Cannot resolve symbol 'IOUtils'

问题:

I have used the following code to create a temporary file in my android app:

public File streamToFile (InputStream in) throws IOException {
    File tempFile = File.createTempFile("sample", ".tmp");
    tempFile.deleteOnExit();
    FileOutputStream out = new FileOutputStream(tempFile);
    IOUtils.copy(in, out);
    return tempFile;
}

Now the problem is Cannot resolve symbol 'IOUtils'. I did a little bit of googling and discovered that for using IOUtils I need to download and include a jar file. I downloaded the jar file from here(commons-io-2.4-bin.zip). I added the jar named commons-io-2.4.jar from the zip to my bundle and when I tried to import it using:

import org.apache.commons.io.IOUtils;

It is showing error Cannot resolve symbol 'io'. So I tried to import it like:

import org.apache.commons.*

But still I am getting the error Cannot resolve symbol 'IOUtils'.

Question 1 : Why am I getting this error? How to resolve it?

Question 2 : Is there any way to create a temp file from an InputStream without using an external library? Or is this the most efficient way to do that? I am using android studio.

回答1:

For Android Studio:

1. File -> Project Structure... -> Dependencies
2. Click '+' in the upper right corner and select "Library dependency"
3. In the search field type: "org.apache.commons.io" and click Search
4. Select "org.apache.directory.studio:org.apache.commons.io:

Happy coding :)

回答2:

Right clicking on the commons-io-2.4.jar file in project navigator and clicking 'Add to project' solved the issue.

回答3:

For those who encountered this while working on a Netbeans Java project. What I did is I downloaded the Binaries Zip of IO here

Commons IO Util Jar Download Here

Then Right clicked on my Project>Properties>

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On the Categories Pane, Click Libraries

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Then Click Add Jar/Folder

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Locate the jar file/folder of the extracted IO Util that was downloaded.

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Then click Ok. That fixed mine. :)