我有一个 bean“Player”,当我在 selectOneMenu 中选择一个值时,我想“切换”到数据库中匹配的 bean。
我已将 bean 发送回中的选择一个菜单
public List<Player> getAllPlayers() { }
已将下拉列表更新为此。
<h:selectOneMenu value="#{servicePlayer.myPlayer.combinedName}"
converter="playerConverter" id="playerList">
<f:selectItems value="#{servicePlayer.allPlayers}" var="player"
itemLabel="#{player.combinedName}" itemValue="#{player.id}" />
</h:selectOneMenu>
但我仍然无法将 ID 发送到转换器。它将发送玩家的名字。
@FacesConverter(value = "playerConverter")
public class PlayerConverter implements Converter {
@Override
public Object getAsObject(FacesContext context, UIComponent component, String value) {
if (value == null) {
return null;
}
long idValue;
try {
idValue = Long.parseLong(value);
}
catch (NumberFormatException ex)
{
return null;
}
ServicePlayer servicePlayer = context.getApplication()
.evaluateExpressionGet(context, "#{servicePlayer}",
ServicePlayer.class);
Player player = servicePlayer.getPlayerByID(idValue);
return player;
}
@Override
public String getAsString(FacesContext arg0, UIComponent arg1, Object value) {
String string = null;
if (value instanceof Player) {
string = ((Player) value).getFirstName();
}
return string;
}
}
public class ServicePlayer {
private static final String PERSISTENCE_UNIT_NAME = "BowlingFacelets";
public static EntityManagerFactory factory;
Player myPlayer;
public Player getMyPlayer() {
return myPlayer;
}
public void setMyPlayer(Player myPlayer) {
this.myPlayer = myPlayer;
}
public List<Player> getAllPlayers() {
if (factory == null) {
factory = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
}
EntityManager em = factory.createEntityManager();
//Order by the matchdate.
//Query q = em.createQuery("select t from DBTest t");
Query q = em.createQuery("select t from Player t");
List<Player> players = q.getResultList();
for (Player aPlayer : players) {
System.out.println(aPlayer);
}
System.out.println("Size: " + players.size());
em.close();
return players;
}
public Player getPlayerByID(long id) {
if (factory == null) {
factory = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
}
EntityManager em = factory.createEntityManager();
//Query q = em.createQuery("select t from Player t where t.name = '" + playerName + "'");
//List<Player> players = q.getResultList();
Player currentPlayer = em.find(Player.class, id);
return currentPlayer;
}
}
最佳答案
我认为您误解了 selectOneMenu 的 value 属性所指的含义。它的用途就像在所有其他输入组件中存储用户输入的位置(或从中获取现有值的位置)。
检查http://www.jsftoolbox.com/documentation/help/12-TagReference/core/f_selectItems.html 。您需要根据 f:select 项上的“var”属性设置键和值对,否则 JSF 无法真正了解您想要对 Player 对象执行什么操作。
因此,鉴于键/值对(键进入您设置的值属性,值显示给用户)已就位,并且如果您使用player.id作为值,则可以获取基于该 ID 的用户。
关于java - 在 JSF 中选择 "switch"bean 的最佳方法,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/20629975/