java - 如何将 Firebase 数据转换为自定义 Java 对象？

Question

我一直在阅读 Firebase 文档，但它只显示了简单的示例。我需要做的是从数据库的根获取所有数据并将其存储到一组自定义 Java 对象中(目前，我只是尝试将一项调查放入一个对象中)。根的每个子项都是一个调查，我有一个部分设置的类来接收数据。

我知道我使用此代码:

mDatabase.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for (DataSnapshot childSnapshot : dataSnapshot.getChildren()) {
            Survey s = childSnapshot.getValue(Survey.class);
            s.toString();
        }
    }

这是我的 Survey.java 类。我不确定如何在 Firebase 中镜像 Survey 对象的结构:

import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;

/*  This class stores one survey from the database  */
public class Survey implements Serializable {
    String name;
    String company;
    String description;
    String num_questions;
    String user;
    //HashMap<String,ArrayList<String>> question_strings; // Stores question title as key, with an arraylist of answer choices as the value

    public Survey() { }

    public Survey(String name, String company, String description, HashMap<String,ArrayList<String>> question_strings)
    {
        this.name = name;
        this.company = company;
        this.description = description;
        //this.question_strings = question_strings;
    }

    public void setName(String name) { this.name = name; }
    public void setCompany(String company) { this.company = company;}
    public void setDescription(String description) { this.description = description;}
    public void setNumQuestions(String num) { this.num_questions = num;}
    public void setUser(String user) { this.user = user;}

    public String getName() { return this.name;}
    public String getCompany() { return this.company;}
    public String getDescription() { return this.description;}
    public String getNumQuestions() { return this.num_questions;}
    public String getUser() { return this.user;}

public String toString()
{
    System.out.println("Name: " + name);
    System.out.println("Company: " + company);
    System.out.println("Description: " + description);
    System.out.println("Num questions: " + num_questions);


    return "";
}

}

最后，这是显示数据库中对象结构的屏幕截图:

我应该如何构建 Survey 类以与 Firebase 配合使用？

Answer 1

question_answers 看起来像 List<List<String>>大部头书。你尝试过吗？