Java/JPA/Column
Содержание
Convert Java String Type To Varchar 40
<source lang="java">
File: Professor.java
import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; @Entity public class Professor {
@Id @Column(columnDefinition="VARCHAR(40)") private String name; @Column(precision=8, scale=2) private float hourlyRate; public String getName() { return name; } public void setName(String name) { this.name = name; } public float getHourlyRate() { return hourlyRate; } public void setHourlyRate(float hourlyRate) { this.hourlyRate = hourlyRate; }
}
File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; }
public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); service.findAllProfessors(); util.checkData("select * from Professor"); em.getTransaction().rumit(); em.close(); emf.close(); }
}
File: persistence.xml
<persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
Mark Column Precision And Scale
<source lang="java">
File: Professor.java
import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; @Entity public class Professor {
@Id @Column(length=40) private String name; @Column(precision=8, scale=2) private float hourlyRate; public String getName() { return name; } public void setName(String name) { this.name = name; } public float getHourlyRate() { return hourlyRate; } public void setHourlyRate(float hourlyRate) { this.hourlyRate = hourlyRate; }
}
File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; }
public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); service.findAllProfessors(); util.checkData("select * from Professor"); em.getTransaction().rumit(); em.close(); emf.close(); }
}
File: persistence.xml
<persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
Not Updatable Column
<source lang="java">
File: Professor.java
import java.util.ArrayList; import java.util.Collection; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToMany; @Entity public class Professor {
@Id private int id; private String name; @OneToMany(mappedBy="employee") private Collection<ProjectAssignment> assignments; public Professor() { assignments = new ArrayList<ProjectAssignment>(); } 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 Collection<ProjectAssignment> getAssignments() { return assignments; } public String toString() { return "Professor id: " + getId() + " name: " + getName(); }
}
File: ProfessorService.java import java.util.Collection; import java.util.Date; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; } public Project createProject(String name, int id) { Project emp = new Project(); emp.setId(id); emp.setName(name); em.persist(emp); return emp; } public Professor createProfessor(String country, int id, String name) { Professor emp = new Professor(); emp.setId(id); emp.setName(name); em.persist(emp); return emp; } public void addProfessorProject(int id, int projId) { Professor emp = findProfessor(id); Project proj = em.find(Project.class, projId); ProjectAssignment assign = new ProjectAssignment(emp, proj); em.persist(assign); emp.getAssignments().add(assign); proj.getAssignments().add(assign); } public Professor findProfessor(int id) { return em.find(Professor.class, id); } public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); } public Collection<Project> findAllProjects() { Query query = em.createQuery("SELECT p FROM Project p"); return (Collection<Project>) query.getResultList(); }
}
File: Project.java
import java.util.ArrayList; import java.util.Collection; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.OneToMany; @Entity public class Project {
@Id private int id; private String name; @OneToMany(mappedBy="project") private Collection<ProjectAssignment> assignments; public Project() { assignments = new ArrayList<ProjectAssignment>(); } public int getId() { return id; } public void setId(int projectNo) { this.id = projectNo; } public String getName() { return name; } public void setName(String projectName) { this.name = projectName; } public Collection<ProjectAssignment> getAssignments() { return assignments; } public String toString() { return getClass().getName().substring(getClass().getName().lastIndexOf(".")+1) + " no: " + getId() + ", name: " + getName(); }
}
File: ProjectAssignment.java
import java.util.Date; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.IdClass; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.Table; import javax.persistence.Temporal; import javax.persistence.TemporalType; @Entity @Table(name = "EMP_PROJECT") @IdClass(ProjectAssignmentId.class) public class ProjectAssignment {
@Id @Column(name = "EMP_ID", insertable = false, updatable = false) private int empId; @Id @Column(name = "PROJECT_ID", insertable = false, updatable = false) private int projectId; @ManyToOne @JoinColumn(name = "EMP_ID") Professor employee; @ManyToOne @JoinColumn(name = "PROJECT_ID") Project project;
