知识大全 Hibernate如何映射枚举类型
Posted 类型
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问题
Java BO类Gender是枚举类型 想在数据库中存成字符串格式 如何编写hbm xml？
[java] view plaincopyprint?
public enum Gender
UNKNOWN( Unknown )
MALE( Male )
FEMALE( Female );
private String key;
private Gender(final String key)
this key = key;
public getGender(String key)
for (Gender gender : Gender values())
if (key euqals(gender getKey()))
return gender;
throw new NoSuchElementException(key);
public enum Gender
UNKNOWN( Unknown )
MALE( Male )
FEMALE( Female );
private String key;
private Gender(final String key)
this key = key;
public getGender(String key)
for (Gender gender : Gender values())
if (key euqals(gender getKey()))
return gender;
throw new NoSuchElementException(key);
使用UserType
[java] view plaincopyprint?
public class GenderUserType implements UserType
private static int[] typeList = Types VARCHAR;
/*
* Return the SQL type codes for the columns mapped by this type
* The codes are defined on <tt>java sql Types</tt> */
/**设置和Gender类的sex属性对应的字段的SQL类型 */
public int[] sqlTypes()
return typeList;
/*The class returned by <tt>nullSafeGet()</tt> */
/** 设置GenderUserType所映射的Java类 Gender类 */
public Class returnedClass()
return Gender class;
/** 指明Gender类是不可变类 */
public boolean isMutable()
return false;
/*
* Return a deep copy of the persistent state stopping at entities and at
* collections It is not necessary to copy immutable objects or null
* values in which case it is safe to simply return the argument
*/
/** 返回Gender对象的快照 由于Gender类是不可变类 因此直接将参数代表的Gender对象返回 */
public Object deepCopy(Object value)
return (Gender)value;
/** 比较一个Gender对象是否和它的快照相同 */
public boolean equals(Object x Object y)
//由于内存中只可能有两个静态常量Gender实例
//因此可以直接按内存地址比较
return (x == y);
public int hashCode(Object x)
return x hashCode();
/*
* Retrieve an instance of the mapped class from a JDBC resultset Implementors
* should handle possibility of null values
*/
/** 从JDBC ResultSet中读取key 然后返回相应的Gender实例 */
public Object nullSafeGet(ResultSet rs String[] names Object owner)
throws HibernateException SQLException
//从ResultSet中读取key
String sex = (String) Hibernate STRING nullSafeGet(rs names[ ]);
if (sex == null) return null;
//按照性别查找匹配的Gender实例
try
return Gender getGender(sex);
catch (java util NoSuchElementException e)
throw new HibernateException( Bad Gender value: + sex e);
/*
* Write an instance of the mapped class to a prepared statement Implementors
* should handle possibility of null values
* A multi column type should be written to parameters starting from <tt>index</tt>
*/
/** 把Gender对象的key属性添加到JDBC PreparedStatement中 */
public void nullSafeSet(PreparedStatement st Object value int index)
throws HibernateException SQLException
String sex = null;
if (value != null)
sex = ((Gender)value) getKey();
Hibernate String nullSafeSet(st sex index);
/*
* Reconstruct an object from the cacheable representation At the very least this
* method should perform a deep copy if the type is mutable (optional operation)
*/
public Object assemble(Serializable cached Object owner)
return cached;
/*
* Transform the object into its cacheable representation At the very least this
* method should perform a deep copy if the type is mutable That may not be enough
* for some implementations however; for example associations must be cached as
* identifier values (optional operation)
*/
public Serializable disassemble(Object value)
return (Serializable)value;
/*
* During merge replace the existing (target) value in the entity we are merging to
* with a new (original) value from the detached entity we are merging For immutable
* objects or null values it is safe to simply return the first parameter For
* mutable objects it is safe to return a copy of the first parameter For objects
* with ponent values it might make sense to recursively replace ponent values
*/
public Object replace(Object original Object target Object owner)
return original;
public class GenderUserType implements UserType
private static int[] typeList = Types VARCHAR;
/*
* Return the SQL type codes for the columns mapped by this type
* The codes are defined on <tt>java sql Types</tt> */
/**设置和Gender类的sex属性对应的字段的SQL类型 */
public int[] sqlTypes()
return typeList;
/*The class returned by <tt>nullSafeGet()</tt> */
/** 设置GenderUserType所映射的Java类 Gender类 */
public Class returnedClass()
return Gender class;
/** 指明Gender类是不可变类 */
public boolean isMutable()
return false;
/*
* Return a deep copy of the persistent state stopping at entities and at
* collections It is not necessary to copy immutable objects or null
* values in which case it is safe to simply return the argument
*/
/** 返回Gender对象的快照 由于Gender类是不可变类 因此直接将参数代表的Gender对象返回 */
public Object deepCopy(Object value)
return (Gender)value;
/** 比较一个Gender对象是否和它的快照相同 */
public boolean equals(Object x Object y)
//由于内存中只可能有两个静态常量Gender实例
//因此可以直接按内存地址比较
return (x == y);
public int hashCode(Object x)
return x hashCode();
/*
* Retrieve an instance of the mapped class from a JDBC resultset Implementors
* should handle possibility of null values
*/
/** 从JDBC ResultSet中读取key 然后返回相应的Gender实例 */
public Object nullSafeGet(ResultSet rs String[] names Object owner)
throws HibernateException SQLException
//从ResultSet中读取key
String sex = (String) Hibernate STRING nullSafeGet(rs names[ ]);
if (sex == null) return null;
//按照性别查找匹配的Gender实例
try
return Gender getGender(sex);
catch (java util NoSuchElementException e)
