Hibernate，JPA注解@OneToMany

Hibernate，JPA注解@OneToMany_Map

阅读量：6037 次

发布时间：2019-06-20

本文共 10123 字，大约阅读时间需要 33 分钟。

用例代码如下：

数据库DDL语句

1，CAT表

1 create table CAT 2 ( 3   id          VARCHAR2(32 CHAR) not null, 4   create_time TIMESTAMP(6), 5   update_time TIMESTAMP(6), 6   cat_name    VARCHAR2(255 CHAR), 7   first_name  VARCHAR2(255 CHAR), 8   last_name   VARCHAR2(255 CHAR), 9   version     NUMBER(10) not null10 )

2，HOBBY表

1 create table HOBBY2 (3   id          VARCHAR2(32 CHAR) not null,4   create_time TIMESTAMP(6),5   update_time TIMESTAMP(6),6   name        VARCHAR2(255 CHAR),7   cat_id      VARCHAR2(32 CHAR)8 )

hibernate.cfg.xml

1 
      2  5 
     
       6     
      
        7         
        8         
       
        org.hibernate.dialect.Oracle10gDialect
        9         
       
        oracle.jdbc.OracleDriver
       10         
       
        jdbc:oracle:thin:@127.0.0.1:1521:orcl
       11         
       
        wxuatuser
       12         
       
        xlh
       13         
       
        true
       14         
       15         
       
        update
       16         
       17         18         
       19         
       20         21     
      22

java类

实体类 - 基类

1 package model; 2 import java.io.Serializable; 3 import java.util.Date; 4 import javax.persistence.Column; 5 import javax.persistence.GeneratedValue; 6 import javax.persistence.Id; 7 import javax.persistence.MappedSuperclass; 8 import org.hibernate.annotations.GenericGenerator; 9 /**10  * 实体类 - 基类11  */12 @MappedSuperclass13 public class BaseEntity implements Serializable {14 15     private static final long serialVersionUID = -6718838800112233445L;16 17     private String id;// ID18     private Date create_time;// 创建日期19     private Date update_time;// 修改日期20     @Id21     @Column(length = 32, nullable = true)22     @GeneratedValue(generator = "uuid")23     @GenericGenerator(name = "uuid", strategy = "uuid")24     public String getId() {25         return id;26     }27     public void setId(String id) {28         this.id = id;29     }30     @Column(updatable = false)31     public Date getCreate_time() {32         return create_time;33     }34     public void setCreate_time(Date create_time) {35         this.create_time = create_time;36     }37     public Date getUpdate_time() {38         return update_time;39     }40     public void setUpdate_time(Date update_time) {41         this.update_time = update_time;42     }43     @Override44     public int hashCode() {45         return id == null ? System.identityHashCode(this) : id.hashCode();46     }47     @Override48     public boolean equals(Object obj) {49         if (this == obj) {50             return true;51         }52         if (obj == null) {53             return false;54         }55         if (getClass().getPackage() != obj.getClass().getPackage()) {56             return false;57         }58         final BaseEntity other = (BaseEntity) obj;59         if (id == null) {60             if (other.getId() != null) {61                 return false;62             }63         } else if (!id.equals(other.getId())) {64             return false;65         }66         return true;67     }68 }

实体类

Cat.java

1 package b10_OneToMany_Map; 2 import java.util.Map; 3 import javax.persistence.AttributeOverride; 4 import javax.persistence.AttributeOverrides; 5 import javax.persistence.CascadeType; 6 import javax.persistence.Column; 7 import javax.persistence.Embedded; 8 import javax.persistence.Entity; 9 import javax.persistence.FetchType;10 import javax.persistence.MapKey;11 import javax.persistence.OneToMany;12 import javax.persistence.Version;13 import model.BaseEntity;14 import org.hibernate.annotations.DynamicInsert;15 import org.hibernate.annotations.DynamicUpdate;16 17 @Entity18 @DynamicInsert19 @DynamicUpdate20 public class Cat extends BaseEntity{21     /**22      * 实体类23      */24     private static final long serialVersionUID = -2776330321385582872L;25     26     private Map
     
       hobbies;27 28     private String cat_name;29     private Name name;30     private int version;31 32     @Version33     public int getVersion() {34         return version;35     }36 37     public void setVersion(int version) {38         this.version = version;39     }40 41     public String getCat_name() {42         return cat_name;43     }44 45     public void setCat_name(String cat_name) {46         this.cat_name = cat_name;47     }48 49     @Embedded50     @AttributeOverrides({51             @AttributeOverride(name = "first_name", column = @Column(name = "first_name")),52             @AttributeOverride(name = "last_name", column = @Column(name = "last_name")) })53     public Name getName() {54         return name;55     }56 57     public void setName(Name name) {58         this.name = name;59     }60     /*61      * mappedBy属性：62      * 如果关系是单向的，则该关联提供程序确定拥有该关系的字段。63      * 如果关系是双向的，则将关联相反（非拥有）方上的 mappedBy 元素设置为拥64      * 有此关系的字段或属性的名称65      */66     @OneToMany(mappedBy = "cat", cascade = { CascadeType.ALL }, fetch = FetchType.EAGER)67     @MapKey(name="id")68     public Map
      