public ProjectAssignment() { } public ProjectAssignment(Professor emp, Project proj) { this.empId = emp.getId(); this.employee = emp; this.projectId = proj.getId(); this.project = proj; } public int getEmpId() { return empId; } public Professor getProfessor() { return employee; } public int getProjectId() { return projectId; } public Project getProject() { return project; }
}
File: ProjectAssignmentId.java
import java.io.Serializable; public class ProjectAssignmentId implements Serializable {
private int empId; private int projectId; public ProjectAssignmentId() {} public ProjectAssignmentId(int empId, int projectId) { this.empId = empId; this.projectId = projectId; } public int getEmpId() { return empId; } public int getProjectId() { return projectId; } public boolean equals(Object o) { return ((o instanceof ProjectAssignmentId) && empId == ((ProjectAssignmentId)o).getEmpId() && projectId == ((ProjectAssignmentId) o).getProjectId()); } public int hashCode() { return empId + projectId; }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); service.createProject("proj", 1); service.createProfessor("country", 1, "name"); service.addProfessorProject(1, 1); System.out.println("Professors:"); for (Professor emp : service.findAllProfessors()) { System.out.print(emp + " with " + emp.getAssignments().size() + " assignments"); } System.out.println("Projects:"); for (Project p : service.findAllProjects()) { System.out.print(p + " with " + p.getAssignments().size() + " assignments"); } util.checkData("select * from Project"); em.getTransaction().rumit(); em.close(); emf.close(); }
}
File: persistence.xml <persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
Nullable Column
<source lang="java">
File: Professor.java import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; @Entity public class Professor {
@Id private int id; @Column(unique=true, nullable=false) private String name; private long salary; 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 long getSalary() { return salary; } public void setSalary(long salary) { this.salary = salary; } public String toString() { return "Professor id: " + getId() + " name: " + getName(); }
}
File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; }
public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); service.findAllProfessors(); util.checkData("select * from Professor"); em.getTransaction().rumit(); em.close(); emf.close(); }
}
File: persistence.xml <persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
Set Column Definition
<source lang="java">
File: Professor.java import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; @Entity public class Professor {
@Id @Column(columnDefinition = "VARCHAR(40)") private String name; @Column(name = "START_DATE", columnDefinition = "DATE DEFAULT CURRENT_DATE") private java.sql.Date startDate; public String getName() { return name; } public void setName(String name) { this.name = name; } public java.sql.Date getStartDate() { return startDate; } public void setStartDate(java.sql.Date startDate) { this.startDate = startDate; }
}
File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; }
public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); service.findAllProfessors(); util.checkData("select * from Professor"); em.getTransaction().rumit(); em.close(); emf.close(); }
}
File: persistence.xml <persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
Set Column Definition For Many To One Mapping
<source lang="java">
File: Professor.java
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
@Entity
public class Professor {
@Id @Column(columnDefinition = "VARCHAR(40)") private String name; @ManyToOne @JoinColumn(name="MGR", columnDefinition="VARCHAR(40)") private Professor manager; public String getName() { return name; } public void setName(String name) { this.name = name; } public Professor getManager() { return manager; } public void setManager(Professor manager) { this.manager = manager; }
}
File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; }
public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); service.findAllProfessors(); util.checkData("select * from Professor"); em.getTransaction().rumit(); em.close(); emf.close(); }
}
File: persistence.xml
<persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
Set Column Length
<source lang="java">
File: Professor.java
import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; @Entity public class Professor {
@Id @Column(length=40) private String name; @ManyToOne @JoinColumn(name="MGR") private Professor manager; public String getName() { return name; } public void setName(String name) { this.name = name; } public Professor getManager() { return manager; } public void setManager(Professor manager) { this.manager = manager; }
}
File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; }
public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); service.findAllProfessors(); util.checkData("select * from Professor"); em.getTransaction().rumit(); em.close(); emf.close(); }
}
File: persistence.xml
<persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>
Set Column Name
<source lang="java">
File: Professor.java
import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.Table; @Entity //@Table(name="EMP", schema="HR") @Table(name="EMP") public class Professor {
@Id @Column(name = "EMP_ID") private int id; @Column(name = "COMM") private String name; @Column(name = "SAL") private long salary; public Professor() { } public Professor(int id) { this.id = id; } 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 long getSalary() { return salary; } public void setSalary(long salary) { this.salary = salary; } public String toString() { return "Professor id: " + getId() + " name: " + getName() + " salary: " + getSalary(); }
}
File: ProfessorService.java import java.util.Collection; import javax.persistence.EntityManager; import javax.persistence.Query; public class ProfessorService {
protected EntityManager em; public ProfessorService(EntityManager em) { this.em = em; } public Professor createProfessor(int id, String name, long salary) { Professor emp = new Professor(id); emp.setName(name); emp.setSalary(salary); em.persist(emp); return emp; } public void removeProfessor(int id) { Professor emp = findProfessor(id); if (emp != null) { em.remove(emp); } } public Professor raiseProfessorSalary(int id, long raise) { Professor emp = em.find(Professor.class, id); if (emp != null) { emp.setSalary(emp.getSalary() + raise); } return emp; } public Professor findProfessor(int id) { return em.find(Professor.class, id); } public Collection<Professor> findAllProfessors() { Query query = em.createQuery("SELECT e FROM Professor e"); return (Collection<Professor>) query.getResultList(); }
}
File: JPAUtil.java import java.io.Reader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class JPAUtil {
Statement st; public JPAUtil() throws Exception{ Class.forName("org.hsqldb.jdbcDriver"); System.out.println("Driver Loaded."); String url = "jdbc:hsqldb:data/tutorial"; Connection conn = DriverManager.getConnection(url, "sa", ""); System.out.println("Got Connection."); st = conn.createStatement(); } public void executeSQLCommand(String sql) throws Exception { st.executeUpdate(sql); } public void checkData(String sql) throws Exception { ResultSet rs = st.executeQuery(sql); ResultSetMetaData metadata = rs.getMetaData(); for (int i = 0; i < metadata.getColumnCount(); i++) { System.out.print("\t"+ metadata.getColumnLabel(i + 1)); } System.out.println("\n----------------------------------"); while (rs.next()) { for (int i = 0; i < metadata.getColumnCount(); i++) { Object value = rs.getObject(i + 1); if (value == null) { System.out.print("\t "); } else { System.out.print("\t"+value.toString().trim()); } } System.out.println(""); } }
}
File: Main.java import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence; public class Main {
public static void main(String[] a) throws Exception { JPAUtil util = new JPAUtil(); EntityManagerFactory emf = Persistence.createEntityManagerFactory("ProfessorService"); EntityManager em = emf.createEntityManager(); ProfessorService service = new ProfessorService(em); em.getTransaction().begin(); Professor emp = service.createProfessor(158, "AAA", 45000); em.getTransaction().rumit(); System.out.println("Persisted " + emp); util.checkData("select * from EMP"); // remove an employee em.getTransaction().begin(); service.removeProfessor(158); em.getTransaction().rumit(); System.out.println("Removed Professor 158"); util.checkData("select * from EMP"); em.close(); emf.close(); }
}
File: persistence.xml <persistence xmlns="http://java.sun.ru/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.ru/xml/ns/persistence http://java.sun.ru/xml/ns/persistence/persistence" version="1.0"> <persistence-unit name="JPAService" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/> <property name="hibernate.hbm2ddl.auto" value="update"/> <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver"/> <property name="hibernate.connection.username" value="sa"/> <property name="hibernate.connection.password" value=""/> <property name="hibernate.connection.url" value="jdbc:hsqldb:data/tutorial"/> </properties> </persistence-unit>
</persistence>
</source>