Something like this should work. Note that for simplicity, I&#39;ve used a Java 7 feature (try block with closeable resource), and IOUtils from Apache commons-io. If you can&#39;t use those it&#39;ll be a little longer, but the same idea.

    import org.apache.commons.io.IOUtils;

    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;

    public class StreamUtil {

        public static final String PREFIX = &quot;stream2file&quot;;
        public static final String SUFFIX = &quot;.tmp&quot;;

        public static File stream2file (InputStream in) throws IOException {
            final File tempFile = File.createTempFile(PREFIX, SUFFIX);
            tempFile.deleteOnExit();
            try (FileOutputStream out = new FileOutputStream(tempFile)) {
                IOUtils.copy(in, out);
            }
            return tempFile;
        }

    }


You can&#39;t. The input stream is just a generic stream of data and there is no guarantee that it actually originates from a File. If someone created an InputStream from reading a web service or just converted a String into an InputStream, there would be no way to link this to a file. So the only thing you can do is actually write data from the stream to a temporary file (e.g. using the File.createTempFile method) and feed this file into your method. 

I have an ASP.NET website written in C#.

On this site I need to automatically show a start page based on the user&#39;s location.

Can I get name of user&#39;s city based on the IP address of the user ?

Get user location by IP address

I know it is a common issue, but looking for references and other material I don&#39;t find a clear answer to this question.

Consider the following code:

    #include &lt;string&gt;
    
    // ...
    // in a method
    std::string a = &quot;Hello &quot;;
    std::string b = &quot;World&quot;;
    std::string c = a + b;

The compiler tells me it cannot find an overloaded operator for `char[dim]`.

Does it mean that in the string there is not a + operator?

But in several examples there is a situation like this one. If this is not the correct way to concat more strings, what is the best way?

Concatenating strings doesn&#39;t work as expected

I have a method which expects the one of the input variable to be of java.io.File type but what I get is only InputStream. Also, I cannot change the signature of the method.

How can I convert the InputStream into File type with out actually writing the file on to the filesystem?

How to convert InputStream to virtual File

<p>I have a method which expects the one of the input variable to be of java.io.File type but what I get is only InputStream. Also, I cannot change the signature of the method.</p>
<p>How can I convert the InputStream into File type with out actually writing the file on to the filesystem?</p>


I can serialize a `List&lt;Video&gt;` in my servlet on GAE, but I can&#39;t deserialize it.  What am I doing wrong?

This is my class Video in GAE, which is serialized:

```
package legiontube;

import java.util.Date;

import javax.jdo.annotations.IdGeneratorStrategy;
import javax.jdo.annotations.IdentityType;
import javax.jdo.annotations.PersistenceCapable;
import javax.jdo.annotations.Persistent;
import javax.jdo.annotations.PrimaryKey;

@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class Video {
 
    @PrimaryKey
    private String id;
    
    @Persistent
    private String titulo;
    
    @Persistent
    private String descricao;
    
    @Persistent
    private Date date;

    public Video(){};
    
 public Video(String id, String titulo, String descricao, Date date) {
  //super();
  this.id = id;
  this.titulo = titulo;
  this.descricao = descricao;
  this.date = date;
 }

 public String getId() {
  return id;
 }

 public void setId(String id) {
  this.id = id;
 }

 public String getTitulo() {
  return titulo;
 }

 public void setTitulo(String titulo) {
  this.titulo = titulo;
 }

 public String getDescricao() {
  return descricao;
 }

 public void setDescricao(String descricao) {
  this.descricao = descricao;
 }

 public Date getDate() {
  return date;
 }

 public void setDate(Date date) {
  this.date = date;
 }
    
}
```

This is my class Video in my other application, where I try to deserialize:

```
package classes;

import java.util.Date;

public class Video {
 private String id;
 private String titulo;
 private String descricao;
 private Date date;
 
 public Video(String id, String titulo, String descricao, Date date) {
  //super();
  this.id = id;
  this.titulo = titulo;
  this.descricao = descricao;
  this.date = date;
 }
 
 public String getId() {
  return id;
 }
 public void setId(String id) {
  this.id = id;
 }
 public String getTitulo() {
  return titulo;
 }
 public void setTitulo(String titulo) {
  this.titulo = titulo;
 }
 public String getDescricao() {
  return descricao;
 }
 public void setDescricao(String descricao) {
  this.descricao = descricao;
 }
 public Date getDate() {
  return date;
 }
 public void setDate(Date date) {
  this.date = date;
 }
 
}
```

How to deserialize a list using GSON or another JSON library in Java?

I have code in my application that detects if Wi-Fi is actively connected. That code triggers a RuntimeException if airplane mode is enabled. I would like to display a separate error message when in this mode anyway. How can I reliably detect if an Android device is in airplane mode?


How can one detect airplane mode on Android?

How can I pass a primitive type by reference in java? For instance, how do I make an `int` passed to a method modifiable?

How do I pass a primitive data type by reference?

Is there a base-64 decoder and encoder for a String in Android?

