显示Hibernate/JPA导致JSF数据表原因:java.lang.NumberFormatException:对于输入字符串:"[propertyname]"

Question

我最初的以下查询获得List<Employee>:

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

这在以下数据表中成功呈现:

<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个表中检索它时,如下所示:

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

它抛出以下异常:

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)
    ...

这是怎么造成的,我该如何解决？

Answer 1

您的Hibernate查询实际上是返回a List<Object[]>,而不是List<Employee>在未经检查的强制转换期间错误地假设的.

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)
    ...

的ArrayELResolver是仅当的碱参与name(因而,#{employee})表示像阵列Object[]不象一个JavaBean Bean.EL正在尝试使用name索引来获取数组项,索引只能是#{employee[0]}第1项的整数.但是,字符串值"name"不能作为整数进行解析,因此也是此异常.

您有2个选项可以解决此问题:

• 改变JSF代码以期望a List<Object[]>.使用例如#{employee[0]},#{employee[1]}等等.

  <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查询以返回真实 List<Employee>.

也可以看看:

• 输入String的NumberFormatException