JPACompositePK聯合主鍵的操作

package cn.itcast.bean;
import javax.persistence.Column;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;

@Entity 
public class AirLine {
  private AirLinePK id;
  private String name;
 
public AirLine(){} 
 
public AirLine(AirLinePK id) {
 super();
 this.id = id;
}
public AirLine(String startCity,String endCity,String name){
 this.id=new AirLinePK(startCity,endCity);
 this.name=name;
}

@EmbeddedId
public AirLinePK getId() {
 return id;
}
public void setId(AirLinePK id) {
 this.id = id;
}

@Column(length=20)
public String getName() {
 return name;
}
public void setName(String name) {
 this.name = name;
} 
}
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package cn.itcast.bean;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Embeddable;

/**
 *
 * @Embeddable只使用這個實體內的屬性
 *
 */
@Embeddable
public class AirLinePK implements Serializable {

 private String startCity;
 private String endCity;
 
 public AirLinePK(){}
 
 public AirLinePK(String startCity, String endCity) {
  super();
  this.startCity = startCity;
  this.endCity = endCity;
 }
 @Column(length=3) 
 public String getStartCity() {
  return startCity;
 }
 public void setStartCity(String startCity) {
  this.startCity = startCity;
 }
 @Column(length=3)
 public String getEndCity() {
  return endCity;
 }
 public void setEndCity(String endCity) {
  this.endCity = endCity;
 }
 @Override
 public int hashCode() {
  final int prime = 31;
  int result = 1;
  result = prime * result + ((endCity == null) ? 0 : endCity.hashCode());
  result = prime * result
    + ((startCity == null) ? 0 : startCity.hashCode());
  return result;
 }
 @Override
 public boolean equals(Object obj) {
  if (this == obj)
   return true;
  if (obj == null)
   return false;
  if (getClass() != obj.getClass())
   return false;
  final AirLinePK other = (AirLinePK) obj;
  if (endCity == null) {
   if (other.endCity != null)
    return false;
  } else if (!endCity.equals(other.endCity))
   return false;
  if (startCity == null) {
   if (other.startCity != null)
    return false;
  } else if (!startCity.equals(other.startCity))
   return false;
  return true;
 }  
}
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junit測試

package junit.test;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import org.junit.BeforeClass;
import org.junit.Test;
import cn.itcast.bean.AirLine;

public class AirLineTest {
 @BeforeClass
 public static void setUpBeforeClass() throws Exception {
 }

 @Test public void save()
 {
  EntityManagerFactory factory=Persistence.createEntityManagerFactory("itcast");
     EntityManager em=factory.createEntityManager();
     em.getTransaction().begin();
     em.persist(new AirLine("PEK","SHA","北京飛上海"));
     em.getTransaction().commit();
     em.close();
     factory.close();
 }
}