如何序列化类? [英] how to serialize class?

问题描述

当我在mongodb中插入一个列表时，出现了一个问题:

When I insert a List into mongodb, there is a problem:

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)

Person类的定义如下:

the class Person is defined as follows:

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;
    }
}

程序为:

        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);

我找不到来自Google的答案，所以请帮助我.

I can't find the answer from google, so please help me.

推荐答案

只需实现可序列化接口.

另外，在您的课程中定义一个serialVersionUID也很好.

Also it will be good to define a serialVersionUID in your class.

AFAIK，在用Java创建POJO类时，该类应该是可序列化的，如果要通过某个流进行传输，它具有默认构造函数，并允许使用getter和setter方法访问属性/字段.

AFAIK, while creating POJO class in java, the class should be serializable, if it is going to be transfered over some stream, have a default constructor, and allows access to properties/fields using getter and setter methods.

您可能有兴趣阅读以下内容:发现Java序列化API的秘密

You might be interested in reading this: Discover the secrets of the Java Serialization API

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