Hibernate自定义UserType不起作用

本文介绍了Hibernate自定义UserType不起作用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 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 @ Basic 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.