Question

您好我正在尝试检索用户女巫的角色是基于另一个文档，我在用户文档中将此角色的参考作为对象列表

当这个被解雇时我犯了一个错误

List<Document> listRoles = (List<Document>) document.get("listRole");

com.mongodb.DBRef无法强制转换为org.bson.Document

{
    "_id" : ObjectId("5a8bf269e1147736b4a7d06c"),
    "_class" : "fr.anasys.testsecuritymongodb.models.User",
    "username" : "hamou",
    "password" : "amroun",
    "actived" : true,
    "listRole" : [ 
        {
            "$ref" : "role",
            "$id" : ObjectId("5a8bf269e1147736b4a7d06a")
        }, 
        {
            "$ref" : "role",
            "$id" : ObjectId("5a8bf269e1147736b4a7d06b")
        }
    ]
}


    MongoDatabase database = mongoClient.getDatabase("rdproject2");
    MongoCollection<Document> collection = database.getCollection("User");

    Document document = collection.find(Filters.eq("username",email)).first();

    if(document!=null) {

        String username = document.getString("username");
        String password = document.getString("password");
        boolean actived = document.getBoolean("actived");
        List<Document> listRoles = (List<Document>) document.get("listRole");

        List<RefId> listRefIds = new ArrayList<>();

        for (Document refId :listRoles ) {
           listRefIds.add(new RefId(refId.getString("ref"),refId.getString("id" )));

        }

Answer 1

根据Resolve DBRef into Json，您可以将文档解码为JSON。

$ zip -r -X stuff.zip stuff/
updating: stuff/ (stored 0%)
updating: stuff/stuff1.txt (stored 0%)
updating: stuff/stuff2.txt (stored 0%)

$ shasum stuff.zip
1ed228b16d1ee803f26a8b1419f2eb3bf7fcb9f5  stuff.zip

$ zip -r -X stuff.zip stuff/
updating: stuff/ (stored 0%)
updating: stuff/stuff1.txt (stored 0%)
updating: stuff/stuff2.txt (stored 0%)

$ shasum stuff.zip
1ed228b16d1ee803f26a8b1419f2eb3bf7fcb9f5  stuff.zip

然后您可以从JSON解析以获取id字段。这可能不是解决问题的最佳方法，但这就是我现在正在做的事情。

com.mongodb.DBRef无法强制转换为org.bson.Document

1 个答案: