属性级别注解
添加方式：
写在属性字段上面
写在属性的get访问器的上面
@Id
必须，定义了映射到数据库表的主键的属性，一个实体类可以有一个或者多个属性被映射为主键，可置于主键属性或者getXxx()前，注意：如果有多个属性定义为主键属性，该实体类必须实现serializable接口
@SequenceGenerator
@GeneratedValue
@GeneratedValue(strategy=GenerationType,generator=""):可选，用于定义主键生成策略
strategy表示主键生成策略，取值有：
GenerationType.AUTO:根据底层数据库自动选择（默认）
GenerationType.INDENTITY:根据数据库的Identity字段生成
GenerationType.SEQUENCE:使用Sequence来决定主键的取值
GenerationType.TABLE:使用指定表来决定主键取值，结合@TableGenerator使用
@Column
@Column-可将属性映射到列，使用该注解来覆盖默认值，@Column描述了数据库表中该字段的详细定义，这对于根据JPA
注解生成数据库表结构的工具非常有作用。
常用属性：
name:可选，表示数据库表中该字段的名称，默认情形属性名称一致
nullable:可选，表示该字段是否允许为null,默认为true
unique:可选，表示该字段是否为唯一标识，默认为false
length:可选，表示该字段的大小，仅对String类型的字段有效，默认值225，主键不能使用默认值
insertable:可选，表示在ORM框架执行插入操作时，该字段是否应出现INSERTRT语句中，默认为true
updateable:可选，表示在ORM框架执行更新操作时，该字段是否应该出现在UPDATE语句中，默认为true。对于已经创建
就不可以更改的字段，该属性非常有用
@Embedded
@Embedded是注释属性的，表示该属性的类是嵌入类。
注意：同时嵌入类也必须标注@Embeddable注解
@EmbeddedId
@EmbeddedId使用嵌入式主键类实现复合主键
注意：嵌入式主键类必须实现Serializable接口、必须有默认的public无参数的构造方法、必须覆盖equals和hashCode方法
@Lob
@Version
@Basic
@Transient
可选，表示该属性并非一个到数据库表的字段的映射，ORM框架将忽略该属性，如果一个属性并非数据库表的字段映射，就
务必将其标示为@Transient，否则ORM框架默认其注解为@Basic
实例：
hibernate.properties配置：
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<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> <!-- <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql:///hibernate_struts_stumanager</property> --> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/mypage</property> <property name="hibernate.connection.username">root</property> <property name="hibernate.connection.password">root</property> <property name="hibernate.show_sql">false</property> <property name="hibernate.hbm2ddl.auto">create</property> <!-- <property name="hibernate_current_session_context_class">thread</property> --> <property name="current_session_context_class">thread</property> <mapping class="com.entity.Students"/> </session-factory> </hibernate-configuration> |
实体类Student：
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package com.entity; import java.io.Serializable; import java.util.Date; import javax.persistence.Column; import javax.persistence.Embedded; import javax.persistence.EmbeddedId; import javax.persistence.Entity;//JPA注解 import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; import javax.persistence.Transient; import org.hibernate.annotations.GenericGenerator; /* * 学生实体类 *///@Entity// //@Entity(name="t_students")//如果不添加名字，则默认与实体类名字相同，如果想要自行设置表明，就需要自己进行添加 @Entity@Table(name="t_students1",schema="mypage") public class Students implements Serializable{ @Id// @GeneratedValue // @GeneratedValue(strategy=GenerationType.AUTO)//与@GeneratedValue结果相同，字符串类型不能指定为AUTO类型 // private int sid; //学号 // @GeneratedValue(generator="sid") // @GenericGenerator(name="sid",strategy="assigned") // @Column(length=11) // private String sid; @EmbeddedId private StudentPK pk; // @Id // // @Column(length=11) private String sname;//姓名 private String gender;//性别 private Date birthday;//出生日期 private String major;//专业 private Address add; @Transient //表示该字段不会被ORM映射到表里的字段 private double salary;//薪水 public Students(){ } public Students(StudentPK pk, String sname, String gender, Date date, String major,Address add,double salary) { // super(); this.pk = pk; this.sname = sname; this.gender = gender; this.birthday = date; this.major = major; this.add = add; this.salary = salary; } public StudentPK getPk() { return pk; } public void setPk(StudentPK pk) { this.pk = pk; } public String getSname() { return sname; } public void setSname(String sname) { this.sname = sname; } public String getGender() { return gender; } public void setGender(String gender) { this.gender = gender; } public Date getBirthday() { return birthday; } public void setBirthday(Date birthday) { this.birthday = birthday; } public String getMajor() { return major; } public void setMajor(String major) { this.major = major; } public Address getAdd() { return add; } public void setAdd(Address add) { this.add = add; } public double getSalary() { return salary; } public void setSalary(double salary) { this.salary = salary; } } |
