当我将列表插入
mongodb时,有一个问题:
Exception in thread "main" java.lang.IllegalArgumentException: can't serialize class mongodb.Person 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$MyCollection.insert(DBApiLayer.java:252) at com.mongodb.DBApiLayer$MyCollection.insert(DBApiLayer.java:211) at com.mongodb.DBCollection.insert(DBCollection.java:57) at com.mongodb.DBCollection.insert(DBCollection.java:87) at com.mongodb.DBCollection.save(DBCollection.java:716) at com.mongodb.DBCollection.save(DBCollection.java:691) at mongodb.MongoDB.main(MongoDB.java:45)
类Person定义如下:
class Person{ private String name; public Person(String name){ this.name = name; } public String getName() { return name; } public void setName(String name) { this.name = name; } }
程序是:
DBCollection coll = db.getCollection("test"); DBObject record = new BasicDBObject(); List<Person> persons= new ArrayList<Person>(); persons.add(new Person("Jack")); record.put("person",persons); coll.save(record);
我找不到谷歌的答案,所以请帮助我.
解决方法
只需在Person类中实现
Serializable界面.
在你的类中定义一个serialVersionUID也是很好的.
AFAIK,在Java中创建POJO类时,类应该是可序列化的,如果要通过某些流传输,具有默认构造函数,并允许使用getter和setter方法访问属性/字段.