1 package com.magicode.jpa.helloworld;
  2
  3 import java.util.Date;
  4
  5 import javax.persistence.Column;
  6 import javax.persistence.Entity;
  7 import javax.persistence.GeneratedValue;
  8 import javax.persistence.GenerationType;
  9 import javax.persistence.Id;
 10 import javax.persistence.Table;
 11 import javax.persistence.Temporal;
 12 import javax.persistence.TemporalType;
 13 import javax.persistence.Transient;
 14
 15 /**
 16  * @Entity 用于注明该类是一个实体类
 17  * @Table(name="t_customer") 表明该实体类映射到数据库的 t_customer 表
 18  */
 19 @Table(name="t_customer")
 20 @Entity
 21 public class Customer {
 22
 23     private Integer id;
 24     private String lastName;
 25
 26     private String email;
 27     private int age;
 28
 29     private Date birthday;
 30
 31     private Date createdTime;
 32
 33     /**
 34      * @GeneratedValue(strategy=GenerationType.AUTO) 指明主键生成策略为AUTO
 35      * @Id 表明实体类的主键
 36      */
 37     @GeneratedValue(strategy=GenerationType.AUTO)
 38     @Id
 39     public Integer getId() {
 40         return id;
 41     }
 42
 43     /**
 44      * @Column 指明lastName属性映射到表的 LAST_NAME 列中
 45      * 同时还可以指定其长度、能否为null等数据限定条件
 46      */
 47     @Column(name="LAST_NAME", length=50, nullable=false)
 48     public String getLastName() {
 49         return lastName;
 50     }
 51
 52     /**
 53      * 利用 @Temporal 来限定birthday为DATE型
 54      */
 55     @Column(name="birthday")
 56     @Temporal(TemporalType.DATE)
 57     public Date getBirthday() {
 58         return birthday;
 59     }
 60
 61     /*
 62      * 通过 @Column 的 columnDefinition 属性将CREATED_TIME列
 63      * 映射为“DATE”类型
 64      */
 65     @Column(name="CREATED_TIME", columnDefinition="DATE")
 66     public Date getCreatedTime() {
 67         return createdTime;
 68     }
 69
 70     /*
 71      * 通过 @Column 的 columnDefinition 属性将email列
 72      * 映射为“TEXT”类型
 73      */
 74     @Column(columnDefinition="TEXT")
 75     public String getEmail() {
 76         return email;
 77     }
 78
 79     /*
 80      * 工具方法，不需要映射为数据表的一列
 81      */
 82     @Transient
 83     public String getInfo(){
 84         return "lastName: " + lastName + " email: " + email;
 85     }
 86
 87     public int getAge() {
 88         return age;
 89     }
 90
 91     public void setId(Integer id) {
 92         this.id = id;
 93     }
 94
 95     public void setLastName(String lastName) {
 96         this.lastName = lastName;
 97     }
 98
 99     public void setEmail(String email) {
100         this.email = email;
101     }
102
103     public void setAge(int age) {
104         this.age = age;
105     }
106
107     public void setBirthday(Date birthday) {
108         this.birthday = birthday;
109     }
110
111     public void setCreatedTime(Date createdTime) {
112         this.createdTime = createdTime;
113     }
114
115 }

// 4、调用EntityManager的persist方法完成持久化过程
Customer customer = new Customer();
customer.setAge(9);
customer.setEmail("Tom@163.com");
customer.setLastName("Tom");
//添加1
customer.setBirthday(new Date());
//添加2
customer.setCreatedTime(new Date());
em.persist(customer);