Hibernate实体映射配置(XML)简单三步完美配置

我们在使用Hibernate框架的时候,非常纠结的地方就是实体和表之间的映射,今天借助汤老师的思路写了小教程,以后配置不用纠结了!

 

第一步:写注释

  格式为:?属性,表达的是本对象与?的?关系。
  例:“department属性,本对象与Department的多对一”

第二步:拷模板

  

第三步:填空:

  name属性:属性名(注释中的第1问号)
  class属性:关联的实体类型(注释中的第2个问号)
  column属性:
    <many-to-one column="..">:一般可以写成属性名加Id后缀,如属性为department,则column值写成departmentId。
    一对多中的<key column="..">:从关联的对方(对方是多对一)映射中把column值拷贝过来。
    多对多中的<key column=“..”>:一般可以写成本对象的名加Id后缀,如本对象名为User,则写为userId。
    多对多中的<many-to-many column=“..”>:一般可以写为关联对象的名称加Id后缀。

 

应用实例:

  用户、角色、部门之间的关系映射

  用户: ID 、名称

  角色:ID、角色名、描述

  部门:ID、部门名

  关系:

    用户和角色是多对多关系,用户和部门是多对一关系,部门自关联是多对一/一对多关系

  测试代码:

    实体类:(写实体类时候一定不要忘记给每个属性添加setter、getter方法,否则创建不了sessionFactory等对象

     User.java

 1 package com.qcf.po;
 2 
 3 import java.util.HashSet;
 4 import java.util.Set;
 5 
 6 public class Depart {
 7     
 8     private int id;
 9     private String name;
10     //用户
11     Set<User> users=new HashSet<User>();
12     
13     //子类部门
14     Set<Depart> departs=new HashSet<Depart>();
15 
16     //父类部门
17     private Depart depart;
18     
19     
20     public Set<User> getUsers() {
21         return users;
22     }
23     public void setUsers(Set<User> users) {
24         this.users = users;
25     }
26     public Set<Depart> getDeparts() {
27         return departs;
28     }
29     public void setDeparts(Set<Depart> departs) {
30         this.departs = departs;
31     }
32     public Depart getDepart() {
33         return depart;
34     }
35     public void setDepart(Depart depart) {
36         this.depart = depart;
37     }
38     public int getId() {
39         return id;
40     }
41     public void setId(int id) {
42         this.id = id;
43     }
44     public String getName() {
45         return name;
46     }
47     public void setName(String name) {
48         this.name = name;
49     }
50     public Depart(int id, String name) {
51         super();
52         this.id = id;
53         this.name = name;
54     }
55     public Depart() {
56         super();
57     }
58     
59 
60 }
View Code

     Role.java

 1 package com.qcf.po;
 2 
 3 import java.util.HashSet;
 4 import java.util.Set;
 5 
 6 public class Role {
 7     
 8     private int id;
 9     private String name;
10     private String destion;
11     
12     //用户
13     Set<User> users=new HashSet<User>();
14     
15 
16     public Set<User> getUser() {
17         return users;
18     }
19     public void setUser(Set<User> users) {
20         this.users = users;
21     }
22     public int getId() {
23         return id;
24     }
25     public void setId(int id) {
26         this.id = id;
27     }
28     public String getName() {
29         return name;
30     }
31     public void setName(String name) {
32         this.name = name;
33     }
34     public String getDestion() {
35         return destion;
36     }
37     public void setDestion(String destion) {
38         this.destion = destion;
39     }
40     public Role(int id, String name, String destion) {
41         super();
42         this.id = id;
43         this.name = name;
44         this.destion = destion;
45     }
46     
47     public Set<User> getUsers() {
48         return users;
49     }
50     public void setUsers(Set<User> users) {
51         this.users = users;
52     }
53     public Role() {
54         // TODO Auto-generated constructor stub
55     }
56 }
View Code

