OA项目8:表映射关系及跟对象之间的关系处理

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一　之前我们写了两个功能，这两个功能之间没有什么关联关系。下面我们做的用户管理功能将和之前的两个功能有相应的关联关系，所以要先匹配之间的关联关系，然后才能够进行代码的编写，下图就是三个功能类之间的模型图，这有益于外面分析功能间的关系和编写修改功能代码：

 

二　将上面三个实体类全部写出来，具体如下：

 1 package cn.clear.oa.domain;

 2 

 3 import java.util.HashSet;

 4 import java.util.Set;

 5 

 6 public class User {

 7     private Long id;

 8     private String name;

 9     private String loginName;

10     private String gender;

11     private String phoneNumber;

12     private String email;

13     private String password;

14     private String description;

15     private Department department;

16     private Set<Role> roles = new HashSet<Role>();

17     public Set<Role> getRoles() {

18         return roles;

19     }

20     public void setRoles(Set<Role> roles) {

21         this.roles = roles;

22     }

23     public Long getId() {

24         return id;

25     }

26     public void setId(Long id) {

27         this.id = id;

28     }

29     public String getName() {

30         return name;

31     }

32     public void setName(String name) {

33         this.name = name;

34     }

35     public String getLoginName() {

36         return loginName;

37     }

38     public void setLoginName(String loginName) {

39         this.loginName = loginName;

40     }

41     public String getGender() {

42         return gender;

43     }

44     public void setGender(String gender) {

45         this.gender = gender;

46     }

47     public String getPhoneNumber() {

48         return phoneNumber;

49     }

50     public void setPhoneNumber(String phoneNumber) {

51         this.phoneNumber = phoneNumber;

52     }

53     public String getEmail() {

54         return email;

55     }

56     public void setEmail(String email) {

57         this.email = email;

58     }

59     public String getPassword() {

60         return password;

61     }

62     public void setPassword(String password) {

63         this.password = password;

64     }

65     public String getDescription() {

66         return description;

67     }

68     public void setDescription(String description) {

69         this.description = description;

70     }

71     public Department getDepartment() {

72         return department;

73     }

74     public void setDepartment(Department department) {

75         this.department = department;

76     }

77     

78     

79 }

User.java

 1 package cn.clear.oa.domain;

 2 

 3 import java.util.HashSet;

 4 import java.util.Set;

 5 

 6 public class Role {

 7 

 8     private Long id;

 9     private String name;

10     private String description;

11     private Set<User> users = new HashSet<User>();

12     public Long getId() {

13         return id;

14     }

15     public void setId(Long id) {

16         this.id = id;

17     }

18     public String getName() {

19         return name;

20     }

21     public void setName(String name) {

22         this.name = name;

23     }

24     public String getDescription() {

25         return description;

26     }

27     public void setDescription(String description) {

28         this.description = description;

29     }

30     public Set<User> getUsers() {

31         return users;

32     }

33     public void setUsers(Set<User> users) {

34         this.users = users;

35     }

36     

37     

38 }

Role.java

 1 package cn.clear.oa.domain;

 2 

 3 import java.util.HashSet;

 4 import java.util.Set;

 5 

 6 public class Department {

 7 

 8     private Long id;

 9     private String name;

10     private String description;

11     private Department parent;

12     private Set<User> users = new HashSet<User>();

13     private Set<Department> children = new HashSet<Department>();

14     

15     public Department getParent() {

16         return parent;

17     }

18     public void setParent(Department parent) {

19         this.parent = parent;

20     }

21     public Set<User> getUsers() {

22         return users;

23     }

24     public void setUsers(Set<User> users) {

25         this.users = users;

26     }

27     public Set<Department> getChildren() {

28         return children;

29     }

30     public void setChildren(Set<Department> children) {

31         this.children = children;

32     }

33     public Long getId() {

34         return id;

35     }

36     public void setId(Long id) {

37         this.id = id;

