Question

我在尝试读取资源文件夹中的文件时出现问题。有问题的图书馆是; Web3j的钱包实用程序类。由于某种原因，它不会找到json文件。 json文件位于assets文件夹中。

currentWallet = WalletUtils.loadCredentials(password , "/some.json");

堆栈跟踪如下;

W/Java7Support: Unable to load JDK7 types (annotations, java.nio.file.Path): no Java7 support added
E/Main Activity: onCreate: 
                 java.io.FileNotFoundException: keystore.json (No such file or directory)
                     at java.io.FileInputStream.open(Native Method)
                     at java.io.FileInputStream.<init>(FileInputStream.java:146)
                     at com.fasterxml.jackson.core.JsonFactory.createParser(JsonFactory.java:756)
                     at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2740)
                     at org.web3j.crypto.WalletUtils.loadCredentials(WalletUtils.java:81)
                     at org.web3j.crypto.WalletUtils.loadCredentials(WalletUtils.java:76)
                     at mecreative.studio.liberaltoken.MainActivity.handleCreateContract(MainActivity.java:126)
                     at java.lang.reflect.Method.invoke(Native Method)
                     at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
                     at android.view.View.performClick(View.java:6199)
                     at android.widget.TextView.performClick(TextView.java:11090)
                     at android.view.View$PerformClick.run(View.java:23647)
                     at android.os.Handler.handleCallback(Handler.java:751)
                     at android.os.Handler.dispatchMessage(Handler.java:95)
                     at android.os.Looper.loop(Looper.java:154)
                     at android.app.ActivityThread.main(ActivityThread.java:6682)
                     at java.lang.reflect.Method.invoke(Native Method)
                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1520)
                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1410)

我想明确说明，方法Wallet #loadCredentials接受一个字符串，后跟File对象或String对象。我试过了两个，他们都给出了同样的错误。

Answer 1

private BufferedReader file = new BufferedReader(new InputStreamReader(getAssets().open("file.json")));

Answer 2

 public static String getJSONFileFromAsset(String filename, Context context) throws IOException {
    AssetManager manager = context.getAssets();
    InputStream file = manager.open(filename);
    byte[] formArray = new byte[file.available()];
    file.read(formArray);
    file.close();
    return new String(formArray);
}

这应该有效

Answer 3

从文件中读取数据的其他选项

public String ReadDataFromFile(String file) {
    String data = "";

try {
    InputStream stream = getAssets().open(file);

    int size = stream.available();
    byte[] buffer = new byte[size];
    stream.read(buffer);
    stream.close();
    data = new String(buffer);
} catch (IOException e) {
    // Handle exceptions here
}

return data;
}

并使用

 String yourData = ReadDataFromFile("YourDataFile.json");

为什么我不能从我的资产文件夹中读取文件？

3 个答案: