Question

我正在尝试使用Hibernate Criteria API运行SELECT查询，该API在下面的代码中定义。我检查了控制台，它似乎是查询运行正常。以下是我在SQL Query的控制台中获得的内容：

 public class Book
    {
        public Book()
        {

        }
        [Key]
        public int IdBook { get; set; }
        public string Title { get; set; }

        [ForeignKey("Author")]
        public int IdAuthor{ get; set; }
        public Author Author { get; set; }
        public ICollection<Ticket> Tickets { get; set; }
    }

但是在控制台的上面的SQL下面，我看到了错误：

  public class Ticket
    {
        public Ticket()
        {

        }

        [Key]
        public int IdTicket { get; set; }
        public DateTime BorrowingDate { get; set; }
        public DateTime EstimatedLandingDate { get; set; }
        public DateTime? LandingTime { get; set; }

        [ForeignKey("Book")]
        public int IdBook { get; set; }
        public Book Book { get; set; }
    }

以下方法中第50行是以下行：

package main

import (
    "context"
    "log"
    "os"
    "sync"
    "time"
)

type worker struct {
    wg   *sync.WaitGroup
    in   chan job
    quit context.Context
}

type job struct {
    message int
}

func main() {
    numberOfJobs := 50

    ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
    defer cancel()

    w := worker{
        wg:   &sync.WaitGroup{},
        in:   make(chan job),
        quit: ctx,
    }

    for i := 0; i < numberOfJobs; i++ {
        go func(i int) {
            w.in <- job{message: i}
        }(i)
    }

    counter := 0
    for {
        select {
        case j := <-w.in:
            counter++
            log.Printf("Received job %+v\n", j)
            // DO SOMETHING WITH THE RECEIVED JOB
            // WORKING ON IT
            x := j.message * j.message
            log.Printf("job processed, result %d", x)
        case <-w.quit.Done():
            log.Printf("Recieved quit, timeout reached.  Number of jobs queued: %d, Number of jobs complete: %d\n", numberOfJobs, counter)
            os.Exit(0)
        default:
            // TODO
        }
    }

}

以下方法在EmployeeDaoImpl java类中定义。

Hibernate: 
    select
        this_.VALUE_EMP_ID as y0_ 
    from
        EMPLOYEE_TOP_METADATA this_ 
    where
        this_.TESTING_ID=? 
        and this_.COMPANY_EMP_ID=?

这是我的实体班java.lang.ClassCastException: java.lang.Integer cannot be cast to abc.def.myproject.orm.EmployeeTopMetaData at abc.def.myproject.orm.dao.impl.EmpDaoImpl.insertEmployeeDetails(EmployeeDaoImpl.java:50)：

(EmployeeTopMetaData) session.createCriteria(EmployeeTopMetaData.class)

Answer 1

您的查询仅返回＆＃34; this_.VALUE_EMP_ID＆＃34;一个int值。

如果要返回EmployeeTopMetaData，则必须更改查询：

Hibernate: 
    select
        this_
    from
        EMPLOYEE_TOP_METADATA this_ 
    where
        this_.TESTING_ID=? 
        and this_.COMPANY_EMP_ID=?

但我建议如果你只需要VALUE_EMP_ID，那么只更改变量会更好。

           Integer empMetaData = 
                (Integer) session.createCriteria(EmployeeTopMetaData.class) // This is the line #50
                .setProjection(Projections.property("valueEmpId"))
                .add(Restrictions.eq("testingId", 1234))
                .add(Restrictions.eq("company_employee_id", 3345))
                .uniqueResult();

java.lang.ClassCastException：java.lang.Integer无法强制转换为abc.def.myproject.orm.EmployeeTopMetaData

1 个答案: