Question

我使用的是netbean，这是我的代码。但是当我运行代码时没有错误，并且没有数据保存在firebase中。我已经在google firebsae教程https://firebase.google.com/docs/database/admin/save-data的帮助下完成了这项工作。那么我的代码有什么问题。或者还有其他好的方法吗

package com.recomm.mavenrec.algorithm.firebaseConnection;

import com.google.firebase.FirebaseApp;
import com.google.firebase.FirebaseOptions;
import com.google.firebase.auth.FirebaseCredentials;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import com.recomm.mavenrec.Entity.Book;
import com.recomm.mavenrec.Entity.Hospital;
import java.io.FileInputStream;
import java.io.FileNotFoun## Heading ##dException;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;


public class FirebaseConnection {

    public void initiainzeSDK() {
        FileInputStream serviceAccount;
        try {
            serviceAccount = new FileInputStream("myJson.json");
            FirebaseOptions options = new FirebaseOptions.Builder()                        .setCredential(FirebaseCredentials.fromCertificate(serviceAccount))
                .setDatabaseUrl("https://adsnavigator-bc363.firebaseio.com/")
                .build();

            FirebaseApp.initializeApp(options);
        } catch (FileNotFoundException foe) {
            System.out.println(foe.getMessage());
        } catch (IOException ioe) {
            System.out.println(ioe.getMessage());
        }
    }

    public void authrnticate() {
        DatabaseReference ref = FirebaseDatabase
            .getInstance()
            .getReference("restricted_access/secret_document");
    ref.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
               Object document = dataSnapshot.getValue();
               System.out.println(document);
            }

            @Override
            public void onCancelled(DatabaseError error) {
                throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
            }
        });
    }

    public void writeTOFb() {
        FirebaseDatabase database = FirebaseDatabase.getInstance();
        DatabaseReference ref = database.getReference("rec");
        System.out.println(ref);
        DatabaseReference usersRef = ref.child("abc");
        System.out.println(usersRef);
        Map<String, Hospital> users = new HashMap<>();
        users.put("alanisawesome", new Hospital("abc", "sfsf", 1f));
        users.put("gracehop", new Hospital("xyz", "rde", 2f));
        System.out.println(users);
        usersRef.setValue(users);

    }}

`

Answer 1

您可能忘记将数据库写入规则更改为".write": true，您可以添加此规则并检查其中的错误。

usersRef.setValue(users, new DatabaseReference.CompletionListener() {
    @Override
    public void onComplete(DatabaseError databaseError, DatabaseReference databaseReference) {
        if (databaseError != null) {
            System.out.println("Data could not be saved " + databaseError.getMessage());
        } else {
            System.out.println("Data saved successfully.");
        }
    }
});

Answer 2

这是因为程序在firebase操作完成之前终止。您可以尝试添加计时器任务或线程以在程序中运行，以便应用程序不会被终止。

如何将数据从java应用程序保存到firebase

2 个答案: