hibernate id 生成策略 annotation @GeneratedValue

方法很简单，只需要在id属性上添加@GeneratedValue的注释即可，如下：

@Entity

public class Teacher {

 //private TeacherPK pk;

 private int id;

 private String name;

 

 @Id

 @GeneratedValue//////////默认使用的是AUTO类型，还有TABLE,IDENTITY(使用于sql server,mysql数据库中,oracle不适用),SEQUENCE类型(oracle使用该种)，通过@GeneratedValue(strategy=GenerationType.IDENTITY)配置

 public int getId() {

  return id;

 }

 }

－－－－－－－

当使用SEQUENCES的时候可以使用自定义的SEQUENCES生成器的名字，只需要在类名上加上注释：@SequenceGenerator(name="teacherSEQ", sequenceName="teacherSEQ_DB")

import java.util.Date;

import javax.persistence.EmbeddedId;

import javax.persistence.Entity;

import javax.persistence.EnumType;

import javax.persistence.Enumerated;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.IdClass;

import javax.persistence.SequenceGenerator;

import javax.persistence.Id;

import javax.persistence.Temporal;

import javax.persistence.TemporalType;

import javax.persistence.Transient;

@Entity

@SequenceGenerator(name="teacherSEQ", sequenceName="teacherSEQ_DB")

public class Teacher {

 //private TeacherPK pk;

 private int id;

 private String name;

 private String title;

 private String yourWifeName;

 private Date birthDate;

 private boolean good;

 private Gender gender;

 

 @Enumerated(EnumType.STRING)

 public Gender getGender() {

  return gender;

 }

 public void setGender(Gender gender) {

  this.gender = gender;

 }

 public boolean isGood() {

  return good;

 }

 public void setGood(boolean good) {

  this.good = good;

 }

 @Transient

 public String getYourWifeName() {

  return yourWifeName;

 }

 public void setYourWifeName(String yourWifeName) {

  this.yourWifeName = yourWifeName;

 }

 @Id

 @GeneratedValue(strategy=GenerationType.TABLE, generator="Teacher_GEN")////使用TableGenerator自动生成id的方式

//////还可以写成 @GeneratedValue（strategy=GenerationType.SEQUENCE, generator="teacherSEQ"）

 public int getId() {

  return id;

 }

 public void setId(int id) {

  this.id = id;

 }

 

 @Id

 public String getName() {

  return name;

 }

 public void setName(String name) {

  this.name = name;

 }

 public String getTitle() {

  return title;

 }

 public void setTitle(String title) {

  this.title = title;

 }

 @Temporal(TemporalType.TIME)

 public Date getBirthDate() {

  return birthDate;

 }

 public void setBirthDate(Date birthDate) {

  this.birthDate = birthDate;

 } 

}