        getHobbies() {69         return hobbies;70     }71 72     public void setHobbies(Map
       
         hobbies) {73         this.hobbies = hobbies;74     }75 }

Hobby.java

1 package b10_OneToMany_Map; 2 import javax.persistence.Entity; 3 import javax.persistence.JoinColumn; 4 import javax.persistence.ManyToOne; 5 import model.BaseEntity; 6  7 @Entity 8 public class Hobby extends BaseEntity { 9     /**10      * 实体类11      */12     private static final long serialVersionUID = 4921844599282935594L;13     14     private String name;15     private Cat cat;16     17     public String getName() {18         return name;19     }20     public void setName(String name) {21         this.name = name;22     }23     @ManyToOne24     @JoinColumn(name = "CAT_ID")25     public Cat getCat() {26         return cat;27     }28     public void setCat(Cat cat) {29         this.cat = cat;30     }31 }

组件类

1 package b10_OneToMany_Map; 2 import java.io.Serializable; 3 import javax.persistence.Embeddable; 4  5 @Embeddable 6 public class Name implements Serializable { 7     /** 8      * 嵌入式组建 9      */10     private static final long serialVersionUID = -2776330321385582872L;11     12     private String first_name;13     private String last_name;14     public String getFirst_name() {15         return first_name;16     }17     public void setFirst_name(String first_name) {18         this.first_name = first_name;19     }20     public String getLast_name() {21         return last_name;22     }23     public void setLast_name(String last_name) {24         this.last_name = last_name;25     }26 }

Dao

1 package daoUtil; 2 import org.hibernate.HibernateException; 3 import org.hibernate.Session; 4 import org.hibernate.SessionFactory; 5 import org.hibernate.Transaction; 6 import org.hibernate.cfg.Configuration; 7 import org.hibernate.service.ServiceRegistry; 8 import org.hibernate.service.ServiceRegistryBuilder; 9 10 public class HibernateUtil {11 12     private static final SessionFactory sessionFactory;13 14     static {15         try {16             Configuration cfg = new Configuration().configure();17             ServiceRegistry serviceRegistry = new ServiceRegistryBuilder()18                     .applySettings(cfg.getProperties()).buildServiceRegistry();19             sessionFactory = cfg.buildSessionFactory(serviceRegistry);20         } catch (Throwable ex) {21             throw new ExceptionInInitializerError(ex);22         }23     }24 25     public static Session getSession() throws HibernateException {26         return sessionFactory.openSession();27     }28 29     public static Object save(Object obj){30         Session session = HibernateUtil.getSession();31         Transaction tx = null;32         try {33             tx = session.beginTransaction();34             session.save(obj);35             tx.commit();36         } catch (RuntimeException e) {37             if (tx != null) {38                 tx.rollback();39             }40             throw e;41         } finally {42             session.close();43         }44         return obj;45     }46     47     public static void delete(Class
      clazz,String id){48         Session session = HibernateUtil.getSession();49         Transaction tx = null;50         try {51             tx = session.beginTransaction();52             Object obj = session.get(clazz,id);53             session.delete(obj);54             tx.commit();55         } catch (RuntimeException e) {56             if (tx != null) {57                 tx.rollback();58             }59             throw e;60         } finally {61             session.close();62         }63     }64 }

main

1 package b10_OneToMany_Map; 2 import java.util.HashMap; 3 import java.util.Map; 4 import daoUtil.HibernateUtil; 5  6 public class Test_OneToMany_Map { 7  8     private Cat save(){ 9         10         Cat cat = new Cat();11         cat.setCat_name("b10_OneToMany_Map");12         cat.setName(new Name());13         14         Map
     
       hobbies = new HashMap
      
       ();15         Hobby hobby1 = new Hobby();16         hobby1.setName("足球");17         hobbies.put("1",hobby1);18         19         Hobby hobby2 = new Hobby();20         hobby2.setName("篮球");21         hobbies.put("2",hobby2);22         23         cat.setHobbies(hobbies);24         hobby1.setCat(cat);25         hobby2.setCat(cat);26         27         HibernateUtil.save(cat);28         return cat;29     }30     31     public static void main(String[] args) {32         33         Cat cat = new Test_OneToMany_Map().save();34         35         Cat cat1 = (Cat)HibernateUtil.getSession().get(Cat.class, cat.getId());36         System.out.println(cat1.getId());37         38         Map
       
         map = cat1.getHobbies();39         for (Map.Entry
        
          entry : map.entrySet()) {40             System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue().getName());41         }42         // delete43 //        HibernateUtil.delete(Cat.class,cat1.getId());44     }45 }