Android Amazon DynamoDb基本操作中的错误 [英] Android Amazon DynamoDb error in basic action

问题描述

我正在尝试构建一个可以与Amazon DynamoDB交互的简单android应用。我已经下载了最新的Android Studio以及AWS移动SDK。我现在想要做的只是在表 customer中插入一行。但是，当我运行该应用程序时，遇到以下错误。如果你们能帮助我看看，如果我犯了一些愚蠢的错误，将不胜感激。（我已经按照文档设置了标识池，创建了新策略，将内容放入AsyncTask..etc）

I am trying to build a simple android app that can interact with Amazon DynamoDB. I have download the latest Android Studio and also AWS mobile SDK. What I am trying to do now is simply insert a row into my table "customer". However when I run the app I encounter the following error. Would really appreciate if you guys can help me take a look and sorry if I make some stupid mistakes.(I have follow the doc to set up identification pool, create new policy, put stuff in AsyncTask..etc)

谢谢

An

错误

07-21 23:31:59.781    4207-4234/com.example.an.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
Process: com.example.an.myapplication, PID: 4207
java.lang.RuntimeException: An error occured while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:304)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
        at java.util.concurrent.FutureTask.run(FutureTask.java:242)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:818)
 Caused by: com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper.DynamoDBMappingException: No interface com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper.DynamoDBHashKey annotation found in class class com.example.an.myapplication.customers
        at com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper.DynamoDBMapper.needAutoGenerateAssignableKey(DynamoDBMapper.java:720)
        at com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper.DynamoDBMapper.save(DynamoDBMapper.java:780)
        at com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper.DynamoDBMapper.save(DynamoDBMapper.java:688)
        at com.example.an.myapplication.MainActivity$db.doInBackground(MainActivity.java:67)
        at com.example.an.myapplication.MainActivity$db.doInBackground(MainActivity.java:56)
        at android.os.AsyncTask$2.call(AsyncTask.java:292)
        at java.util.concurrent.FutureTask.run(FutureTask.java:237)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:818)

MainActivity.java

package com.example.an.myapplication;
import android.content.Context;
import android.os.AsyncTask;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import com.amazonaws.auth.CognitoCachingCredentialsProvider;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.dynamodbv2.*;
import com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper.*;



public class MainActivity extends ActionBarActivity {
private CognitoCachingCredentialsProvider credentialsProvider;
private static final String TAG = MainActivity.class.getSimpleName();


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    credentialsProvider = new CognitoCachingCredentialsProvider(
            this.getApplicationContext(),    /* get the context for the current activity */
            "us-east-1:ef8bfc69-88b7-4714-ae0a-223f08a20fe5", // Identity Pool ID
            Regions.US_EAST_1 // Region
    );
    new db().execute("");
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

private class db extends AsyncTask<String, Void, String> {
    @Override
    protected String doInBackground(String... params) {

        AmazonDynamoDBClient ddbClient = new AmazonDynamoDBClient(credentialsProvider);
        DynamoDBMapper mapper = new DynamoDBMapper(ddbClient);
        customers customer = new customers();
        customer.setCustomerID("GG");
        customer.setBalance(5);
        mapper.save(customer);
        return "Executed";
    }

    @Override
    protected void onPostExecute(String result) {}

    @Override
    protected void onPreExecute() {}

    @Override
    protected void onProgressUpdate(Void... values) {}
}
}

customer.java

package com.example.an.myapplication;
import com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper.*;


@DynamoDBTable(tableName = "customer")
public class customers {
private String id;
private int balance;

@DynamoDBIndexHashKey(attributeName = "CustomerID")
public String getCustomerID() {
    return id;
}

public void setCustomerID(String id) {
    this.id = id;
}

@DynamoDBAttribute(attributeName = "Balance")
public int getBalance() {
    return balance;
}

public void setBalance(int balance) {
    this.balance = balance;
}
}

推荐答案

I最后在Amazon支持的帮助下解决该问题。

I finally fix the problem with the help of Amazon support

In customers.java, you don't have an attribute annotated with DynamoDBHashKey.
Not sure how your DynamoDB table is set up. At minimum, it needs a hash key.
If CustomerID is the hash key, then you need to change of the annotation of id
from DynamoDBIndexHashKey to DynamoDBHashKey.

所以事实证明，我使用@DynamoDBIndexHashKey而不是@DynamoDBHashKey！更正它后就可以了！

So it turn out I use @DynamoDBIndexHashKey instead of @DynamoDBHashKey! After correcting that it works!

这篇关于Android Amazon DynamoDb基本操作中的错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！