectonemenu 中会出现一些错误。
谢谢BalusC，所以这是我的实现
支持豆
/**
* @author Sajmon
*/
package OraclBeans;
import DTOs.PobockaDTO;
import DTOs.ZoznamLiekovDTO;
import EJBs.ZoznamLiekovEJB;
import java.io.Serializable;
import java.util.ArrayList;
import javax.annotation.PostConstruct;
import javax.ejb.EJB;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
@ManagedBean(name="zoznamLiekovBean")
@ViewScoped
public class ZoznamLiekovBean implements Serializable {
@EJB
private ZoznamLiekovEJB listOfMedicineEJB;
/* private members */
private ArrayList<ZoznamLiekovDTO> listOfMedicines;
private ArrayList<PobockaDTO> branchesForCombobox = new ArrayList<PobockaDTO>();
private ZoznamLiekovDTO selectedItem;
private PobockaDTO selectedBranch;
//private SelectItem[] branchesOptions;
//private SelectItem selectedOption;
private int selected_id;
public ZoznamLiekovBean() {
}
@PostConstruct
private void init() {
branchesForCombobox = listOfMedicineEJB.getBranches();
listOfMedicines = listOfMedicineEJB.getLists();
}
public void test() {
System.out.println("ID: " + selected_id);
}
/*
private SelectItem[] addItemsToOptions() {
SelectItem[] data = new SelectItem[branchesForCombobox.size()];
for (int i = 0; i < branchesForCombobox.size(); i++) {
data[i] = new SelectItem(branchesForCombobox.get(i).getId(), branchesForCombobox.get(i).getNazov());
}
return data;
}
*/
/* getters and setters */
/*
public SelectItem[] getBranchesOptions() {
return branchesOptions;
}
public void setBranchesOptions(SelectItem[] branchesOptions) {
this.branchesOptions = branchesOptions;
}
public void setSelectedOption(SelectItem selectedOption) {
this.selectedOption = selectedOption;
}
public SelectItem getSelectedOption() {
return selectedOption;
}
*/
public ArrayList<PobockaDTO> getBranchesForCombobox() {
return branchesForCombobox;
}
public void setBranchesForCombobox(ArrayList<PobockaDTO> branchesForCombobox) {
this.branchesForCombobox = branchesForCombobox;
}
public ArrayList<ZoznamLiekovDTO> getListOfMedicines() {
return listOfMedicines;
}
public void setListOfMedicines(ArrayList<ZoznamLiekovDTO> listOfMedicines) {
this.listOfMedicines = listOfMedicines;
}
public PobockaDTO getSelectedBranch() {
return selectedBranch;
}
public void setSelectedBranch(PobockaDTO selectedBranch) {
this.selectedBranch = selectedBranch;
}
public ZoznamLiekovDTO getSelectedItem() {
return selectedItem;
}
public void setSelectedItem(ZoznamLiekovDTO selectedItem) {
this.selectedItem = selectedItem;
}
public int getSelected_id() {
return selected_id;
}
public void setSelected_id(int selected_id) {
this.selected_id = selected_id;
}
}
EJB：
/**
* @author Sajmon
*/
package EJBs;
import DTOs.PobockaDTO;
import DTOs.ZoznamLiekovDTO;
import OraclDAO.OracleZoznamLiekovDAO;
import java.io.Serializable;
import java.util.ArrayList;
import javax.ejb.Stateless;
@Stateless
public class ZoznamLiekovEJB implements Serializable {
private OracleZoznamLiekovDAO dao = new OracleZoznamLiekovDAO();
public ArrayList<ZoznamLiekovDTO> getLists() {
return dao.getListOfMedicines();
}
public ArrayList<PobockaDTO> getBranches() {
return dao.getBranchesForCombobox();
}
}
道：
/**
* @author Sajmon
*/
package OraclDAO;
import DTOs.PobockaDTO;
import DTOs.ZoznamLiekovDTO;
import OraclDAOFactory.OracleDAOFactory;
import java.io.Serializable;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;
public class OracleZoznamLiekovDAO implements Serializable {
private String SELECT_ALL = "SELECT Z.id_zoznamu, P.nazov_pobocky, L.nazov_lieku FROM Zoznam_liekov Z "
+ "JOIN Pobocka P ON (Z.id_pobocky = P.id_pobocky)"
