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[英]How do i get custom post-processing after binding to a backing bean ? Java Server Faces
[英]Binding more than one input field to a backing bean property by using Java Server Faces?
假設我有一個月,日和年選擇。 每個選擇一個。 現在,我需要將它們綁定到單個后備bean屬性-java.util.Date。 我如何實現目標?
三種方式:
java.util.Calendar
使用三個getter和三個setter對其進行回退或中間操作。 Converter
,但是這會有點麻煩。 rich:calendar
類的第三方組件。 編輯:根據評論,這是選項2的樣子。
page.jsp
:
<h:form>
<h:selectOneMenu value="#{myBean.date}">
<f:converter converterId="datePartConverter" />
<f:attribute name="part" value="day" />
<f:selectItems value="#{myBean.days}" />
</h:selectOneMenu>
<h:selectOneMenu value="#{myBean.date}">
<f:converter converterId="datePartConverter" />
<f:attribute name="part" value="month" />
<f:selectItems value="#{myBean.months}" />
</h:selectOneMenu>
<h:selectOneMenu value="#{myBean.date}">
<f:converter converterId="datePartConverter" />
<f:attribute name="part" value="year" />
<f:selectItems value="#{myBean.years}" />
</h:selectOneMenu>
<h:commandButton value="submit" action="#{myBean.submit}"/>
<h:messages />
</h:form>
mypackage.MyBean
:
package mypackage;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import javax.faces.model.SelectItem;
public class MyBean {
private static List<SelectItem> days = new ArrayList<SelectItem>();
private static List<SelectItem> months = new ArrayList<SelectItem>();
private static List<SelectItem> years = new ArrayList<SelectItem>();
static {
// Just do your thing to fill them. Only ensure that those are Strings,
// else you'll need to change the type in Converter accordingly.
for (int i = 1; i <= 31; i++) days.add(new SelectItem(String.valueOf(i)));
for (int i = 1; i <= 12; i++) months.add(new SelectItem(String.valueOf(i)));
for (int i = 2000; i <= 2020; i++) years.add(new SelectItem(String.valueOf(i)));
}
private Date date;
public void submit() {
// Print submitted date to stdout.
System.out.println("Submitted date: " + date);
}
public List<SelectItem> getDays() {
return days;
}
public List<SelectItem> getMonths() {
return months;
}
public List<SelectItem> getYears() {
return years;
}
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
}
mypackage.DatePartConverter
:
package mypackage;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;
import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import javax.faces.component.UIInput;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.convert.ConverterException;
public class DatePartConverter implements Converter {
public Object getAsObject(FacesContext context, UIComponent component, String value) {
String part = (String) component.getAttributes().get("part");
Date date = null;
if (context.getRenderResponse()) {
// Convert any default/selected date for display.
Date selectedDate = (Date) ((UIInput) component).getValue();
if (selectedDate != null) {
if (("day".equals(part) && new SimpleDateFormat("d").format(selectedDate).equals(value))
|| ("month".equals(part) && new SimpleDateFormat("M").format(selectedDate).equals(value))
|| ("year".equals(part) && new SimpleDateFormat("yyyy").format(selectedDate).equals(value)))
{
date = selectedDate;
}
}
} else {
// Convert submitted date after submit.
Map<String, Object> map = context.getExternalContext().getRequestMap();
if ("day".equals(part)) {
map.put("DatePartConverter.day", value); // Save until we have all parts.
} else if ("month".equals(part)) {
map.put("DatePartConverter.month", value); // Save until we have all parts.
} else if ("year".equals(part)) {
String day = (String) map.get("DatePartConverter.day");
String month = (String) map.get("DatePartConverter.month");
String dateString = String.format("%s-%s-%s", day, month, value);
try {
date = new SimpleDateFormat("d-M-yyyy").parse(dateString);
} catch (ParseException e) {
throw new ConverterException(new FacesMessage(e.getMessage()), e);
}
}
}
return date;
}
}
public String getAsString(FacesContext context, UIComponent component, Object value) {
// Not relevant here. Just return SelectItem's value.
return (String) value;
}
faces-config.xml
<converter>
<converter-id>datePartConverter</converter-id>
<converter-class>mypackage.DatePartConverter</converter-class>
</converter>
<managed-bean>
<managed-bean-name>myBean</managed-bean-name>
<managed-bean-class>mypackage.MyBean</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
</managed-bean>
請注意,沒有Validator
,並且SimpleDateFormat
默認為lenient
。 因此,例如選擇11月31日將產生12月1日。 如果要對此進行警告,則可能需要自己實現DatePartValidator
。
說“綁定”和“支持bean”時,應該參考以下內容:
<h:inputText binding="#{myBean.myTextField}" />
並在bean中包含private UIInput
。
如果真是這樣-不,您不能那樣綁定。 好吧,我不確定您在技術上是否可以-但這肯定會產生意想不到的效果。
但是,如果要定位托管bean屬性 ,則可以例如:
<h:inputText value="#{myBean.myProperty.day}" />
<h:inputText value="#{myBean.myProperty.year}" />
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