java - JPA 失败(java.lang.IllegalArgumentException)

Question

我有一个网络服务明显无缘无故地失败了。有时它会执行，有时它会提供此错误，我似乎无法弄清楚，因为查询实际上是有意义的......

java.lang.IllegalArgumentException: You have attempted to set a value of type class org.models.Employees for parameter currentEmployeeID with expected type of class org.models.Employees from query string SELECT b.carID FROM Cars b WHERE b.currentEmployeeID = :currentEmployeeID .
    at org.eclipse.persistence.internal.jpa.QueryImpl.setParameterInternal(QueryImpl.java:932)

在键入的查询中，

Employees emp = new Employees(1)

TypedQuery<Integer> query = em.createQuery("SELECT b.carID FROM Cars b WHERE b.currentEmployeeID = :currentEmployeeID", Integer.class);
            query.setParameter("currentEmployeeID",emp);

正如我所说，有时它会起作用。有时当我重新启动服务时，它会连续失败。

如果我说 currentEmployeeID 作为整数而不是对象员工，它将提供一个更清晰的错误，我明白为什么..(比如，我正在尝试为参数设置整数类型的值......)

Answer 1

当您等待标识符时，传递给该方法的参数似乎是雇员类型。请尝试以下操作:

Employees emp = new Employees(1)

TypedQuery<Integer> query = em.createQuery("SELECT b.carID FROM Cars b WHERE b.currentEmployeeID = :currentEmployeeID", Integer.class);
            query.setParameter("currentEmployeeID",emp.getId());