查询嵌套文档和 atrihute do 变量（MongoDB Java Driver 3.2）

Question

我有下面的数据，我正在尝试读取数据并将每个数据分配到变量中，但无法获取 info 中的数据，仍然给我 null 或空白 email 和 phone

    {
    "_id": ObjectId ( "56c570d904df6c51b463da54"),
    "Name": "John Smith"
    "Age": 31,
    "Info": {
        "Email", "john.smith@mail.com"
        "Phone", "+987654321"
    }
}

java代码下方

findAll.forEach (new Block <Document> () {

                @Override
                public void apply (Document document) {
                    String name = document.getString ( "name")!= null? document.getString ( "name"): "";
                    int age = document.getInteger ( "age")!= null? document.getInteger ( "age"): 0;
                    String email = document.getString ( "info.email")!= null? document.getString ( "info.email") "";
                    String phone = document.getString ( "info.phone")! = null? document.getString ( "info.phone") "";
                    Costumer costumer = new Costumer (name, age, email, phone);
                    System.out.println (costumer);
                }
            });

Answer 1

看起来很接近！代码中有几个错误：

将Null更改为null
您无法查找嵌套键，例如：document.getString( "info.email") 将不起作用。您应该将子文档分配给一个变量，然后尝试从中获取数据。

我还没有测试过，但我认为这样的东西应该效果更好：

findAll.forEach (new Block <Document> () {
    @Override
    public void apply (Document document) {
        String name = document.getString ("name")! = null? document.getString( "name") : "";
        int age = document.getInteger ( "age", 0);

        // Get the info subdocument
        Document info = document.get("info", Document.class);
        String email = "";
        String phone = "";
        if (info != null) {
          email = info.getString ("email")! = null? info.getString("email") : "";
          phone = info.getString ("phone")! = null? info.getString("phone") : "";
        }
        Costumer costumer = new Costumer (name, age, email, phone);
        System.out.println(costumer);
    }
});

希望对您有所帮助。

查询嵌套文档和 atrihute do 变量（MongoDB Java Driver 3.2）

Querying on nested documents and atrihute do variables (MongoDB Java Driver 3.2)

java

mongodb-java