Java Tutorial/JPA/Generated ID
Содержание
- 1 Create Table From Table Generator
- 2 Create Your Own Table For Table Generator
- 3 Generated Value Based On Sequence Generator
- 4 Generate ID From a Table
- 5 ID Generation Type: AUTO
- 6 ID Generation Type: IDENTITY
- 7 ID Generation Type: SEQUENCE
- 8 ID Generation Type: TABLE
- 9 JPA Create Sequence Table For You
- 10 Sequence Generator Name Init Value And Size
- 11 Use Sequence Generator
Create Table From Table Generator
File: Student.java
<source lang="java">
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.TableGenerator; @Entity public class Student {
@TableGenerator(name = "Address_Gen", table = "ID_GEN", pkColumnName = "GEN_NAME", valueColumnName = "GEN_VAL", pkColumnValue = "Addr_Gen", initialValue = 10000, allocationSize = 100) @Id @GeneratedValue(strategy = GenerationType.TABLE, generator = "Address_Gen") private int id; transient private String name; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String toString() { return "\n\nID:" + id + "\nName:" + name + "\n\n"; }
}</source>
Create Your Own Table For Table Generator
File: Student.java
<source lang="java">
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.TableGenerator; @Entity public class Student {
@Id @TableGenerator(name = "EmpPkGen", table = "ID_GEN", pkColumnName = "GEN_NAME", pkColumnValue = "Emp_Gen", valueColumnName = "GEN_VAL", initialValue = 0, allocationSize = 100 ) @GeneratedValue(strategy=GenerationType.TABLE)
/*create table id_gen (
gen_name varchar(80), gen_val integer, constraint pk_id_gen primary key (gen_name)
);
- /
private int id; transient private String name;
public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; }
public String toString() { return "\n\nID:" + id + "\nName:" + name + "\n\n"; }
}</source>
Generated Value Based On Sequence Generator
File: Student.java
<source lang="java">
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.SequenceGenerator; @Entity public class Student {
@SequenceGenerator(name="Emp_Gen", sequenceName="Emp_Seq") @Id @GeneratedValue(generator="Emp_Gen") private int id; private String name;
public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; }
public String toString() { return "\n\nID:" + id + "\nName:" + name + "\n\n"; }
}</source>
Generate ID From a Table
File: Student.java
<source lang="java">
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.TableGenerator; @Entity public class Student {
@TableGenerator(name = "Address_Gen", table = "ID_GEN", pkColumnName = "GEN_NAME", valueColumnName = "GEN_VAL", pkColumnValue = "Addr_Gen", initialValue = 10000, allocationSize = 100) @Id @GeneratedValue(strategy = GenerationType.TABLE, generator = "Address_Gen") private int id; transient private String name; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String toString() { return "\n\nID:" + id + "\nName:" + name + "\n\n"; }
}</source>
ID Generation Type: AUTO
File: Helper.java
<source lang="java">
import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class Helper {
public static void checkData() throws Exception { Class.forName("org.hsqldb.jdbcDriver"); Connection conn = DriverManager.getConnection("jdbc:hsqldb:data/tutorial", "sa", ""); Statement st = conn.createStatement(); ResultSet mrs = conn.getMetaData().getTables(null, null, null, new String[] { "TABLE" }); while (mrs.next()) { String tableName = mrs.getString(3); System.out.println("\n\n\n\nTable Name: "+ tableName); ResultSet rs = st.executeQuery("select * from " + tableName); ResultSetMetaData metadata = rs.getMetaData(); while (rs.next()) { System.out.println(" Row:"); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.println(" Column Name: "+ metadata.getColumnLabel(i + 1)+ ", "); System.out.println(" Column Type: "+ metadata.getColumnTypeName(i + 1)+ ": "); Object value = rs.getObject(i + 1); System.out.println(" Column Value: "+value+"\n"); } } } }
}</source>
ID Generation Type: IDENTITY
File: Main.java
<source lang="java">
import java.sql.Timestamp; import java.util.List; import java.util.UUID; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; import javax.persistence.Query; public class Main {
static EntityManagerFactory emf = Persistence.createEntityManagerFactory("JPAService"); static EntityManager em = emf.createEntityManager(); public static void main(String[] a) throws Exception { em.getTransaction().begin(); Student student = new Student(); student.setName("Joe"); em.persist(student); em.flush(); em.getTransaction().rumit(); Query query = em.createQuery("SELECT e FROM Student e"); List<Student> list = (List<Student>) query.getResultList(); System.out.println(list); em.close(); emf.close(); Helper.checkData(); }
