Jsf 2 未从primefaces backing bean中的下拉列表中获取选定值
嗨,我已经建立了两个连续的下拉列表,一个在init()方法中初始化,另一个在第一个选择的基础上填充 命令按钮用于使用两个选定值进行处理,奇怪的是,所选值的Setter被调用了两次(第二次设置为空..正如我在调试中发现的那样..我需要了解我为什么会得到空值 myPage.xhtmlJsf 2 未从primefaces backing bean中的下拉列表中获取选定值,jsf-2,primefaces,Jsf 2,Primefaces,嗨,我已经建立了两个连续的下拉列表,一个在init()方法中初始化,另一个在第一个选择的基础上填充 命令按钮用于使用两个选定值进行处理,奇怪的是,所选值的Setter被调用了两次(第二次设置为空..正如我在调试中发现的那样..我需要了解我为什么会得到空值 myPage.xhtml <p:selectOneMenu id="dbList" value="#{backingBean.selectedConnection}" style="width:200px">
<p:selectOneMenu id="dbList"
value="#{backingBean.selectedConnection}"
style="width:200px">
<p:ajax listener="#{backingBean.onConnectionChange()}"
update="aliasList" />
<f:selectItem itemLabel="Select" itemValue="#{backingBean.selectedConnection}"
noSelectionOption="false" />
<f:selectItems value="#{backingBean.connectionsTypeList}" />
</p:selectOneMenu>
<p:outputLabel for="aliasList" value="Connection Alias" />
<p:selectOneMenu id="aliasList"
value="#{backingBean.aliasSelected}" style="width:200px">
<f:selectItem itemLabel="Select" itemValue="#{backingBean.aliasSelected}"
noSelectionOption="false"/>
<f:selectItems value="#{backingBean.connectionsList}" />
</p:selectOneMenu>
<p:commandButton value="myButton"
actionListener="#{backingBean.myMethod()}"
id="myButton" />
backingBean.java
@ManagedBean
@ViewScoped
public class BackingBean implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private ArrayList<String> connectionsList;
private String aliasSelected;
private String selectedConnection;
private ArrayList<String> connectionsTypeList;
@PostConstruct
public void init() {
// Initialize the connection alias drop down here
this.connectionsTypeList = getConnectionTypeList();
this.connectionsList=new ArrayList<String>();
}
public void onConnectionChange() {
System.out.println("In Connection Change, populating aliases");
getConnectionDBList();
}
public String getAliasSelected() {
return aliasSelected;
}
//Dont know why this is called twice on button click and second time value set is blank
public void setAliasSelected(String aliasSelected) {
this.aliasSelected = aliasSelected;
}
public ArrayList<String> getConnectionsList() {
return connectionsList;
}
public void setConnectionsList(ArrayList<String> connectionsList) {
this.connectionsList = connectionsList;
}
public String getSelectedConnection() {
return selectedConnection;
}
public void setSelectedConnection(String selectedConnection) {
this.selectedConnection = selectedConnection;
}
public ArrayList<String> getConnectionsTypeList() {
return connectionsTypeList;
}
public void setConnectionsTypeList(ArrayList<String> connectionsTypeList) {
this.connectionsTypeList = connectionsTypeList;
}
public void myMethod() {
System.out.println("selected Alias is "+aliasSelected);
System.out.println("selected connection is "+selectedConnection);
}
}
@ManagedBean
@视域
公共类BackingBean实现了可序列化{
/**
*
*/
私有静态最终长serialVersionUID=1L;
私有ArrayList连接列表;
选择私有字符串别名;
私有字符串选择连接;
私有ArrayList连接类型列表;
@施工后
公共void init(){
//初始化此处的连接别名下拉列表
this.ConnectionTypeList=getConnectionTypeList();
this.connectionList=newArrayList();
}
连接更改()上的公共无效{
System.out.println(“连接更改,填充别名”);
getConnectionBlist();
}
公共字符串getAliasSelected(){
返回选定的别名;
}
//不知道为什么在单击按钮时调用两次,而第二次值集为空
已选择公共空集合别名(已选择字符串别名){
this.aliasSelected=aliasSelected;
}
公共阵列列表getConnectionsList(){
返回连接列表;
}
public void setConnectionsList(ArrayList connectionsList){
this.connectionsList=connectionsList;
}
公共字符串getSelectedConnection(){
返回selectedConnection;
}
public void setSelectedConnection(字符串selectedConnection){
this.selectedConnection=selectedConnection;
}
公共阵列列表getConnectionsTypeList(){
返回connectionsTypeList;
}
public void setConnectionsTypeList(ArrayList connectionsTypeList){
this.connectionsTypeList=connectionsTypeList;
}
公共方法(){
System.out.println(“所选别名为”+所选别名);
System.out.println(“所选连接为”+所选连接);
}
}
primefaces新手,请帮助回答:“第二次设置为空..正如我在调试中发现的那样”
发生这种情况是因为我意识到我将同一属性指向两个ui组件..如..同一页面中的两个下拉列表链接到了支持bean的同一属性..愚蠢的错误..因此第二次调用setter..使用空值..因为它没有为第二个ui组件初始化您选择使用相同的值对于SelectOne菜单和
f:selectItem
的外观和感觉都很奇怪(我猜您是在尝试预选默认值?没有必要)。你可能想摆脱它。还要确保bean在渲染过程中没有被破坏和重新创建-检查@PostConstruct
方法没有被调用多次