+ "JOIN Liek L ON (Z.id_lieku = L.id_lieku)";
private String SELECT_BRANCHES = "SELECT DISTINCT P.id_pobocky, P.nazov_pobocky FROM Zoznam_liekov Z JOIN Pobocka P ON (Z.id_pobocky = P.id_pobocky)";
public OracleZoznamLiekovDAO() {
}
public ArrayList<PobockaDTO> getBranchesForCombobox() {
ArrayList<PobockaDTO> data = new ArrayList<PobockaDTO>();
PobockaDTO item;
Connection con = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
con = OracleDAOFactory.getOracleDatabaseConnection();
ps = con.prepareStatement(SELECT_BRANCHES);
rs = ps.executeQuery();
while (rs.next()) {
item = new PobockaDTO();
item.setId(rs.getInt(1));
item.setNazov(rs.getString(2));
data.add(item);
}
System.out.println("Data imported to list successfully.");
}
catch (SQLException ex) {
Logger.getLogger(OracleZoznamLiekovDAO.class.getName()).log(Level.SEVERE, null, ex);
}
finally {
if (con != null) {
try {
con.close();
}
catch (SQLException ex) {
Logger.getLogger(OracleZoznamLiekovDAO.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
return data;
}
public ArrayList<ZoznamLiekovDTO> getListOfMedicines() {
ArrayList<ZoznamLiekovDTO> data = new ArrayList<ZoznamLiekovDTO>();
ZoznamLiekovDTO item;
Connection con = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
con = OracleDAOFactory.getOracleDatabaseConnection();
ps = con.prepareStatement(SELECT_ALL);
rs = ps.executeQuery();
while (rs.next()) {
item = new ZoznamLiekovDTO();
item.setId(rs.getInt(1));
item.getPobocka().setNazov(rs.getString(2));
item.getLiek().setNazov(rs.getString(3));
data.add(item);
}
System.out.println("List of Medicines imported successfully.");
}
catch (SQLException ex) {
Logger.getLogger(OracleZoznamLiekovDAO.class.getName()).log(Level.SEVERE, null, ex);
}
finally {
if (con != null) {
try {
con.close();
}
catch (SQLException ex) {
Logger.getLogger(OracleZoznamLiekovDAO.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
return data;
}
}
和 XHTML：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:p="http://primefaces.org/ui"
xmlns:f="http://java.sun.com/jsf/core">
<h:head>
<title>Zoznam liekov - prehľad</title>
<link rel="stylesheet" type="text/css" href="../style.css" />
</h:head>
<h:body>
<div id="out">
<h:form id="mainForm">
<p:selectOneMenu value="#{zoznamLiekovBean.selected_id}" required="true" effect="fade" id="zoznamComboBox">
<f:selectItems value="#{zoznamLiekovBean.branchesForCombobox}" var="itm" itemLabel="#{itm.nazov}" itemValue="#{itm.id}"/>
</p:selectOneMenu>
<p:commandButton immediate="true" styleClass="submitClass" value="Generuj zoznam" update="dialogText" actionListener="#{zoznamLiekovBean.test()}"/>
<p:dataTable style="width: 1100px" widgetVar="zoznamLiekovTable" selection="#{zoznamLiekovBean.selectedItem}" selectionMode="single" rowKey="#{item.id}" var="item" value="#{zoznamLiekovBean.listOfMedicines}" rows="5" rowsPerPageTemplate="5,10,15,20"
paginator="true" paginatorTemplate="{RowsPerPageDropdown} {FirstPageLink} {PreviousPageLink} {CurrentPageReport} {NextPageLink}">
<p:column>
<f:facet name="header">ID:</f:facet>
<h:outputText value="#{item.id}"/>
</p:column>
<p:column>
<f:facet name="header">Pobočka:</f:facet>
<h:outputText value="#{item.pobocka.nazov}"/>
</p:column>
<p:column>
<f:facet name="header">Liek:</f:facet>
<h:outputText value="#{item.liek.nazov}"/>
</p:column>
</p:dataTable>
<p:dialog widgetVar="test" showEffect="explode" hideEffect="explode">
<h:outputText id="dialogText" value="#{zoznamLiekovBean.selected_id}"/>
</p:dialog>
</h:form>
</div>
</h:body>
</html>