受管bean的多个实例 [英] Multiple instances of managed bean
问题描述
我正在使用素面选项卡来显示多个输入表单.问题是，有时我需要实例化相同形式的2.当然，它们都使用相同的Managed Bean，这会使第一个初始化形式的输入用相同的数据覆盖另一个形式.我需要能够在每种表单中放入不同的数据，然后共同提交它们.每个表格都会进入一个列表，然后继续进行计算.我一直在阅读范围作用域作用域作用域，但是唯一起作用的作用域是"Sessioned".会话仅允许一个Managed Bean实例并将表单数据放入列表中，请求，查看范围"既不将数据分别放入列表中也不保存数据.受管Bean是可序列化的，并且处于会话范围内.我读过另一篇文章，但它们不起作用.有什么想法吗?
I'm using prime-faces Tabs to display multiple input forms. The problem is, there are times when I need to instantiate 2 of the same form. They both of course use the same Managed Bean which causes the input of the first initialized form to override the other with the same data. I need to be able to put different data in each form and submit both of them collectively. Each form goes into a list and forwarded on for calculation. I've been reading scope scope scope scope but the only scope that works somewhat is "Sessioned". Session only allows one instance of the Managed Bean and places the form data into the list, "Request, View scope" Doesn't place the data into the list respectively nor does it hold the data. The Managed Bean is serializable and in sessioned scope. I've read the other post and they don't work. Any ideas?
后备豆
@ManagedBean
@SessionScoped
public class RequestCalculation {
private CalculationRequest calcReq;
private List<ViewTabs> formTabs;
private String id;
private boolean calcButton;
public RequestCalculation() {
calcReq = new CalculationRequest();
formTabs = new ArrayList<ViewTabs>();
calcButton = false;
}
public String loadForm(TcsBase loadForm) {
id = loadForm.getId();
ViewTabs tab = new ViewTabs();
tab.setFormTitle("Form".concat(id));
tab.setFormPage("Form".concat(id).concat(".xhtml"));
formTabs.add(0, tab);
calcReq.getFormCollection().add(0, loadForm);
loadCalcButton();
return "Main";
}
public void loadCalcButton() {
if (formTabs.isEmpty())
isCalcButton();
else {
calcButton = true;
}
}
public void onTabClosed(TabCloseEvent e) {
TabView tabView = (TabView) e.getComponent();
int closingTabIndex = tabView.getChildren().indexOf(e.getTab());
removeForm(closingTabIndex);
formTabs.remove(closingTabIndex);
loadCalcButton();
}
public void removeForm(int index) {
TcsBase formIndex = calcReq.getFormCollection().get(index);
String formId = formIndex.getId();
// Creates a new instance of the selected form
FacesContext fc = FacesContext.getCurrentInstance();
fc.getELContext().getELResolver()
.setValue(fc.getELContext(), null, "form".concat(formId), null);
calcReq.getFormCollection().remove(index);
formTabs.remove(index);
}
public String calculate() {
CalculateService service = new CalculateService();
CalculatorInterface calculateInterface = service.getCalculatePort();
XStream xstream = new XStream(new StaxDriver());
xstream.registerConverter(new JodaTimeConverter());
// Here is where the client request (input) is converted to an Xml
// string before going
// to the Web Service
String xml = xstream.toXML(calcReq);
String request = calculateInterface.calculate(xml);
// Here the response back from the Web Service is converted back from
// Xml to a string
// to be displayed to the user in Xhtml
calcReq = (CalculationRequest) xstream.fromXML(request);
FacesContext fc = FacesContext.getCurrentInstance();
for (int i = 0; i < calcReq.getFormCollection().size(); i++) {
TcsBase newFrm = calcReq.getFormCollection().get(i);
String frmId = newFrm.getId();
fc.getELContext()
.getELResolver()
.setValue(fc.getELContext(), null, "form".concat(frmId),
newFrm);
}
return null;
}
public List<ViewTabs> getFormTabs() {
return formTabs;
}
public void setFormTabs(List<ViewTabs> formTabs) {
this.formTabs = formTabs;
}
public boolean isCalcButton() {
return calcButton;
}
public void setCalcButton(boolean calcButton) {