Base64 encoder and decoder

I&#39;m trying to work with Hibernate in Eclipse.
I&#39;m creating a new simple project and I&#39;ve downloaded a collegue project too, via CVS.
Both don&#39;t work, while on my collegue&#39;s Eclipse do.
The problem is that, for each import of an Hibernate class, Eclipse says: 

    The import org.hibernate cannot be resolved

But all Hibernate jars are in the build path, that is:

    antlr-2.7.6.jar
    cglib-2.2.jar
    commons-collections-3.1.jar
    dom4j-1.6.1.jar
    hibernate3.jar
    hibernate-jpa-2.0-api-1.0.0.Final.jar
    javassist-3.12.0.GA.jar
    jta-1.1.jar
    slf4j-api-1.6.1.jar

Eclipse error: &quot;The import XXX cannot be resolved&quot;

I&#39;d like to restrict the type of file that can be chosen from the native OS file chooser when the user clicks the Browse button in the `&lt;input type=&quot;file&quot;&gt;` element in HTML. I have a feeling it&#39;s impossible, but I&#39;d like to know if there _is_ a solution. I&#39;d like to keep solely to HTML and JavaScript; no Flash please.

Limit file format when using &lt;input type=&quot;file&quot;&gt;?

I tried to commit multiple files across different directories in a single shot as below,

    svn commit –m”log msg” mydir/dir1/file1.c mydir/dir2/myfile1.h mydir/dir3/myfile3.c etc etc

Since, I wanted to exclude some files from the commit list so I’ve placed each file name in the command line as above. I put it together in the notepad and it came about 25 files.  When I copy and paste it on the command line, the last few files are missing and I guess this might be a command line buffer limitation (?). Is there any option I can increase the buffer length?

Is there any option I can put all files in a text file and give it as an argument to svn commit? 


SVN- How to commit multiple files in a single shot

With Java:

I have a `byte[]` that represents a file.

How do I write this to a file (ie. `C:\myfile.pdf`)



I know it&#39;s done with InputStream, but I can&#39;t seem to work it out.

byte[] to file in Java

What is the difference between Reader and InputStream?
And when to use what?
If I can use Reader for reading characters why I will use inputstream, I guess to read objects?

What is the difference between Reader and InputStream?

Is there a good way to read, edit, and write files in place in Ruby?

In my online search I&#39;ve found stuff suggesting to read it all into an array, modify said array, then write everything out. I feel like there should be a better solution, especially if I&#39;m dealing with a very big file.

Something like:

    myfile = File.open(&quot;path/to/file.txt&quot;, &quot;r+&quot;)

    myfile.each do |line|
        myfile.replace_puts(&#39;blah&#39;) if line =~ /myregex/
    end

    myfile.close

Where `replace_puts` would write over the current line, rather than (over)writing the next line as it currently does because the pointer is at the end of the line (after the separator).

So then every line that matches `/myregex/` will be replaced with &#39;blah&#39;. Obviously what I have in mind is a bit more involved than that, as far as processing, and would be done in one line, but the idea is the same - I want to read a file line by line, and edit certain lines, and write out when I&#39;m done.

Maybe there&#39;s a way to just say &quot;rewind back to just after the last separator&quot;? Or some way of using `each_with_index` and write via a line index number? I couldn&#39;t find anything of the sort, though.

The best solution I have so far is to read things line-wise, write them out to a new (temp) file line-wise (possibly edited), then overwrite the old file with the new temp file and delete. Again, I feel like there should be a better way - I don&#39;t think I should have to create a new 1gig file just to edit some lines in an existing 1GB file.


Read, edit, and write a text file line-wise using Ruby

I have a method that takes an InputStream and reads data from it. I would like to use this method with a ByteBuffer also. Is there a way to wrap a ByteBuffer so it can be accessed as a stream?

Wrapping a ByteBuffer with an InputStream

Why does [`InputStream#read()`][1] return an `int` and not a `byte`?


  [1]: http://docs.oracle.com/javase/6/docs/api/java/io/InputStream.html#read%28%29

Why does InputStream#read() return an int and not a byte?

Is there any way to check if InputStream has been gzipped?
Here&#39;s the code:

    public static InputStream decompressStream(InputStream input) {
		try {
			GZIPInputStream gs = new GZIPInputStream(input);
			return gs;
		} catch (IOException e) {
			logger.info(&quot;Input stream not in the GZIP format, using standard format&quot;);
			return input;
		}
	}

I tried this way but it doesn&#39;t work as expected - values read from the stream are invalid.
EDIT:
Added the method I use to compress data: 

    public static byte[] compress(byte[] content) {
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		try {
			GZIPOutputStream gs = new GZIPOutputStream(baos);
			gs.write(content);
			gs.close();
		} catch (IOException e) {
			logger.error(&quot;Fatal error occured while compressing data&quot;);
			throw new RuntimeException(e);
		}
		double ratio = (1.0f * content.length / baos.size());
		if (ratio &gt; 1) {
			logger.info(&quot;Compression ratio equals &quot; + ratio);
			return baos.toByteArray();
		}
		logger.info(&quot;Compression not needed&quot;);
		return content;

	}

Content Type	Original Author	Original Content on Stackoverflow
Question	Ram	View Question on Stackoverflow
Solution 1 - Java	cobbzilla	View Answer on Stackoverflow
Solution 2 - Java	Jan Thomä	View Answer on Stackoverflow

How to convert InputStream to virtual File

Java Problem Overview

Java Solutions

Solution 1 - Java

Solution 2 - Java

Concatenating strings doesn't work as expected

Get user location by IP address

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