Hibernate Generate Uuid As Primary Keys
Posted : admin On 17.12.2020MySQL UUID vs. Auto-Increment INT as primary key Pros. Using UUID for a primary key brings the following advantages. UUID values are unique across tables, databases, and even servers that allow you to merge rows from different databases or distribute databases across servers. Feb 28, 2016 Auto increment keys vs. Tldr: Programmers should love values and UUID is a value. Today I would like to write about not so obvious point of view on. Hibernate to generate id (primary key) The optional child element names a Java class used to generate unique identifiers for instances of the persistent class increment generates identifiers of type long, short or int that are unique only when no.
Hibernate Uuid String
UUID / GUID (Universally / Globally Unique Identifier) is frequently use in programming. Some of its usage are for creating random file names, session id in web application, transaction id and for record’s primary keys in database replacing the sequence or auto generated number.
To generate UUID in Java we can use the java.util.UUID class. This class was introduced in JDK 1.5. The UUID.randomUUID() method return a UUID object. To obtain the value of the random string generated we need to call the UUID.toString() method.
We can also get the version and the variant of the UUID using the version() method and variant() method respectively. Let’s see the code snippet below:
The result of our program is: Create bootable usb download mac.
Hibernate Generate Uuid As Primary Keys Free
- How do I backup MySQL databases in Ubuntu? - December 16, 2019
- How do I set the time of java.util.Date instance to 00:00:00? - October 24, 2019
- How to Install Consolas Font in Mac OS X? - March 29, 2019
Postgresql Uuid As Primary Key
Hibernate Generate Uuid As Primary Keys In Florida
| importjava.io.Serializable; |
| importjava.nio.ByteBuffer; |
| importjava.util.Arrays; |
| importjava.util.UUID; |
| importjavax.persistence.Access; |
| importjavax.persistence.AccessType; |
| importjavax.persistence.Column; |
| importjavax.persistence.Embeddable; |
| @Embeddable |
| @Access(AccessType.FIELD) |
| publicclassUniqueIdimplementsSerializable { |
| privatestaticfinallong serialVersionUID =4458438725376203754L; |
| @Column(columnDefinition='BINARY(16)', length=16, updatable=false, nullable=false) |
| privatebyte[] id; |
| publicUniqueId() {} |
| publicUniqueId(byte[] id) { |
| this.id = id; |
| } |
| publicUniqueId(Stringid) { |
| this(toByteArray(UUID.fromString(id))); |
| } |
| @Override |
| publicStringtoString() { |
| return toUUID(id).toString(); |
| } |
| publicstaticUniqueIdfromString(Strings) { |
| return fromUUID(UUID.fromString(s)); |
| } |
| publicstaticUniqueIdfromUUID(UUIDuuid) { |
| returnnewUniqueId(toByteArray(uuid)); |
| } |
| privatestaticbyte[] toByteArray(UUIDuuid) { |
| ByteBuffer bb =ByteBuffer.wrap(newbyte[16]); |
| bb.putLong(uuid.getMostSignificantBits()); // order is important here! |
| bb.putLong(uuid.getLeastSignificantBits()); |
| return bb.array(); |
| } |
| privatestaticUUIDtoUUID(byte[] byteArray) { |
| long msb =0; |
| long lsb =0; |
| for (int i =0; i <8; i++) |
| msb = (msb <<8) (byteArray[i] &0xff); |
| for (int i =8; i <16; i++) |
| lsb = (lsb <<8) (byteArray[i] &0xff); |
| UUID result =newUUID(msb, lsb); |
| return result; |
| } |
| @Override |
| publicinthashCode() { |
| finalint prime =31; |
| int result =1; |
| result = prime * result +Arrays.hashCode(id); |
| return result; |
| } |
| @Override |
| publicbooleanequals(Objectobj) { |
| if (this obj) |
| returntrue; |
| if (obj null) |
| returnfalse; |
| if (getClass() != obj.getClass()) |
| returnfalse; |
| UniqueId other = (UniqueId) obj; |
| if (!Arrays.equals(id, other.id)) |
| returnfalse; |
| returntrue; |
| } |
| publicstaticUniqueIdgenerate() { |
| return fromUUID(UUID.randomUUID()); |
| } |
| } |
commented Feb 12, 2016
Generate sha512 key pair commandline. Lifesaver! Used this for general byte[] primary keys with a reordered UUID component |