如何在JPA和Hibernate中使用Java 8 LocalDateTime [英] How to use the Java 8 LocalDateTime with JPA and Hibernate
问题描述
我有以下类别描述代码段:
I have the following class description snippet:
...
@Column(name = "invalidate_token_date")
@Temporal(TemporalType.TIMESTAMP)
private LocalDateTime invalidateTokenDate;
....
此代码在Hibernate 4上不起作用,因为@Temporal
不支持LocalDateTime.
This code doesn't work on Hibernate 4 because @Temporal
doesn't support LocalDateTime.
我从 Joda-Time 看到了有关如何使用 LocalDateTime 的建议,但我使用的是Java 8.
I saw the suggestion on how to use LocalDateTime from Joda-Time but I use Java 8.
推荐答案
Since Hibernate 4 doesn't support it you need to implement a user type as shown in this example.
import org.hibernate.HibernateException;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.type.StandardBasicTypes;
import org.hibernate.usertype.EnhancedUserType;
import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.Date;
public class LocalDateTimeUserType implements EnhancedUserType, Serializable {
private static final int[] SQL_TYPES = new int[]{Types.TIMESTAMP};
@Override
public int[] sqlTypes() {
return SQL_TYPES;
}
@Override
public Class returnedClass() {
return LocalDateTime.class;
}
@Override
public boolean equals(Object x, Object y) throws HibernateException {
if (x == y) {
return true;
}
if (x == null || y == null) {
return false;
}
LocalDateTime dtx = (LocalDateTime) x;
LocalDateTime dty = (LocalDateTime) y;
return dtx.equals(dty);
}
@Override
public int hashCode(Object object) throws HibernateException {
return object.hashCode();
}
@Override
public Object nullSafeGet(ResultSet resultSet, String[] names, SessionImplementor session, Object owner)
throws HibernateException, SQLException {
Object timestamp = StandardBasicTypes.TIMESTAMP.nullSafeGet(resultSet, names, session, owner);
if (timestamp == null) {
return null;
}
Date ts = (Date) timestamp;
Instant instant = Instant.ofEpochMilli(ts.getTime());
return LocalDateTime.ofInstant(instant, ZoneId.systemDefault());
}
@Override
public void nullSafeSet(PreparedStatement preparedStatement, Object value, int index, SessionImplementor session)
throws HibernateException, SQLException {
if (value == null) {
StandardBasicTypes.TIMESTAMP.nullSafeSet(preparedStatement, null, index, session);
} else {
LocalDateTime ldt = ((LocalDateTime) value);
Instant instant = ldt.atZone(ZoneId.systemDefault()).toInstant();
Date timestamp = Date.from(instant);
StandardBasicTypes.TIMESTAMP.nullSafeSet(preparedStatement, timestamp, index, session);
}
}
@Override
public Object deepCopy(Object value) throws HibernateException {
return value;
}
@Override
public boolean isMutable() {
return false;
}
@Override
public Serializable disassemble(Object value) throws HibernateException {
return (Serializable) value;
}
@Override
public Object assemble(Serializable cached, Object value) throws HibernateException {
return cached;
}
@Override
public Object replace(Object original, Object target, Object owner) throws HibernateException {
return original;
}
@Override
public String objectToSQLString(Object object) {
throw new UnsupportedOperationException();
}
@Override
public String toXMLString(Object object) {
return object.toString();
}
@Override
public Object fromXMLString(String string) {
return LocalDateTime.parse(string);
}
}
然后可以在带有@Type批注的映射中使用新的用户类型.例如
The new usertype can then be used in the mapping with the @Type annotation. For e.g.
@Type(type="com.hibernate.samples.type.LocalDateTimeUserType")
@Column(name = "invalidate_token_date")
private LocalDateTime invalidateTokenDate;
@Type批注需要一个实现userType接口的类的完整路径;这是产生映射列的目标类型的工厂.
The @Type annotation needs a full path to the class that implements the userType interface; this is the factory for producing the target type of the mapped column.
此处如何在JPA2.1中执行相同的操作
Here's how to do the same thing in JPA2.1
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