this.calcButton = calcButton;
}
}
** HTML菜单**
**Html Menu **
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:p="http://primefaces.org/ui">
<head>
</head>
<f:view>
<h:body>
<h:commandLink action="#{requestCalculation.loadForm(formA)}" value="FormA" /> <br/>
<h:commandLink action="#{requestCalculation.loadForm(formB)}" value="FormB" /> <br/><br/><br/>
</h:body>
</f:view>
</html>
HTML主页
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:p="http://primefaces.org/ui"
xmlns:c="http://java.sun.com/jsp/jstl/core">
<f:view>
<h:head>
<title> TCS </title>
</h:head>
<h:form >
<p:layout style="min-width:400px;min-height:700px " >
<p:layoutUnit position="north" style="text-align:center">
<p style="text-align:center; font-size:28px">Tax Computation Service</p>
</p:layoutUnit>
<p:layoutUnit header="Menu" position="west" style="min-width:190px; min-height:50px; ">
<p:panelMenu>
<p:submenu label="Forms">
<p:submenu label="Individual Forms">
<p:menuitem>
<ui:include src="Menu.xhtml" />
</p:menuitem>
</p:submenu>
</p:submenu>
</p:panelMenu>
</p:layoutUnit>
<p:layoutUnit position="center" >
<p:tabView onTabShow="focus" widgetVar="tabView">
<p:ajax event="tabClose" listener="#{requestCalculation.onTabClosed}"/>
<c:forEach items="#{requestCalculation.formTabs}" var="listItem">
<p:tab title="#{listItem.formTitle}" closable="true" >
<ui:include src="#{listItem.formPage}" />
</p:tab>
</c:forEach>
</p:tabView>
<p:panelGrid columns="0" >
<p:commandButton value="Calculate" action = "#{requestCalculation.calculate}" ajax="false" rendered="#{requestCalculation.calcButton}" />
</p:panelGrid>
</p:layoutUnit>
</p:layout>
</h:form>
</f:view>
</html>
FormA Html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:p="http://primefaces.org/ui">
<f:view>
<h:head>
<title> FormA</title>
</h:head>
<h:body>
<p:focus />
<p:panelGrid id="panelGridA" columns="2">
<p:outputLabel value="Form ID: " style="width: 725px" />
<p:outputLabel value="#{formA.id}" />
<p:outputLabel value="4. . . " style="width: 725px" />
<p:inputText id="input1" style="text-align:right" value="#{formA.line4}" converter="bdNullableConverter" onfocus="this.select()"/>
<p:outputLabel value="5. . . . . . . " style="width: 725px" />
<p:inputText style="text-align:right" value="#{formA.line5}" converter="bdNullableConverter" onfocus="this.select()" />
<p:outputLabel value="6. . . . . . . . " style="width: 725px" />
<p:outputLabel value="#{formA.line6}" converter="bdNullableConverter" />
</p:panelGrid>
</h:body>
</f:view>
</html>
推荐答案
而不是尝试使用托管Bean的多个实例，而是使用 ONE 托管Bean，该托管Bean通过以下方式访问类的多个实例:例如哈希图或数组列表或您要使用的任何内容.就像您在普通的旧Java编程中一样.您不能有两个名称相同的变量:
Instead of trying to use multiple instances of a managed bean, use ONE managed bean that gives access to multiple instances of a class via e.g. a hashmap or arraylist or whatever you want to use. Just like you would in plain old java programming. You cannot have two variables with the same name:
@ViewScoped
@Named
public class RequestCalculations {
Map<String, RequestCalculation> hm;
@PostConstruct
public init() {
hm = new HashMap<>();
// prepopulate if known upfront
hm.put("1", new RequestCalculation());
hm.put("2", new RequestCalculation());
}
public HashMap<String, RequestCalculation> getCalculations() {
return hm;
}
}
然后使用选项卡的tabIndex作为哈希图(或数组列表)的键.然后在您的xhtml中执行类似的操作
Then use the tabIndex of the tab as the key to the hashmap (or an array list). And in your xhtml do something like
#{requestCalculations.calculations[myTabIndex]}
如果您需要在包含中使用此参数，则可能需要通过包含参数将其传递给包含(如我想的那样)
You might need to pass this on to the include via a include param if you need this IN the include (as I think you do)
这篇关于受管bean的多个实例的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