     Depart.java

 1 package com.qcf.po;
 2 
 3 import java.util.HashSet;
 4 import java.util.Set;
 5 
 6 public class Depart {
 7     
 8     private int id;
 9     private String name;
10     //用户
11     Set<User> users=new HashSet<User>();
12     
13     //子类部门
14     Set<Depart> departs=new HashSet<Depart>();
15 
16     //父类部门
17     private Depart depart;
18     
19     
20     public Set<User> getUsers() {
21         return users;
22     }
23     public void setUsers(Set<User> users) {
24         this.users = users;
25     }
26     public Set<Depart> getDeparts() {
27         return departs;
28     }
29     public void setDeparts(Set<Depart> departs) {
30         this.departs = departs;
31     }
32     public Depart getDepart() {
33         return depart;
34     }
35     public void setDepart(Depart depart) {
36         this.depart = depart;
37     }
38     public int getId() {
39         return id;
40     }
41     public void setId(int id) {
42         this.id = id;
43     }
44     public String getName() {
45         return name;
46     }
47     public void setName(String name) {
48         this.name = name;
49     }
50     public Depart(int id, String name) {
51         super();
52         this.id = id;
53         this.name = name;
54     }
55     public Depart() {
56         super();
57     }
58     
59 
60 }
View Code

    映射文件:

     User.hbm.xml

 1 <?xml version="1.0"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC 
 3     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 4     "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 5 <hibernate-mapping 
 6     package="com.qcf.po">
 7     <class name="User" table="user"> 
 8         <id name="id">
 9             <generator class="native"></generator>
10         </id>
11         <property name="name" column="username" type="string"></property>
12         <property name="age"  column="userage" type="integer"></property>
13 
14         <!--depart属性,本对象与Depart的多对一  -->
15         <many-to-one name="depart" class="Depart" column="departId"></many-to-one>
16         
17         <!--roles属性,本对象与Role的多对多  -->
18         <set name="roles" table="user_role">
19             <key column="roleId"></key>
20             <many-to-many class="Role" column="userId"></many-to-many>
21         </set>
22     
23     </class>
24     
25     
26 </hibernate-mapping>

     Role.hbm.xml

 1 <?xml version="1.0"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC 
 3     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 4     "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 5 <hibernate-mapping 
 6     package="com.qcf.po">
 7     <class name="Role"> 
 8         <id name="id">
 9             <generator class="native"></generator>
10         </id>
11         <property name="name" column="rolename" type="string"></property>
12         <property name="destion" column="roledestion"></property>
13         
14         <!--users属性,本对象与User的多对多  -->
15         <set name="users" table="user_role">
16             <key column="userId"></key>
17             <many-to-many class="User" column="roleId"/>
18         </set>
19             
20     </class>
21     
22     
23 </hibernate-mapping>

    Depart.hbm.xml

 1 <?xml version="1.0"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC 
 3     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 4     "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 5 <hibernate-mapping 
 6     package="com.qcf.po">
 7     <class name="Depart"> 
 8         <id name="id">
 9             <generator class="native"></generator>
10         </id>
11         <property name="name" column="departname" type="string"></property>
12 
13         <!--users属性,本对象与User的一对多  -->
14         <set name="users">
15             <key column="departId"></key>
16             <one-to-many class="User"/>
17         </set>
18         
19         <!--departs属性,本对象与Depart(子类)的一对多  -->
20         <set name="departs">
21             <key column="departId"></key>
22             <one-to-many class="Depart"/>
23         </set>
24         
25         <!--depart属性,本对象与Depart(父类)的多对一  -->
26         <many-to-one name="depart" column="departId" class="Depart"></many-to-one>
27         
28     </class>
29     
30     
31 </hibernate-mapping>

   直接启动程序,或者获取sessionFactory对象即可在数据库中创建四张表。

 

  

郑重声明:本站内容如果来自互联网及其他传播媒体,其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享,并不代表本站赞同其观点和对其真实性负责,也不构成任何其他建议。