}</source>
ID Generation Type: SEQUENCE
File: Main.java
<source lang="java">
import java.sql.Timestamp; import java.util.List; import java.util.UUID; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; import javax.persistence.Query; public class Main {
static EntityManagerFactory emf = Persistence.createEntityManagerFactory("JPAService"); static EntityManager em = emf.createEntityManager(); public static void main(String[] a) throws Exception { em.getTransaction().begin(); Student student = new Student(); student.setName("Joe"); em.persist(student); em.flush(); em.getTransaction().rumit(); Query query = em.createQuery("SELECT e FROM Student e"); List<Student> list = (List<Student>) query.getResultList(); System.out.println(list); em.close(); emf.close(); Helper.checkData(); }
}</source>
ID Generation Type: TABLE
File: Helper.java
<source lang="java">
import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class Helper {
public static void checkData() throws Exception { Class.forName("org.hsqldb.jdbcDriver"); Connection conn = DriverManager.getConnection("jdbc:hsqldb:data/tutorial", "sa", ""); Statement st = conn.createStatement(); ResultSet mrs = conn.getMetaData().getTables(null, null, null, new String[] { "TABLE" }); while (mrs.next()) { String tableName = mrs.getString(3); System.out.println("\n\n\n\nTable Name: "+ tableName); ResultSet rs = st.executeQuery("select * from " + tableName); ResultSetMetaData metadata = rs.getMetaData(); while (rs.next()) { System.out.println(" Row:"); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.println(" Column Name: "+ metadata.getColumnLabel(i + 1)+ ", "); System.out.println(" Column Type: "+ metadata.getColumnTypeName(i + 1)+ ": "); Object value = rs.getObject(i + 1); System.out.println(" Column Value: "+value+"\n"); } } } }
}</source>
JPA Create Sequence Table For You
File: Helper.java
<source lang="java">
import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class Helper {
public static void checkData() throws Exception { Class.forName("org.hsqldb.jdbcDriver"); Connection conn = DriverManager.getConnection("jdbc:hsqldb:data/tutorial", "sa", ""); Statement st = conn.createStatement(); ResultSet mrs = conn.getMetaData().getTables(null, null, null, new String[] { "TABLE" }); while (mrs.next()) { String tableName = mrs.getString(3); System.out.println("\n\n\n\nTable Name: "+ tableName); ResultSet rs = st.executeQuery("select * from " + tableName); ResultSetMetaData metadata = rs.getMetaData(); while (rs.next()) { System.out.println(" Row:"); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.println(" Column Name: "+ metadata.getColumnLabel(i + 1)+ ", "); System.out.println(" Column Type: "+ metadata.getColumnTypeName(i + 1)+ ": "); Object value = rs.getObject(i + 1); System.out.println(" Column Value: "+value+"\n"); } } } }
}</source>
Sequence Generator Name Init Value And Size
File: Customer.java
<source lang="java">
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.PostLoad; import javax.persistence.PostPersist; import javax.persistence.PostRemove; import javax.persistence.PostUpdate; import javax.persistence.PrePersist; import javax.persistence.PreRemove; import javax.persistence.PreUpdate; import javax.persistence.SequenceGenerator; @Entity @SequenceGenerator(name = "SequenceIdGenerator",
sequenceName = "SEQ_ID_GEN", initialValue = 100, allocationSize = 20)
public class Customer implements java.io.Serializable {
@Id @GeneratedValue(generator = "SequenceIdGenerator") private int id; private String lastName; private String firstName;
public int getId() { return id; } public void setId(int pk) { id = pk; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } @PrePersist public void prePersist() { System.out.println("@PrePersist"); } @PostPersist public void postPersist() { System.out.println("@PostPersist"); } @PostLoad public void postLoad() { System.out.println("@PostLoad"); } @PreUpdate public void preUpdate() { System.out.println("@PreUpdate"); } @PostUpdate public void postUpdate() { System.out.println("@PostUpdate"); } @PreRemove public void preRemove() { System.out.println("@PreRemove"); } @PostRemove public void postRemove() { System.out.println("@PostRemove"); }
}</source>
Use Sequence Generator
File: Student.java
<source lang="java">
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.SequenceGenerator; @Entity public class Student {
@SequenceGenerator(name="Emp_Gen", sequenceName="Emp_Seq") @Id @GeneratedValue(generator="Emp_Gen") private int id; private String name;
public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; }
public String toString() { return "\n\nID:" + id + "\nName:" + name + "\n\n"; }
}</source>