1.今天遇見fastJson對mongodb的ID序列化失去精度的問題，今天講解下，並解決

如：id : 5baf10e781d589000175c5cd

fastJson裝換後變成：

2.為題分析

首先是出現serializers裡面並沒有mongodb的ObjectId的序列化類

3.問題解決

實現fastJson的ObjectSerializer

public class ObjectIdSerializer implements ObjectSerializer {

    public final static ObjectIdSerializer instance = new ObjectIdSerializer();

    @Override
    public void write(JSONSerializer serializer, Object object, Object fieldName, Type fieldType, int features) throws IOException {
        SerializeWriter out = serializer.out;

        if (object instanceof ObjectId) {
            ObjectId objectId = (ObjectId) object;
            out.writeString(objectId.toString());
            return;
        }
    }
}
 

SerializeConfig serializeConfig = SerializeConfig.getGlobalInstance();
serializeConfig.put(ObjectId.class , ObjectIdSerializer.instance);
JSON.toJSONString(map , serializeConfig);