throw new HibernateException( Bad Gender value: + sex e);
/*
* Write an instance of the mapped class to a prepared statement Implementors
* should handle possibility of null values
* A multi column type should be written to parameters starting from <tt>index</tt>
*/
/** 把Gender对象的key属性添加到JDBC PreparedStatement中 */
public void nullSafeSet(PreparedStatement st Object value int index)
throws HibernateException SQLException
String sex = null;
if (value != null)
sex = ((Gender)value) getKey();
Hibernate String nullSafeSet(st sex index);
/*
* Reconstruct an object from the cacheable representation At the very least this
* method should perform a deep copy if the type is mutable (optional operation)
*/
public Object assemble(Serializable cached Object owner)
return cached;
/*
* Transform the object into its cacheable representation At the very least this
* method should perform a deep copy if the type is mutable That may not be enough
* for some implementations however; for example associations must be cached as
* identifier values (optional operation)
*/
public Serializable disassemble(Object value)
return (Serializable)value;
/*
* During merge replace the existing (target) value in the entity we are merging to
* with a new (original) value from the detached entity we are merging For immutable
* objects or null values it is safe to simply return the first parameter For
* mutable objects it is safe to return a copy of the first parameter For objects
* with ponent values it might make sense to recursively replace ponent values
*/
public Object replace(Object original Object target Object owner)
return original;
然后再hbm xml中定义映射关系
[] view plaincopyprint?
<hibernate mapping package= default lazy= true default cascade= save update merge persist >
<typedef name= Gender class= alpha hibernate GenderUserType >
<property name= gender type= Gender >
<column name= GENDER not null= true >
</column>
</property>
<hibernate mapping package= default lazy= true default cascade= save update merge persist >
<typedef name= Gender class= alpha hibernate GenderUserType >
<property name= gender type= Gender >
<column name= GENDER not null= true >
</column>
</property>
延伸
为每个枚举类型定义一个UserType是比较麻烦的 可以定义一个抽象类
例如扩展下例即可适用于所有保存为index的枚举类型
[java] view plaincopyprint?
public abstract class OrdinalEnumUserType<E extends Enum<E>> implements UserType
protected Class<E> clazz;
protected OrdinalBasedEnumUserType(Class<E> clazz)
this clazz = clazz;
private static final int[] SQL_TYPES = Types NUMERIC;
public int[] sqlTypes()
return SQL_TYPES;
public Class<?> returnedClass()
return clazz;
public E nullSafeGet(ResultSet resultSet String[] names Object owner)
throws HibernateException SQLException
//Hibernate STRING nullSafeGet(rs names[ ])
int index = resultSet getInt(names[ ]);
E result = null;
if (!resultSet wasNull())
result = clazz getEnumConstants()[index];
return result;
public void nullSafeSet(PreparedStatement preparedStatement
Object value int index) throws HibernateException SQLException
if (null == value)
preparedStatement setNull(index Types NUMERIC);
else
//Hibernate String nullSafeSet(st sex index);
preparedStatement setInt(index ((E)value) ordinal());
public Object deepCopy(Object value) throws HibernateException
return value;
public boolean isMutable()
return false;
public Object assemble(Serializable cached Object owner)
throws HibernateException
return cached;
public Serializable disassemble(Object value) throws HibernateException
return (Serializable)value;
public Object replace(Object original Object target Object owner)
throws HibernateException
return original;
public int hashCode(Object x) throws HibernateException
return x hashCode();
public boolean equals(Object x Object y) throws HibernateException
if (x == y)
return true;
if (null == x || null == y)
return false;
return x equals(y);
public abstract class OrdinalEnumUserType<E extends Enum<E>> implements UserType
protected Class<E> clazz;
protected OrdinalBasedEnumUserType(Class<E> clazz)
this clazz = clazz;
private static final int[] SQL_TYPES = Types NUMERIC;
public int[] sqlTypes()
return SQL_TYPES;
public Class<?> returnedClass()
return clazz;
public E nullSafeGet(ResultSet resultSet String[] names Object owner)
throws HibernateException SQLException
//Hibernate STRING nullSafeGet(rs names[ ])
int index = resultSet getInt(names[ ]);
E result = null;
if (!resultSet wasNull())
result = clazz getEnumConstants()[index];
return result;
public void nullSafeSet(PreparedStatement preparedStatement
Object value int index) throws HibernateException SQLException
if (null == value)
preparedStatement setNull(index Types NUMERIC);
else
//Hibernate String nullSafeSet(st sex index);
preparedStatement setInt(index ((E)value) ordinal());
public Object deepCopy(Object value) throws HibernateException
return value;
public boolean isMutable()
return false;
public Object assemble(Serializable cached Object owner)
throws HibernateException
return cached;
public Serializable disassemble(Object value) throws HibernateException
return (Serializable)value;
public Object replace(Object original Object target Object owner)
throws HibernateException
return original;
public int hashCode(Object x) throws HibernateException
return x hashCode();
public boolean equals(Object x Object y) throws HibernateException
if (x == y)
return true;
if (null == x || null == y)
return false;
return x equals(y);
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