JPA教程：映射实体–第1部分

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import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class Address {
  @Id
  private Integer id;

  private String street;
  private String city;
  private String province;
  private String country;
  private String postcode;

  /**
   * @return the id
   */
  public Integer getId() {
    return id;
  }

  /**
   * @param id the id to set
   */
  public Address setId(Integer id) {
    this.id = id;
    return this;
  }

  /**
   * @return the street
   */
  public String getStreet() {
    return street;
  }

  /**
   * @param street the street to set
   */
  public Address setStreet(String street) {
    this.street = street;
    return this;
  }

  /**
   * @return the city
   */
  public String getCity() {
    return city;
  }

  /**
   * @param city the city to set
   */
  public Address setCity(String city) {
    this.city = city;
    return this;
  }

  /**
   * @return the province
   */
  public String getProvince() {
    return province;
  }

  /**
   * @param province the province to set
   */
  public Address setProvince(String province) {
    this.province = province;
    return this;
  }

  /**
   * @return the country
   */
  public String getCountry() {
    return country;
  }

  /**
   * @param country the country to set
   */
  public Address setCountry(String country) {
    this.country = country;
    return this;
  }

  /**
   * @return the postcode
   */
  public String getPostcode() {
    return postcode;
  }

  /**
   * @param postcode the postcode to set
   */
  public Address setPostcode(String postcode) {
    this.postcode = postcode;
    return this;
  }
}

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import com.keertimaan.javasamples.jpaexample.entity.Address;
import javax.persistence.EntityManager;
import com.keertimaan.javasamples.jpaexample.persistenceutil.PersistenceManager;

public class Main {
  public static void main(String[] args) {
    EntityManager em = PersistenceManager.INSTANCE.getEntityManager();

    Address address = new Address().setId(1)
        .setCity("Dhaka")
        .setCountry("Bangladesh")
        .setPostcode("1000")
        .setStreet("Poribagh");
    em.getTransaction()
        .begin();
    em.persist(address);
    em.getTransaction()
        .commit();
    System.out.println("addess is saved! It has id: " + address.getId());

    Address anotherAddress = new Address().setId(2)
        .setCity("Shinagawa-ku, Tokyo")
        .setCountry("Japan")
        .setPostcode("140-0002")
        .setStreet("Shinagawa Seaside Area");
    em.getTransaction()
        .begin();
    em.persist(anotherAddress);
    em.getTransaction()
        .commit();
    em.close();
    System.out.println("anotherAddress is saved! It has id: " + anotherAddress.getId());

    PersistenceManager.INSTANCE.close();
  }
}

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import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.GeneratedValue;

@Entity
public class Address {
  @Id
  @GeneratedValue
  private Integer id;

  // Rest of the class code........

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Address anotherAddress = new Address()
    .setCity("Shinagawa-ku, Tokyo")
    .setCountry("Japan")
    .setPostcode("140-0002")
    .setStreet("Shinagawa Seaside Area");
em.getTransaction()
    .begin();
em.persist(anotherAddress);
em.getTransaction()
    .commit();