如何通过hibernate将空字符串传递给Date类型列

Question

I am trying to pass an empty string that is "" to a Date type column Logout_date through hibernate:

query.setParameter(3, "");

But an exception is thrown :

java.lang.String cannot be cast to java.util.Date.

How can I achieve this.?

EDIT:

String updq2 = "update TblUser a set loggedStatus = ? ,lockedStatus= ?,currentAttempts = ?,logoutDate = ? where upper(a.id)=?";//,lockedStatus= ?, currentAttempts = ?, logoutDate = ? where upper(a.id) = ?";
            Session newSession2=factory.openSession();
            Transaction tx1=newSession2.beginTransaction();
            Query query =newSession2.createQuery(updq2);
            query.setParameter(0, (byte)9);
            query.setParameter(1,"1" );
            query.setParameter(2, 0);
            query.setParameter(3, "");
            query.setParameter(4,  userName.toUpperCase());
query.executeUpdate();
tx1.commit();
newSession2.close();

Answer 1

1. If your inserting data to your database and the database allows null values for that column just don't set that parameter in your query. In this case it's automatically set to null .

2. If your having an update statement and want to set an existing value to null you could try something like that:

    query.setParameter(3, PreparedStatement.setNull()); 

Hope that helps!

EDIT:

    String updq2;
    bool isNull = false;
    //If your data is null and you want to set it null use this 
    if(yourDate == null)
    {
        updq2 = "update TblUser a set loggedStatus = ? ,lockedStatus= ?,currentAttempts = ?,logoutDate = NULL where upper(a.id)=?";//,lockedStatus= ?, currentAttempts = ?, logoutDate = ? where upper(a.id) = ?";
        isNull = true;
    } //If it isn't null and you want to set and value use this
    else
    {
        updq2 = "update TblUser a set loggedStatus = ? ,lockedStatus= ?,currentAttempts = ?,logoutDate = ? where upper(a.id)=?";//,lockedStatus= ?, currentAttempts = ?, logoutDate = ? where upper(a.id) = ?";

    } 

    Session newSession2=factory.openSession();
    Transaction tx1=newSession2.beginTransaction();
    Query query =newSession2.createQuery(updq2);
    query.setParameter(0, (byte)9);
    query.setParameter(1,"1" );
    query.setParameter(2, 0);

    if(isNull)
    {
         query.setParameter(3,  userName.toUpperCase());
    }
    else
    {
         query.setParameter(3, yourDataHere);
         query.setParameter(4,  userName.toUpperCase());
    }

Answer 2

The best practice would be You check if date is null. If null you should avoid adding parameter for null value of type date. Hibernate does not automatically convert string to date.