显示Hibernate / JPA导致JSF datatable的原因：java.lang.NumberFormatException：对于输入字符串：“[propertyname]” [英] Showing Hibernate/JPA results in JSF datatable causes: java.lang.NumberFormatException: For input string: "[propertyname]"

问题描述

最初我以下查询获取列表< Employee> ：

Query query = session.createQuery("select table1 from Table as table1");
this.employees = (List<Employee>) query.list();

这在下面的datatable中成功呈现：

This is successfully rendered in below datatable:

<p:dataTable var="employee" value="#{bean.employees}">
    <p:column id="name" headerText="Name">
        <h:outputText value="#{employee.name}" />
    </p:column>
    <p:column id="id" headerText="ID" >
        <h:outputText value="#{employee.id}" />
    </p:column>
</p:dataTable>

但是，当我尝试从2个表中检索它，如下所示：

However, when I try to retrieve it from 2 tables as below:

Query query = session.createQuery("select a.name, b.id from Table1 as a, Table2 as b"); 
this.employees = (List<Employee>) query.list();

它引发以下异常：

java.lang.NumberFormatException: For input string: "name"
    at java.lang.NumberFormatException.forInputString(Unknown source)
    at java.lang.Integer.parseInt(Unknown source)
    at java.lang.Integer.parseInt(Unknown source)
    at javax.el.ArrayELResolver.toInteger(ArrayELResolver.java:166)
    at javax.el.ArrayELResolver.getValue(ArrayELResolver.java:46)
    ...

这是如何造成的，如何我可以解决它吗？

How is this caused and how can I solve it?

推荐答案

您的Hibernate查询是实际返回一个列出< Object []> ，而不是列表< Employee> ，因为您在未选中的演员中错误地假设。

Your Hibernate query is actually returning a List<Object[]>, not a List<Employee> as you incorrectly assumed during the unchecked cast.

证据在堆栈跟踪中：

java.lang.NumberFormatException: For input string: "name"
    at java.lang.NumberFormatException.forInputString(Unknown source)
    at java.lang.Integer.parseInt(Unknown source)
    at java.lang.Integer.parseInt(Unknown source)
    at javax.el.ArrayELResolver.toInteger(ArrayELResolver.java:166)
    at javax.el.ArrayELResolver.getValue(ArrayELResolver.java:46)
    ...

ArrayELResolver 仅 涉及名称（因此，＃{employee} ）表示像 Object [] 不像javabean一样的数组 Bean 。 EL尝试使用名称通过索引获取数组项，这只能是像这样的整数＃{employee [0]} 为第一项。但是，字符串值name不能解析为整数，因此此异常。

The ArrayELResolver is only involved when the base of name (thus, the #{employee}) represents an array like Object[] not a javabean like Bean. EL is attempting to use the name to obtain the array item by index, which can only be an integer like so #{employee[0]} for the 1st item. However, the string value "name" is not parseable as an integer and hence this exception.

您有2解决此问题的选项：

You have 2 options to solve this problem:

• 更改JSF代码以期望 List< Object []> ; 。使用例如＃{employee [0]} ，＃{employee [1]} 等。

<p:dataTable var="employee" value="#{bean.employees}">
    <p:column id="name" headerText="Name">
        <h:outputText value="#{employee[0]}" />
    </p:column>
    <p:column id="id" headerText="ID" >
        <h:outputText value="#{employee[1]}" />
    </p:column>
</p:dataTable>

修复Hibernate查询以返回一个真实 列表< Employee> 。

• NumberFormatException for input String < a>

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