JPA 日历映射到日期示例

JPA教程 – JPA日历映射到日期示例

以下部分显示如何将java.util.Calendar映射到数据库日期类型。

@Temporal(TemporalType.DATE)
private java.util.Calendar dob;

例子

下面的代码来自Person.java。

package cn.w3cschool.common;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;

@Entity
public class Person {
    @Id
    private long id;

    private String name;

  @Temporal(TemporalType.DATE)
  private java.util.Calendar dob;

  public Person() {}

  public Person(String name) {
     this.name = name;
  }

  public java.util.Calendar getDob() {
    return dob;
  }

  public void setDob(java.util.Calendar dob) {
    this.dob = dob;
  }

  public Long getId() {
        return id;
    }
    public void setId(Long 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"+"Dob"+dob;
  }
}

下面的代码来自PersonDaoImpl.java。

package cn.w3cschool.common;

import java.util.Calendar;
import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import org.springframework.transaction.annotation.Transactional;

@Transactional
public class PersonDaoImpl {
  public void test(){
    Person p1 = new Person("Tom");
    p1.setId(1L);
    p1.setDob(Calendar.getInstance());

    Person p2 = new Person("Jack");
    p2.setId(2L);

    save(p1);
    save(p2);

    listAll();

  }
  private void listAll(){
    List<Person> persons = getAll();
    for (Person person : persons) {
      System.out.println(person);
    }

  }
    @PersistenceContext
    private EntityManager em;

    public Long save(Person person) {
        em.persist(person);
        return person.getId();
    }

    public List<Person>getAll() {
        return em.createQuery("SELECT p FROM Person p", Person.class).getResultList();
    }

}

以下代码来自App.java。

package cn.w3cschool.common;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class App {

  public static void main(String[] args) {
    ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(
        "applicationContext.xml");
    PersonDaoImpl dao = (PersonDaoImpl) context.getBean("personDao");

    dao.test();

    context.close();

    Helper.checkData();
  }
}

下载 Map_Calendar_to_Date.zip

以下是数据库表转储。

Table Name: PERSON
 Row:
    Column Name: ID,
    Column Type: BIGINT:
    Column Value: 1

    Column Name: DOB,
    Column Type: DATE:
    Column Value: 2014-12-29

    Column Name: NAME,
    Column Type: VARCHAR:
    Column Value: Tom

 Row:
    Column Name: ID,
    Column Type: BIGINT:
    Column Value: 2

    Column Name: DOB,
    Column Type: DATE:
    Column Value: null

    Column Name: NAME,
    Column Type: VARCHAR:
    Column Value: Jack