您的位置：首页 > 产品设计 > UI/UE

Hibernate的命名查询（NamedQuery）

2015-10-18 00:00 579 查看
把HQL语句或SQL语句写在Hibernate实体类对应的映射文件中的使用。
打开Hibernate的Session的源码，我们可以看到有一个getNamedQuery(String name);的方法，如下：

1

2

3

4

5

6

7

8

9
/**



* Obtain an instance of <tt>Query</tt> for a named query string defined in the



* mapping file.



*



* @param queryName the name of a query defined externally



* @return Query



* @throws HibernateException



*/



public

Query getNamedQuery(String queryName)

throws

HibernateException;


这个方法就是可以执行定义在Hibernate实体类映射文件中的HQL或Sql语句。
具体做法下面我一一讲解，首先测试在映射文件中定义HQL语句。
我在User实体类的映射文件中定义了一个name为getUserByName的HQL查询语句，代码如下：

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19
<?

xml

version

=

"1.0"

?>


<!DOCTYPE hibernate-mapping PUBLIC



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



"D:\tools\hibernate\dtd\hibernate-mapping-3.0.dtd">


<

hibernate-mapping



package

=

"com.xigua.domain"

>



<

class

name

=

"User"

>


   

<

id

name

=

"id"

>


  

<

generator

class

=

"native"

/>


   

</

id

>


   

<

property

name

=

"name"

/>


   

<

property

name

=

"birthday"

/>



</

class

>





<!-- 定义一个查询，名称为getUserByName-->



<

query

name

=

"getUserByName"

>


   

<![CDATA[from User where name = :name]]>



</

query

>


</

hibernate-mapping

>


然后编写测试类使用Session中的getNamedQuery(String name)方法进行测试，代码如下：

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71
package

com.xigua.test;


import

java.util.Date;


import

java.util.List;


import

org.hibernate.Query;


import

org.hibernate.Session;


import

org.hibernate.Transaction;


import

com.xigua.domain.User;


import

com.xigua.utils.HibernateUtil;


public

class

Test9 {



public

static

void

main(String[] args) {


   

addUser();


   

String name =

"xigua"

;


   

List<User> list = namedQuery(name);


   

if

(list !=

null

&& !list.isEmpty()) {


  

for

(User user : list) {


 

System.out.println(user.getId() +

", "

+ user.getName() +

", "

+ user.getBirthday());


  

}


   

}



}





public

static

void

addUser() {


   

Session session =

null

;


   

Transaction tx =

null

;


   

try

{


  

session = HibernateUtil.getSession();


  

tx = session.beginTransaction();


  

User user =

new

User();


  

user.setName(

"xigua"

);


  

user.setBirthday(

new

Date());


  

session.save(user);


  


  

user =

new

User();


  

user.setName(

"donggua"

);


  

user.setBirthday(

new

Date());


  

session.save(user);


  

tx.commit();


   

}

catch

(Exception e) {


 &n
3ff0
bsp;

if

(tx !=

null

) {


 

tx.rollback();


  

}


   

}

finally

{


  

if

(session !=

null

) {


 

session.close();


  

}


   

}



}





public

static

List<User> namedQuery(String name) {


   

Session session =

null

;


   

try

{


  

session = HibernateUtil.getSession();


  

Query query = session.getNamedQuery(

"getUserByName"

);


  

query.setParameter(

"name"

, name);


  

return

query.list();


   

}

catch

(Exception e) {


  

e.printStackTrace();


   

}

finally

{


  

if

(session !=

null

) {


 

session.close();


  

}


   

}


   


   

return

null

;



}


}


在映射文件中除了可以定义HQL语句，也还是可以定义Sql语句的。
前面的User实体类的映射文件修改如下：

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24
<?

xml

version

=

"1.0"

?>


<!DOCTYPE hibernate-mapping PUBLIC



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



"D:\tools\hibernate\dtd\hibernate-mapping-3.0.dtd">


<

hibernate-mapping



package

=

"com.xigua.domain"

>



<

class

name

=

"User"

>


   

<

id

name

=

"id"

>


  

<

generator

class

=

"native"

/>


   

</

id

>


   

<

property

name

=

"name"

/>


   

<

property

name

=

"birthday"

/>



</

class

>





<!-- 定义一个查询，名称为getUserByName



<query name="getUserByName">


   

<![CDATA[from User where name = :name]]>



</query>



-->





<

sql-query

name

=

"getUserByName"

>


   

<![CDATA[select id, name from user where name = :name]]>



</

sql-query

>


</

hibernate-mapping

>


测试代码如下：

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75
package

com.xigua.test;


import

java.util.Date;


import

org.hibernate.Query;


import

org.hibernate.Session;


import

org.hibernate.Transaction;


import

com.xigua.domain.User;


import

com.xigua.utils.HibernateUtil;


public

class

Test10 {





public

static

void

main(String args[]) {


&
3ff0
nbsp;  

addUser();


   

String name =

"xigua"

;


   

User user =namedSqlQuery(name);


   

if

(user !=

null

) {


  

System.out.println(user.getId() +

", "

+ user.getName());


   

}


   



}





public

static

void

addUser() {


   

Session session =

null

;


   

Transaction tx =

null

;


