java - 将类(class)保存到 firebase

Question

我的类是CredicardinfoObject.class

public class CreditcardinfoOjbect implements Serializable {
    private static final long serialVersionUID = 1L;

    public static String title;
    public static String startTime;
    public static String endTime;
    public static String day;

}

这个类只有静态属性。不需要实例化。

在我的 ma​​inActivity.class 中，我想设置类的值，然后存储这个 firebase 数据库。这是我的 ma​​inActivity.class。

    CreditcardinfoOjbect.title = "foo";
    CreditcardinfoOjbect.startTime = "bar";
    CreditcardinfoOjbect.day = "1";
    CreditcardinfoOjbect.endTime = "2";

    final FirebaseDatabase database = FirebaseDatabase.getInstance();
    String uid = "";
    FirebaseAuth auth = FirebaseAuth.getInstance();
    FirebaseUser user = auth.getCurrentUser();
    if (user != null) {
        uid = user.getUid();
    }
    DatabaseReference ref = database.getReference("users").child(uid).child("account").child("creditcards");

    HashMap<String, Class<CreditcardinfoOjbect>> hashMap = new HashMap<>();
    hashMap.put("card", CreditcardinfoOjbect.class);
    ref.setValue("card",hashMap );

不幸的是，这是行不通的。如何在 Firebase 中存储类的当前值？

Answer 1

首先，您需要向 POJO 类添加 Firebase 所需的无参数构造函数以及每个字段的公共(public) setter 和公共(public) getter，如下所示:

public class CreditCardInfoObject implements Serializable {
    private String title;
    privat eString startTime;
    private String endTime;
    private String day;

    public CreditCardInfoObject() {}

    public String getTitle() {return title;}
    public void setTitle(String title) {this.title = title;}

    public String getStartTime() {return startTime;}
    public void setStartTime(String startTime) {this.startTime = startTime;}

    public String getEndTime() {return endTime;}
    public void setEndTime(String endTime) {this.endTime = endTime;}

    public String getDay() {return day;}
    public void setDay(String day) {this.day = day;}
}

请注意，您不需要静态字段。另请注意，我将您的所有字段设置为私有(private)。在这种情况下，不需要 setter 和 getter。

现在，要设置 POJO 类的值，您需要创建 CreditCardInfoObject 类的新实例并使用公共(public) setter 。有了这个新对象，您可以像这样将它保存到 Firebase 实时数据库:

CreditcardinfoOjbect obj = new CreditcardinfoOjbect();
obj.setTitle("foo");
obj.setStartTime("bar");
obj.setEndTime("1");
obj.setDay("2");

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
String uid = "";
FirebaseAuth auth = FirebaseAuth.getInstance();
FirebaseUser user = auth.getCurrentUser();
if (user != null) {
    uid = user.getUid();
}
DatabaseReference ref = rootRef.child("users").child(uid).child("account").child("creditcards");
ref.setValue(obj);