StudentPK实体类：
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package com.entity; import java.io.Serializable; import javax.persistence.Column; import javax.persistence.Embeddable; @Embeddablepublic class StudentPK implements Serializable{ /** * */ private static final long serialVersionUID = 1L; @Column(length=18) private String id;//身份证号 @Column(length=8) private String sid;//学号 public StudentPK(){ } public StudentPK(String id, String sid) { this.id = id; this.sid = sid; } public String getId() { return id; } public void setId(String id) { this.id = id; } public String getSid() { return sid; } public void setSid(String sid) { this.sid = sid; } @Override public boolean equals(Object obj) { // TODO Auto-generated method stub return super.equals(obj); } @Override public int hashCode() { // TODO Auto-generated method stub return super.hashCode(); } } |
地址类：
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package com.entity; import javax.persistence.Embeddable; import javax.persistence.Embedded; // 地址类 @Embeddable //表示是一个嵌入类，这个类的对象在另一个实体类中充当属性 public class Address { private String postCode;//邮编 private String address;//地址 private String phone;//联系电话 public Address(){ } public Address(String postCode, String address, String phone) { this.postCode = postCode; this.address = address; this.phone = phone; } public String getPostCode() { return postCode; } public void setPostCode(String postCode) { this.postCode = postCode; } @Embedded public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } public String getPhone() { return phone; } public void setPhone(String phone) { this.phone = phone; } } |
测试类：
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package com.entity; import java.util.Date; import java.util.EnumSet; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.Transaction; import org.hibernate.cfg.Configuration; import org.hibernate.service.ServiceRegistry; import org.hibernate.service.ServiceRegistryBuilder; import org.hibernate.tool.hbm2ddl.SchemaExport; import org.junit.Test; public class TestStudents { @Test public void testShemaExport(){ //创建hibernate配置对象 Configuration config = new Configuration().configure(); //创建服务注册对象 ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry(); //生成SessionFactory SessionFactory sessionFactory = config.buildSessionFactory(serviceRegistry); SchemaExport export = new SchemaExport(config); export.create(true,true); } @Test public void addStudents(){ //创建hibernate配置对象 Configuration config = new Configuration().configure(); //创建服务注册对象 ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry(); //生成SessionFactory SessionFactory sessionFactory = config.buildSessionFactory(serviceRegistry); //创建会话 Session session = sessionFactory.getCurrentSession(); //创建事务 Transaction tx = session.beginTransaction(); Address add = new Address("700005","河南理工大学","15039117115"); StudentPK pk = new StudentPK("012345678912345678","55555555"); Students s = new Students(pk,"张三丰","男",new Date(),"太极拳",add,7899); session.save(s); tx.commit(); // SchemaExport export = new SchemaExport(config); // export.create(true,true); } } |
总结
以上就是本文关于hibernate属性级别注解实例代码的全部内容，希望对大家有所帮助。在此也非常希望大家对本站多多支持。
原文链接：http://blog.csdn.net/wojiaohuangyu/article/details/51768672
