将数组ArrayList <Model>存储到Java中的MongoDB中

Question

在我的Java Play框架应用程序中，我想将ArrayList值存储在mongoDB中。

我在JSON中有3个值，它们是loginid，phone，students;在那里学生是ArrayList。我在MongoDB中存储的数据是这样的：

{ "loginid" : "user@mail.com", "phone" : "", "students" : [{"firstName" : "Jesse", "lastName" : "Varnell", "age" : "15", "gender" : "M" }, { "firstName" : "John", "lastName" : "Doe", "age" : "13", "gender" : "F"}] } 

我使用蒙戈查询存储喜欢的值：

BasicDBObject searchQuery = new BasicDBObject(); 
BasicDBObject theUserObj = new BasicDBObject(); 

ArrayList<Student> student = new ArrayList<Student>(); 
if(studentArray != null && studentArray.size()>=0) { 
    Student stud = new Student(); 
    for(int i = 0; i < studentArray.size(); i++){ 
     stud = studentArray.get(i); 
     student.add(stud); 
    } 
} 
theUserObj.put("loginid", profile.loginid); 
theUserObj.put("phone", profile.phone); 
searchQuery.append("loginid", username); 
theUserObj.put("students", student); 

theUserCollection.update(searchQuery, theUserObj); //Got error on this line. 

我收到以下错误：

Execution exception (In /app/controllers/StudentInfo.java around line 176) 
IllegalArgumentException occured : can't serialize class models.Student 

play.exceptions.JavaExecutionException: can't serialize class models.Student 
    at play.mvc.ActionInvoker.invoke(ActionInvoker.java:237) 
    at Invocation.HTTP Request(Play!) 
Caused by: java.lang.IllegalArgumentException: can't serialize class models.Student 
    at org.bson.BasicBSONEncoder._putObjectField(BasicBSONEncoder.java:234) 
    at org.bson.BasicBSONEncoder.putIterable(BasicBSONEncoder.java:259) 
    at org.bson.BasicBSONEncoder._putObjectField(BasicBSONEncoder.java:198) 
    at org.bson.BasicBSONEncoder.putObject(BasicBSONEncoder.java:140) 
    at org.bson.BasicBSONEncoder.putObject(BasicBSONEncoder.java:86) 
    at com.mongodb.DefaultDBEncoder.writeObject(DefaultDBEncoder.java:27) 
    at com.mongodb.OutMessage.putObject(OutMessage.java:142) 
    at com.mongodb.DBApiLayer$MyCollection.update(DBApiLayer.java:346) 
    at com.mongodb.DBCollection.update(DBCollection.java:165) 
    at com.mongodb.DBCollection.update(DBCollection.java:197) 
    at com.mongodb.DBCollection.update(DBCollection.java:209) 
    at controllers.StudentInfo.doStoreProfile(StudentInfo.java:176) 
    at controllers.StudentInfo.storeUserProfile(StudentInfo.java:212) 
    at play.mvc.ActionInvoker.invokeWithContinuation(ActionInvoker.java:557) 
    at play.mvc.ActionInvoker.invoke(ActionInvoker.java:508) 
    at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:484) 
    at play.mvc.ActionInvoker.invokeControllerMethod(ActionInvoker.java:479) 
    at play.mvc.ActionInvoker.invoke(ActionInvoker.java:161) 

如何用ArrayList在MongoDB中使用Java存储值？

Answer 1

DBObject和实现类只能处理BSON类型，其中你不是Student类。

有很多框架可以映射|将域对象（如Student）转换为|来自BSON的代表和文件。由于您没有明显使用，您必须手动将每个Student自己转换为DBObject。

BasicDBObject searchQuery = new BasicDBObject("loginid", username); 
BasicDBObject theUserObj = new BasicDBObject(); 

List<Object> studentsDBList = new BasicDBList(); 

for (Student student : studentArray) { 
    DBObject studentDBObject = new BasicDBObject(); 
    studentDBObject.put("firstName", student.getFirstName()); 
    studentDBObject.put("lastName", student.getLastName()); 
    studentDBObject.put("age", student.getAge()); 
    studentDBObject.put("gender", student.getGender()); 
    studentsDBList.add(studentDBObject); 
} 

theUserObj.put("phone", profile.phone); 
theUserObj.put("students", studentsDBList); 

theUserCollection.update(searchQuery, theUserObj); 

另外请注意，你不必把loginid为theUserObj，因为你只查询它