38     }

39     public String getName() {

40         return name;

41     }

42     public void setName(String name) {

43         this.name = name;

44     }

45     public String getDescription() {

46         return description;

47     }

48     public void setDescription(String description) {

49         this.description = description;

50     }

51     

52     

53 }

Department.java

三　分析三个类的关联关系，在映射文件中配置相应的属性，我将映射文件内容表于下面：

 1 <?xml version="1.0"?>

 2 <!DOCTYPE hibernate-mapping PUBLIC 

 3     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

 4     "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

 5 

 6 <hibernate-mapping package="cn.clear.oa.domain">

 7     <class name="User" table="oa_user">

 8         <id name="id"><generator class="native"/></id>

 9         <property name="name"/>

10         <property name="loginName"/>

11         <property name="gender"/>

12         <property name="phoneNumber"/>

13         <property name="email"/>

14         <property name="password"/>

15         <property name="description"/>

16         <!-- department属性，本类与Department的多对1关系 -->

17         <many-to-one name="department" class="Department" column="departmentId"></many-to-one>

18         <!-- roles属性，本类与Role的多对多关系 -->

19         <set name="roles" table="oa_user_role">

20             <key column="userId"></key>

21             <many-to-many class="Role" column="roleId"></many-to-many>

22         </set>

23     </class>

24 </hibernate-mapping>

User.hbm.xml

 1 <?xml version="1.0"?>

 2 <!DOCTYPE hibernate-mapping PUBLIC 

 3     "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

 4     "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

 5 

 6 <hibernate-mapping package="cn.clear.oa.domain">

 7     <class name="Role" table="oa_role">

 8         <id name="id">

 9             <generator class="native" />

10         </id>

11         <property name="name" />

12         <property name="description" />

13         <!-- users属性，本类与User的多对多 -->

14         <set name="users" table="oa_user_role">

15             <key column="roleId"></key>

16             <many-to-many class="User" column="userId"></many-to-many>

17         </set> 

18     </class>

19 </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://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

 5 

 6 <hibernate-mapping package="cn.clear.oa.domain">

 7     <class name="Department" table="oa_department">

 8         <id name="id"><generator class="native"/></id>

 9         <property name="name"/>

10         <property name="description"/>

11         <!-- users属性，本类与User的1对多 -->

12         <set name="users">

13             <key column="departmentId"></key>

14             <one-to-many class="User"/>

15         </set>

16         <!-- parent属性，本类与（上级）Department的多对1 -->

17         <many-to-one name="parent" class="Department" column="parentId"></many-to-one>

18         <!-- children属性，本类与（下级）Department的1对多 -->

19         <set name="children">

20             <key column="parentId"></key>

21             <one-to-many class="Department"/>

22         </set>

23     </class>

24 </hibernate-mapping>

Department.hbm.xml

　　总结出映射文件的写法，下面的内容就来概括：

　　例：<!--　users属性，本类与User类的一对多　-->

　　格式：a属性，本类与b的c。

　　解释：a为属性名，b为关联的对象名，c为对应的关系。

　　模板（以后在填写多表映射时可以以以此为模板）：

　　　　1）多对一：

　　　　　　<many-to-one name="a" class="b" column="a+Id"></many-to-one>

　　　　2）一对多：

　　　　　　<set name="a">

　　　　　　　　<key column="对应多对一中的column"></key>

　　　　　　　　<one-to-many class="b"/>

　　　　　　</set>

　　　　3）多对多：

　　　　　　<set name="a" table="oa_本类类名(小写)_b类名(小写)">

　　　　　　　　<key column="本类类名小写+Id"></key>

　　　　　　　　<many-to-many class="b" column="b类名+Id"></many-to-many>

　　　　　　</set>

四　以上做完后启动之前的测试类TestSpring.java中的测试SessionFactory的方法进行自动建表，如不报错，去数据库看看是否正确。