Hibernate 注解映射

首先要创建要映射的实体类

一对多映射，一个人可以有多个收货地址

User.java

package star.july.b_annotation;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.Table;
/*** 使用注解映射*/
/*** @author Starjuly**/
//实体类
@Entity
//表名称
@Table(name="t_user")
public class User {@Id//自增长@GeneratedValue@Columnprivate int id;@Column(name="uName")private String name;//一对多连接//级联操作：CascadeType.ALL//主键维护策略：mappedBy:把关联维护权交给Address的user@OneToMany(cascade={CascadeType.ALL},mappedBy="user")//加入外键//使用mappedBy后就不能使用JoinColumn和JoinTable了
//  @JoinColumn(name="uid")private Set<Address> address = new HashSet<Address>();public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Set<Address> getAddress() {return address;}public void setAddress(Set<Address> address) {this.address = address;}}Address.java
package star.july.b_annotation;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
@Entity
@Table(name="t_address")
public class Address {@Id@GeneratedValue@Columnprivate int id;@Column(name="adsName")private String name;@Columnprivate String address;public String getAddress() {return address;}public void setAddress(String address) {this.address = address;}//多对一连接@ManyToOne@JoinColumn(name="uid")private User user = new User();public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public User getUser() {return user;}public void setUser(User user) {this.user = user;}}

再要hibernate.cfg.xml中配置映射类

测试类，包括一对多，多对多，一对一

package star.july.b_annotation;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;
import star.july.util.HibernateUtil;
//测试注解配置
public class TestDemo {//一对多连接@Testpublic void test(){Session session = HibernateUtil.getSession();Transaction ts = session.getTransaction();try{ts.begin();User u = new User();u.setName("徐凤年");Address ads = new Address();ads.setName("姜妮");ads.setAddress("北凉龙虎山");Address ads2 = new Address();ads2.setName("婓南苇");ads2.setAddress("北凉胭脂郡");u.getAddress().add(ads);u.getAddress().add(ads2);ads.setUser(u);ads2.setUser(u);session.save(u);ts.commit();}catch(Exception e ){e.printStackTrace();ts.rollback();}}//一对多连接@Testpublic void test2(){Session session = HibernateUtil.getSession();Transaction ts = session.getTransaction();try{ts.begin();Student s1 = new Student();s1.setName("小火");Student s2 = new Student();s2.setName("小火");Course c1 = new Course();c1.setName("java开发");Course c2 = new Course();c2.setName("java开发");s1.getCourse().add(c1);s1.getCourse().add(c2);s2.getCourse().add(c1);c1.getStudent().add(s1);c1.getStudent().add(s2);c2.getStudent().add(s1);session.save(s1);session.save(s2);session.save(c1);session.save(c2);ts.commit();}catch(Exception e ){e.printStackTrace();ts.rollback();}}//一对一连接@Testpublic void test3(){Session session = HibernateUtil.getSession();Transaction ts = session.getTransaction();try{ts.begin();Person p1 = new Person();p1.setName("左莫");Person p2 = new Person();p2.setName("杨紫");IdCard c1 = new IdCard();c1.setName("232443453");IdCard c2 = new IdCard();c2.setName("5687651543");p1.setCard(c1);p2.setCard(c2);c1.setPerson(p1);c2.setPerson(p2);session.save(p1);session.save(p2);session.save(c1);session.save(c2);ts.commit();}catch(Exception e ){e.printStackTrace();ts.rollback();}}
}

接下来是多对多的注解映射

Course
package star.july.b_annotation;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;
@Entity
@Table(name="t_course")
public class Course {@Id@GeneratedValue@Columnprivate int id;@Column(name="cName")private String name;@ManyToMany(mappedBy="course",cascade={CascadeType.ALL})/*@JoinTable(//中间表的表名name="student_course",//当前表的外键joinColumns=@JoinColumn(name="cid"),//关联表的外键inverseJoinColumns=@JoinColumn(name="sid"))*/private Set<Student> student = new HashSet<Student>();public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Set<Student> getStudent() {return student;}public void setStudent(Set<Student> student) {this.student = student;}}Student..java
package star.july.b_annotation;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;
import org.hibernate.annotations.CascadeType;
@Entity
@Table(name="t_student")
public class Student {@Id@GeneratedValue@Columnprivate int id;@Column(name="sName")private String name;@ManyToMany@JoinTable(//中间表的表名name="student_course",//当前表的外键joinColumns=@JoinColumn(name="sid"),//关联表的外键inverseJoinColumns=@JoinColumn(name="cid"))private Set<Course> course = new HashSet<Course>();public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Set<Course> getCourse() {return course;}public void setCourse(Set<Course> course) {this.course = course;}}

最后是一对一的注解映射

人和身份证

摘取其中最重要的代码片段：

Person.java

@OneToOne(cascade={CascadeType.ALL},mappedBy="person")

private IdCard card;

IdCard.java

@OneToOne

//外键唯一

@JoinColumn(name="uid",unique=true)

private Person person ;

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