Hibernate自定义UserType不起作用

问题描述

我创建了一个UserType（见下文）来处理我们的mySQL数据库中的情况，我们已经将空日期保存为0000-00-00 00:00:00。

当我尝试用dispDT的null（参见下文）持久化实体时，它会生成此异常：javax.persistence.PersistenceException：org.hibernate.PropertyValueException：not-null属性引用null或瞬态值：myEntity.dispDt通过在MySQLTimeStampUserType中的每个方法中设置一个断点，我可以看到它调用了deepCopy方法，并且从不调用nullSafeSet方法。我认为nuyllSafeSet方法的全部重点是让我在继续使用之前操纵这个值。我做错了什么？

实体注解

  @Basic可选= false）
 @Column（name =disp_dt）
 @Type（type =mypackage.MySQLTimeStampUserType）
 // @Temporal（TemporalType.TIMESTAMP）
 private日期显示; 
  

用户类型class

  public class MySQLTimeStampUserType implements UserType {
 
 private static final int [] SQL_TYPES = {Types.TIMESTAMP}; 
 
 public int [] sqlTypes（）{
 return SQL_TYPES; 
} 
 
 public Class returnedClass（）{
 return Date.class; 
 
 $ b $ public boolean equals（Object x，Object y）throws HibernateException {
 if（x == y）{
 return true; 
} else if（x == null || y == null）{
 return false; 
} else {
 return x.equals（y）; 
 
 
 
 $ b public int hashCode（Object arg0）throws HibernateException {
 throw new UnsupportedOperationException（Not supported yet。）; 
} 
 $ b $ public Object nullSafeGet（ResultSet resultSet，String [] names，Object owner）throws HibernateException，SQLException {
 //如果日期为0000-00-00 00： 00:00返回null，否则返回时间戳
日期结果= null;如果（！resultSet.wasNull（））{
 if（！resultSet.getString（names [0]）。equals（0000-00-00 00:00:00））{
 result = resultSet.getDate（names [0]）; 
} 
} 
返回结果; 
 
 $ b $ public void nullSafeSet（PreparedStatement statement，Object value，int index）throws HibernateException，SQLException {
 //如果日期为null，则将值设置为0000-00 -00 00:00:00否则保存时间戳
 if（value == null）{
 statement.setString（index，0000-00-00 00:00:00）; 
} else {
 statement.setTimestamp（index，（Timestamp）value）; 
} 
 
} 
 
 public Object deepCopy（Object value）throws HibernateException {
 return value; 
} 
 
 public boolean isMutable（）{
 return false; 
 
 $ b $ public public Serializable disassemble（Object value）throws HibernateException {
 throw new UnsupportedOperationException（not supported yet。）; 
} 
 
 public Object assemble（Serializable cached，Object owner）throws HibernateException {
 throw new UnsupportedOperationException（Not supported yet。）; 
} 
 
 public Object Object（Object original，Object target，Object owner）throws HibernateException {
 return original; 
 
 
 $ / code $ / pre 
 
解决方案
问题不在于你的UserType  - 这是因为你已经声明你的属性为非null（使用 optional =false），但您将其设置为null。
 
 
 
说，我会小心在deepCopy /汇编/反汇编方法中返回原始值。 java.util.Date  是可变的，您可能会在那里寻求麻烦。
 
I've created a UserType (see below) to handle a situation in our mySQL database where we've been saving null dates as 0000-00-00 00:00:00.

When I try and persist my entity with a null for dispDT (see below) it generates this exception: "javax.persistence.PersistenceException: org.hibernate.PropertyValueException: not-null property references a null or transient value: myEntity.dispDt"

By setting a breakpoint in every method in MySQLTimeStampUserType I can see it calls the deepCopy method and never calls the nullSafeSet method. I thought the whole point of the nuyllSafeSet method was to allow me to manipulate the value before persisting it. What am I doing wrong?

Entity Annotations
@Basic(optional = false)
@Column(name = "disp_dt")
@Type(type = "mypackage.MySQLTimeStampUserType")
//    @Temporal(TemporalType.TIMESTAMP)
private Date dispDt;
User Type class
public class MySQLTimeStampUserType implements UserType {

private static final int[] SQL_TYPES = {Types.TIMESTAMP};

public int[] sqlTypes() {
    return SQL_TYPES;
}

public Class returnedClass() {
    return Date.class;
}

public boolean equals(Object x, Object y) throws HibernateException {
    if (x == y) {
        return true;
    } else if (x == null || y == null) {
        return false;
    } else {
        return x.equals(y);
    }

}

public int hashCode(Object arg0) throws HibernateException {
    throw new UnsupportedOperationException("Not supported yet.");
}

public Object nullSafeGet(ResultSet resultSet, String[] names, Object owner) throws HibernateException, SQLException {
    // if the date is 0000-00-00 00:00:00 return null, else return the timestamp
    Date result = null;
    if (!resultSet.wasNull()) {
        if (!resultSet.getString(names[0]).equals("0000-00-00 00:00:00")) {
            result = resultSet.getDate(names[0]);
        }
    }
    return result;
}

public void nullSafeSet(PreparedStatement statement, Object value, int index) throws HibernateException, SQLException {
    // if the date is null set the value to "0000-00-00 00:00:00" else save the timestamp
    if (value == null) {
        statement.setString(index, "0000-00-00 00:00:00");
    } else {
        statement.setTimestamp(index,(Timestamp) value);
    }

}

public Object deepCopy(Object value) throws HibernateException {
    return value;
}

public boolean isMutable() {
    return false;
}

public Serializable disassemble(Object value) throws HibernateException {
    throw new UnsupportedOperationException("Not supported yet.");
}

public Object assemble(Serializable cached, Object owner) throws HibernateException {
    throw new UnsupportedOperationException("Not supported yet.");
}

public Object replace(Object original, Object target, Object owner) throws HibernateException {
    return original;
}
}
 解决方案 
Your problem is not with your UserType - it's with the fact that you've declared your property as not-null (using @Basic optional="false") and yet you're setting it to null.
That said, I'd be careful about returning the original value in deepCopy / assemble / disassemble methods. java.util.Date is mutable and you may be asking for trouble there.
                        
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