Question

我想为用户发送到firebase数据库的每条消息存储public class MyApp { public static void main(String[] args) throws IOException { CredentialsProvider credsProvider = new BasicCredentialsProvider(); Credentials credentials = new UsernamePasswordCredentials("user@example.com", "secret"); credsProvider.setCredentials(AuthScope.ANY, credentials); HttpClientContext context = HttpClientContext.create(); context.setCookieStore(new BasicCookieStore()); context.setCredentialsProvider(credsProvider); CloseableHttpClient client = HttpClientBuilder.create() // my server requires this header otherwise it returns response with code 500 .setDefaultHeaders(Collections.singleton(new BasicHeader("x-requested-with", "XMLHttpRequest"))) .setTargetAuthenticationStrategy(new MyAuthStrategy()) .build(); String url = "https://example.com/some/resource"; String url2 = "https://example.com/another/resource"; // ======= REQUEST 1 ======= HttpGet request = new HttpGet(url); HttpResponse response = client.execute(request, context); String responseText = EntityUtils.toString(response.getEntity()); request.reset(); // ======= REQUEST 2 ======= HttpGet request2 = new HttpGet(url); HttpResponse response2 = client.execute(request2, context); String responseText2 = EntityUtils.toString(response2.getEntity()); request2.reset(); // ======= REQUEST 3 ======= HttpGet request3 = new HttpGet(url2); HttpResponse response3 = client.execute(request3, context); String responseText3 = EntityUtils.toString(response3.getEntity()); request3.reset(); client.close(); } }。这是正确的方法吗？

在我的代码中，我使用了以下内容。

MyAuthScheme.authenticate()

当我尝试运行我的应用时，我收到此错误。

Time Stamp

这是我的模型类，Message message = new Message(null, mUserName, downloadUrl.toString(),ServerValue.TIMESTAMP); messagesDatabaseReference.push().setValue(message);：

com.google.firebase.database.DatabaseException: Expected a Map while deserializing, but got a class java.lang.Long

Answer 1

我假设您从数据库中检索timestamp时收到错误消息。规则是，当您设置timestamp时，将其设置为Map，当您检索时，您将检索为Long。所以为了使它正确，我建议你使用这种方法：

public static String getTimeDate(long timeStamp){
    try{
        DateFormat dateFormat = getDateTimeInstance();
        Date netDate = (new Date(timeStamp));
        return dateFormat.format(netDate);
    }
    catch(Exception e){
        return "date";
    }
}

如果您只想检索日期，请使用以下方法：

static String getDate(long timeStamp){
    try{
        DateFormat dateFormat = getDateInstance();
        Date netDate = (new Date(timeStamp));
        return dateFormat.format(netDate);
    }
    catch(Exception e){
        return "date";
    }
}

当您检索timestamp时，将侦听器放在特定节点上并按照以下方式迭代地图：

if (entry.getKey().equals("timeStamp")) {
    Long timeStampLong = (Long) entry.getValue();
    String timeStamp = getDate(timeStampLong);
    ((TextView )findViewById(R.id.time_stamp)).setText(timeStamp);
}

希望它有所帮助。

Answer 2

我已将模型类Message改建为：

public class Message {

  private String text;
  private String name;
  private String photoUrl;
  private String dateAndTime;

  public Message(String text, String name, String photoUrl, String dateAndTime){
    this.text = text;
    this.name = name;
    this.photoUrl = photoUrl;
    this.dateAndTime = dateAndTime;
  }
  // getters and setters
}

在MainActivity中，我实施了以下内容，将时间戳和用户的消息发送到Firebase数据库。有效！

Date date = new Date();
SimpleDateFormat formatter = new SimpleDateFormat("EEE, MMM dd hh:mm a");
String dateAndTime = formatter.format(date);
Message message = new Message(mMessageEditText.getText().toString(), mUserName, null, dateAndTime);
messagesDatabaseReference.push().setValue(message);

如何将带有消息的时间戳发送到Android中的firebase数据库？

2 个答案: