File: Employee.java
import java.io.Serializable; import java.util.ArrayList; import java.util.Collection; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.EntityResult; import javax.persistence.FieldResult; import javax.persistence.Id; import javax.persistence.IdClass; import javax.persistence.JoinColumn; import javax.persistence.JoinColumns; import javax.persistence.ManyToOne; import javax.persistence.OneToMany; import javax.persistence.SqlResultSetMapping; import javax.persistence.Table; @Entity @Table(name="EMP") @IdClass(EmployeeId.class) @SqlResultSetMapping( name="EmployeeAndManager", entities={ @EntityResult(entityClass=Employee.class), @EntityResult( entityClass=Employee.class, fields={ @FieldResult(name="country", column="MGR_COUNTRY"), @FieldResult(name="id", column="MGR_ID"), @FieldResult(name="name", column="MGR_NAME"), @FieldResult(name="manager.country", column="MGR_MGR_COUNTRY"), @FieldResult(name="manager.id", column="MGR_MGR_ID") } ) } ) public class Employee { @Id private String country; @Id private int id; private String name; @ManyToOne @JoinColumns({ @JoinColumn(name="MANAGER_COUNTRY", referencedColumnName="COUNTRY"), @JoinColumn(name="MANAGER_ID", referencedColumnName="ID") }) private Employee manager; @OneToMany(mappedBy="manager") private Collection<Employee> directs = new ArrayList<Employee>(); public int getId() { return id; } public void setId(int id) { this.id = id; } public String getCountry() { return country; } public void setCountry(String country) { this.country = country; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Collection<Employee> getDirects() { return directs; } public Employee getManager() { return manager; } public void setManager(Employee manager) { this.manager = manager; } } class EmployeeId implements Serializable { private String country; private int id; public EmployeeId() {} public EmployeeId(String country, int id) { this.country = country; this.id = id; } public String getCountry() { return country; } public int getId() { return id; } public boolean equals(Object o) { return ((o instanceof EmployeeId) && country.equals(((EmployeeId)o).getCountry()) && id == ((EmployeeId) o).getId()); } public int hashCode() { return country.hashCode() + id; } }
File: Helper.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"); } } } } }
File: Main.java
import java.util.List; 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(); Query query = em.createNativeQuery( "SELECT e.country, e.id, e.name, " + "e.manager_country, e.manager_id, m.country AS mgr_country, " + "m.id AS mgr_id, m.name AS mgr_name," + "m.manager_country AS mgr_mgr_country, m.manager_id AS mgr_mgr_id " + "FROM emp e, emp m ", "EmployeeAndManager"); List list = query.getResultList(); em.getTransaction().commit(); em.close(); emf.close(); Helper.checkData(); } }
File: persistence.xml
<persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/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>Download: JPA-SqlResultSetMappingWithEntityResultAndFieldResult.zip( 5,291 k)
22.30.ResultSet Mapping | ||||
22.30.1. | Single Table ResultSet Mapping | |||
22.30.2. | Sql ResultSet Mapping With Entity Result And Field Result | |||
22.30.3. | Sql ResultSet Mapping For Hierarchical Entity | |||
22.30.4. | Sql ResultSet Mapping With Entity And Column | |||
22.30.5. | Resultset Mapping With Two Entities | |||
22.30.6. | ID Class ResultSet Mapping | |||
22.30.7. | Alias Column In Resultset Mapping |