   

try

{


  

session = HibernateUtil.getSession();


  

tx = session.beginTransaction();


  

User user =

new

User();


  

user.setName(

"xigua"

);


  

user.setBirthday(

new

Date());


  

session.save(user);


  


  

user =

new

User();


  

user.setName(

"donggua"

);


  

user.setBirthday(

new

Date());


  

session.save(user);


  

tx.commit();


   

}

catch

(Exception e) {


  

if

(tx !=

null

) {


 

tx.rollback();


  

}


   

}

finally

{


  

if

(session !=

null

) {


 

session.close();


  

}


   

}



}





public

static

User namedSqlQuery(String name) {


   

Session session =

null

;


   

try

{


  

session = HibernateUtil.getSession();


  

Query query = session.getNamedQuery(

"getUserByName"

);


  

query.setParameter(

"name"

, name);


  

Object[] obj = (Object[]) query.uniqueResult();


  

if

(obj !=

null

) {


 

User user =

new

User();


 

user.setId(Long.valueOf(obj[

0

].toString()));


 

user.setName(obj[

1

].toString());


 

return

user;


  

}


   

}

catch

(Exception e) {


  

e.printStackTrace();


3ff0

   

}

finally

{


  

if

(session !=

null

) {


 

session.close();


  

}


   

}


   


   

return

null

;



}


}


映射文件中还有些其它的配置，暂时还没具体搞懂，比如下面红色的代码：

1

2

3

4

5

6

7

8
<sql-query name=

"getUserByName"

>


   

<![CDATA[select id, name from user where name = :name]]>


   

<query-param name=

"name"

type=

"string"

/>


   

<

return

></

return

>


   

<

return

-join alias=

""

property=

""

></

return

-join>


   

<

return

-scalar column=

""

/>


   

<synchronize table=

""

/>



</sql-query>


还有一点像说明的是<query>跟<sql-query>的配置是可以放到<class>节点里面的。
我现在是放在<class>节点外面，表示全局可用，这里需要注意不要跟其它映射文件中定义的<query>或<sql-query>同名。
如果将<query>或<sql-query>放在<class>节点里面，在java代码中使用的时候需要将package名跟class名都写上，具体见下面配置的映射文件代码跟测试代码。
映射文件代码：

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23
<?

xml

version

=

"1.0"

?>


<!DOCTYPE hibernate-mapping PUBLIC



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



"D:\tools\hibernate\dtd\hibernate-mapping-3.0.dtd">


<

hibernate-mapping



package

=

"com.xigua.domain"

>



<

class

name

=

"User"

>


   

<

id

name

=

"id"

>


  

<

generator

class

=

"native"

/>


   

</

id

>


   

<
property

name

=

"name"

/>


   

<

property

name

=

"birthday"

/>


   


   

<!-- 定义一个查询，名称为getUserByName(这里将<query>放到<class>节点里面来)-->


   

<

query

name

=

"getUserByName"

>


  

<![CDATA[from User where name = :name]]>


   

</

query

>





</

class

>








</

hibernate-mapping

>


java测试代码

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71
package

com.xigua.test;


import

java.util.Date;


import

java.util.List;


import

org.hibernate.Query;


import

org.hibernate.Session;


import

org.hibernate.Transaction;


import

com.xigua.domain.User;


import

com.xigua.utils.HibernateUtil;


public

class

Test9 {



public

static

void

main(String[] args) {


   

addUser();


   

String name =

"xigua"

;


   

List<User> list = namedQuery(name);


   

if

(list !=

null

&& !list.isEmpty()) {


  

for

(User user : list) {


 

System.out.println(user.getId() +

", "

+ user.getName() +

", "

+ user.getBirthday());


  

}


   

}



}





public

static

void

addUser() {


   

Session session =

null

;


   

Transaction tx =

null

;


   

try

{


  

session = HibernateUtil.getSession();


  

tx = session.beginTransaction();


  

User user =

new

User();


  

user.setName(

"xigua"

);


  

user.setBirthday(

new

Date());


  

session.save(user);


  


  

user =

new

User();


  

user.setName(

"donggua"

);


  

user.setBirthday(

new

Date());


  

session.save(user);


  

tx.commit();


   

}

catch

(Exception e) {


  

if

(tx !=

null

) {


 

tx.rollback();


  

}


   

}

finally

{


  

if

(session !=

null

) {


 

session.close();


  

}


   

}



}





public

static

List<User> namedQuery(String name) {


   

Session session =

null

;


   

try

{


  

session = HibernateUtil.getSession();


  

Query query = session.getNamedQuery(

"com.xigua.domain.User.getUserByName"

);


  

query.setParameter(

"name"

, name);


  

return

query.list();


   

}

catch

(Exception e) {


  

e.printStackTrace();


   

}

finally

{


  

if

(session !=

null

) {


 

session.close();


  

}


   

}


   


   

return

null

;



}


3ff0

}


来自为知笔记(Wiz)
                                            

                                        

                        
                        内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理 点击这里给我发消息 
                    

                    

                    

                        

                         标签： 
                                                

                        

                    


                

            


            

                
相关文章推荐

                

                
            

        

        

            

            
            

                

                    
新的分享

                    

                        
                    

                

            


            

                

                    
章节导航