JPA 日期列定义示例

时间类型是可以在持久状态映射中使用的基于时间的类型集合。

支持的时间类型的列表包括三个java.sql类型，java.sql.Date java.sql.Time和java.sql.Timestamp，以及两个java.util类型，java.util.Date和java.util.Calendar。

在JPA中，我们可以创建数据类型列并设置其默认值。

@Column(name = "START_DATE", columnDefinition = "DATE DEFAULT CURRENT_DATE") private java.sql.Date startDate; 

例子

下面的代码来自Person.java。

package cn.w3cschool.common; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.Table; @Entity @Table(name="EMP") public class Person { @Id @Column(name = "EMP_ID") private long id; @Column(length=40) private String name; private String surname; @Column(name = "START_DATE", columnDefinition = "DATE DEFAULT CURRENT_DATE") private java.sql.Date startDate; public Person() {} public Person(String name, String surname) { this.name = name; this.surname = surname; } public java.sql.Date getStartDate() { return startDate; } public void setStartDate(java.sql.Date startDate) { this.startDate = startDate; } 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 getSurname() { return surname; } public void setSurname(String surname) { this.surname = surname; } @Override public String toString() { return "Person [id=" + id + ", name=" + name + ", surname=" + surname + ", startDate=" + startDate + "]"; } } 

下面的代码来自PersonDaoImpl.java。

package cn.w3cschool.common; import java.sql.Date; 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", "Smith"); p1.setId(1L); p1.setStartDate(new Date(System.currentTimeMillis())); Person p2 = new Person("Jack", "Kook"); p2.setId(2L); p2.setStartDate(new Date(System.currentTimeMillis())); 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 Date_Column_Definition.zip

上面的代码生成以下结果。

以下是数据库表转储。

Table Name: EMP Row: Column Name: EMP_ID, Column Type: BIGINT: Column Value: 1 Column Name: NAME, Column Type: VARCHAR: Column Value: Tom Column Name: START_DATE, Column Type: DATE: Column Value: 2014-12-29 Column Name: SURNAME, Column Type: VARCHAR: Column Value: Smith Row: Column Name: EMP_ID, Column Type: BIGINT: Column Value: 2 Column Name: NAME, Column Type: VARCHAR: Column Value: Jack Column Name: START_DATE, Column Type: DATE: Column Value: 2014-12-29 Column Name: SURNAME, Column Type: VARCHAR: Column Value: Kook