如何在JSF Datatable中生成动态列？

Question

想有下面的数据表结构：

+--------------------------------------------------------------+ 
|  dynamic  |  dynamic  |  dynamic  | 
|--------------------------------------------------------------| 
| col1 | col2 | col3 | col1 | col2 | col3 | col1 | col2 | col3 |  
|--------------------------------------------------------------| 
| data | data | data | data | data | data | data | data | data | 

的原因是，我不知道有多少列有显示，直到我要求的数据库。 col1，col2，col3中的列总是相同的。

我试着用下面的数据表：

<h:form id="form">  
     <h:panelGrid columns="3" style="margin:10px 0"> 
      <p:outputLabel for="template" value="Adid:" style="font-weight:bold"/> 
      <p:inputText id="template" value="#{reportingView.adId}" size="50"/> 
      <p:commandButton update="kpi_table" actionListener="#{reportingView.updateColumns}" value="Create Data" process="@parent" icon="ui-icon-refresh" oncomplete="PF('carsTable').clearFilters()"/> 
     </h:panelGrid> 

     <p:dataTable id="reportingTable" var="pi" value="#{reportingView.indicators}" widgetVar="indicatorTable" filteredValue="#{reportingView.filteredValues}">      
      <p:columns value="#{reportingView.columns}" var="column" columnIndexVar="colIndex" sortBy="#{pi[column.property]}" > 
       <f:facet name="header"> 
        <h:outputText value="#{column.header}" /> 
       </f:facet> 

       <p:columnGroup type="header"> 
        <p:row> 
         <p:column headerText="1" /> 
         <p:column headerText="2" /> 
         <p:column headerText="3" /> 
        </p:row> 
       </p:columnGroup> 


      </p:columns> 
     </p:dataTable> 
    </h:form> 

但是，正如你可以想像，它不会工作 - columnGroup似乎被忽略。 我建议将动态结构与静态列组合起来是不可能的。有没有人解决类似的问题？

非常感谢

Answer 1

JSF有Value binding和Component binding。通常，我们使用value binding。 根据我的经验，我使用Component binding来生成动态组件并通过程序进行控制。 （例如：喜欢你）。

How does the 'binding' attribute work in JSF?

对于你的问题，检查并尝试下面的示例程序。

MockDb.java

它是报头和子报头的数据。它可能来自数据库。

import java.util.ArrayList; 
import java.util.List; 

public class MockDb { 
    public static List<Header> getHeaderList() { 
     List<Header> headerList = new ArrayList<Header>(); 

     List<SubCol> subColList_1 = new ArrayList<SubCol>(); 
     subColList_1.add(new SubCol("Col 1", "Data 1")); 
     subColList_1.add(new SubCol("Col 2", "Data 2")); 
     subColList_1.add(new SubCol("Col 3", "Data 3")); 
     headerList.add(new Header("Header 1", subColList_1)); 

     List<SubCol> subColList_2 = new ArrayList<SubCol>(); 
     subColList_2.add(new SubCol("Col 1", "Data 1")); 
     subColList_2.add(new SubCol("Col 2", "Data 2")); 
     subColList_2.add(new SubCol("Col 3", "Data 3")); 
     headerList.add(new Header("Header 2", subColList_2)); 


     List<SubCol> subColList_3 = new ArrayList<SubCol>(); 
     subColList_3.add(new SubCol("Col 1", "Data 1")); 
     subColList_3.add(new SubCol("Col 2", "Data 2")); 
     subColList_3.add(new SubCol("Col 3", "Data 3")); 
     subColList_3.add(new SubCol("Col 4", "Data 4")); 
     headerList.add(new Header("Header 3", subColList_3)); 


     List<SubCol> subColList_4 = new ArrayList<SubCol>(); 
     subColList_4.add(new SubCol("Col 1", "Data 1")); 
     subColList_4.add(new SubCol("Col 2", "Data 2")); 
     subColList_4.add(new SubCol("Col 3", "Data 3")); 
     subColList_4.add(new SubCol("Col 4", "Data 4")); 
     subColList_4.add(new SubCol("Col 5", "Data 5")); 
     headerList.add(new Header("Header 4", subColList_4)); 

     return headerList; 
    } 

    public static List<DataValue> getValueList() { 
     /*Create 5 rows for data array for 15 columns*/ 
     List<DataValue> valueList = new ArrayList<DataValue>(); 
     for(int i=1; i <=5; i++) { 
      DataValue data = new DataValue("1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15"); 
      valueList.add(data); 
     } 
     return valueList; 
    } 
} 

