mongodb morphia關聯查詢一例

 1 //...此處省略了import...
 2 /**
 3  * Created by shenzhigang on 4/15/16.
 4  */
 5 public class Main {
 6     public static void main(String[] args) {
 7         Datastore datastore;
 8         final Morphia morphia = new Morphia();
 9         morphia.mapPackage("com.bdb.datatypes.common.po");
10         datastore = morphia.createDatastore(new MongoClient("localhost", 27017), "test001");
11         datastore.ensureIndexes();
12 
13         Student student = new Student();
14         student.setName("沈志剛");
15         student.setAge(30);
16 
17         School school = new School();
18         school.setName("蘇州小學");
19         school.setAddress("蘇州市");
20         datastore.save(school);
21 
22         student.setSchool(school);
23         datastore.save(student);
24 
25         List<Key<School>> schools =datastore.createQuery(School.class).field("name").equal("蘇州小學").asKeyList();
26         List<Student> studentList =  datastore.find(Student.class).field("school").in(schools).asList();
27     }
28 }
29 
30 @Entity
31 class Student {
32     @Id
33     private ObjectId objectId ;
34     private String name;
35     private int age;
36     @Reference
37     private School school;
38 　　//...此處省略了get set.... 
39 }
40 
41 @Entity
42 class School {
43     @Id
44     private ObjectId objectId;
45     private String address;
46     private String name;
47 　　//....此處省略了get set...
48 }
49