动态h：输入文本以支持jsf中的Bean数组[ClassCastException]

Question

I'm using JSF 2.0 I have a problem to set Values of inputTexts to a table of double.

I can do this :

<h:inputText value="#{myBean.table[0]}" /> 

But, I would like to do it in a loop like that:

<c:forEach var="i" begin="0" end="#{myBean.inputsNumber}">              
    <h:inputText  value="#{myBean.table[i]}" />     <br/>            
</c:forEach>   
<h:commandButton action="#{myBean.calculate}" value="Calculate" /> 
Result: #{myBean.result}

Here is my backing bean :

@ManagedBean
@SessionScoped
public class MyBean {

    private double[] table;
    private double result;

    public MyBean() {
        table = new double[100];
    }

    public void calculate() {
        for (int i = 0; i < table.length; i++) {
            result += table[i];
        }
    }

    public double[] getTable() {
        return table;
    }

    public int getInputsNumber() {
        return table.length;
    }

    public double getResult() {
        return result;
    }

}

I tried to bind all components to an array of HtmlInputText , but I could not solve it. i got this exception : ClassCastException

Answer 1

There are 2 problems:

1. The <c:forEach end> is inclusive. You need to take 1 off from it, otherwise you end up with ArrayIndexOutOfBoundsException when submitting.

    <c:forEach var="i" begin="0" end="#{myBean.inputsNumber - 1}"> 

   A better approach is however to just iterate over the array itself and get the index by varStatus .

    <c:forEach items="#{myBean.table}" varStatus="loop"> <h:inputText value="#{myBean.table[loop.index]}" /> </c:forEach> 

   ---

2. A double in EL is treated as Double , not as double . So you need Double[] instead of double[] , otherwise you end up with ClassCastException when submitting.

    private Double[] table;