Header.java

public class Header { 
    private String name; 
    private List<SubCol> subColList; 

    public Header(){ 
    } 

    public Header(String name, List<SubCol> subColList) { 
     this.name = name; 
     this.subColList = subColList; 
    } 
    //getter & setter 
} 

SubCol.java

public class SubCol { 
    private String name; 
    private String data; 

    public SubCol() { 
    } 

    public SubCol(String name, String data) { 
     this.name = name; 
     this.data = data; 
    } 
    //getter & setter 
} 

DataValue.java

public class DataValue { 
    private String data1; 
    private String data2; 
    private String data3; 
    private String data4; 
    private String data5; 
    private String data6; 
    private String data7; 
    private String data8; 
    private String data9; 
    private String data10; 
    private String data11; 
    private String data12; 
    private String data13; 
    private String data14; 
    private String data15; 

    public DataValue(){ 
    } 

    public DataValue(String data1, String data2, String data3, String data4, String data5, String data6, String data7, 
      String data8, String data9, String data10, String data11, String data12, String data13, String data14, 
      String data15) { 
     this.data1 = data1; 
     this.data2 = data2; 
     this.data3 = data3; 
     this.data4 = data4; 
     this.data5 = data5; 
     this.data6 = data6; 
     this.data7 = data7; 
     this.data8 = data8; 
     this.data9 = data9; 
     this.data10 = data10; 
     this.data11 = data11; 
     this.data12 = data12; 
     this.data13 = data13; 
     this.data14 = data14; 
     this.data15 = data15; 
    } 
    //getter & Setter 
} 

DynamicColumnBean.java

import java.util.List; 

import javax.annotation.PostConstruct; 
import javax.el.ELContext; 
import javax.el.ExpressionFactory; 
import javax.el.ValueExpression; 
import javax.faces.application.Application; 
import javax.faces.bean.ManagedBean; 
import javax.faces.bean.ViewScoped; 
import javax.faces.component.html.HtmlOutputText; 
import javax.faces.context.FacesContext; 

import org.primefaces.component.column.Column; 
import org.primefaces.component.columngroup.ColumnGroup; 
import org.primefaces.component.datatable.DataTable; 
import org.primefaces.component.row.Row; 

import com.kbzmai.skyfly.common.Header; 
import com.kbzmai.skyfly.common.MockDb; 
import com.kbzmai.skyfly.common.SubCol; 

@ManagedBean(name = "DynamicColumnBean") 
@ViewScoped 
public class DynamicColumnBean { 

    private DataTable myDataTable; 

    public DataTable getMyDataTable() { 
     return myDataTable; 
    } 

    public void setMyDataTable(DataTable myDataTable) { 
     this.myDataTable = myDataTable; 
    } 

    @PostConstruct 
    public void init() { 
     myDataTable = new DataTable(); 
     myDataTable.setValue(MockDb.getValueList()); 
     myDataTable.setVar("mydata"); 

     ColumnGroup columnGroup = new ColumnGroup(); 
     myDataTable.getChildren().add(columnGroup); 
     columnGroup.setType("header"); 
     List<Header> headerList = MockDb.getHeaderList(); 

     /*Create Column for Header*/   
     Row headerRow = new Row(); 
     columnGroup.getChildren().add(headerRow); 
     for(Header header : headerList) { 
      Column column = new Column(); 
      /*Make sure to set column span*/ 
      column.setColspan(header.getSubColList().size()); 
      headerRow.getChildren().add(column); 
      column.setHeaderText(header.getName()); 
     } 

     FacesContext fc = FacesContext.getCurrentInstance(); 
     Application application = fc.getApplication(); 
     ExpressionFactory ef = application.getExpressionFactory(); 
     ELContext elc = fc.getELContext(); 

     /*Create Column for Sub Column of current header*/  
     Row subColRow = new Row(); 
     columnGroup.getChildren().add(subColRow); 
     for(Header header : headerList) { 
      for(SubCol subCol : header.getSubColList()) { 
       Column column = new Column(); 
       subColRow.getChildren().add(column); 
       column.setHeaderText(subCol.getName()); 
      } 
     } 

     /*Create data row for 15 columns*/  
     for(int i=1; i <= 15; i++) { 
      ValueExpression valueExp = ef.createValueExpression(elc, "#{mydata.data" + i + "}", Object.class); 
      HtmlOutputText output = (HtmlOutputText)application.createComponent(HtmlOutputText.COMPONENT_TYPE); 
      output.setValueExpression("value", valueExp); 
      Column dataColumn = new Column(); 
      dataColumn.getChildren().add(output); 
      myDataTable.getChildren().add(dataColumn); 
     } 
    } 
} 

dynamicColumnTest.xhtml

<p:dataTable binding="#{DynamicColumnBean.myDataTable}"/>  

结果：