How to create a temp file in java without the random number appended to the filename?
JavaTemporary FilesJava Problem Overview
I need to create a temp file, so I tried this:
String[] TempFiles = {"c1234c10","c1234c11","c1234c12","c1234c13"};
for (int i = 0; i <= 3; i++) {
try {
String tempFile = TempFiles[i];
File temp = File.createTempFile(tempFile, ".xls");
System.out.println("Temp file : " + temp.getAbsolutePath());
} catch (IOException e) {
e.printStackTrace();
}
}
The output is something like this:
Temp file : C:\Users\MD1000\AppData\Local\Temp\c1234c108415816200650069233.xls
Temp file : C:\Users\MD1000\AppData\Local\Temp\c1234c113748833645638701089.xls
Temp file : C:\Users\MD1000\AppData\Local\Temp\c1234c126104766829220422260.xls
Temp file : C:\Users\MD1000\AppData\Local\Temp\c1234c137493179265536640669.xls
Now, I don't want the extra numbers (long int) which is getting added to the file name. How can I achieve that? Thanks
Java Solutions
Solution 1 - Java
First, use the following snippet to get the system's temp directory:
String tDir = System.getProperty("java.io.tmpdir");
Then use the tDir
variable in conjunction with your tempFiles[]
array to create each file individually.
Solution 2 - Java
Using [Guava][1]:
import com.google.common.io.Files;
...
File myTempFile = new File(Files.createTempDir(), "MySpecificName.png");
[1]: https://github.com/google/guava "Guava"
Solution 3 - Java
You can't if you use File.createTempFile
to generate a temporary file name. I looked at the java source for generating a temp file (for java 1.7, you didn't state your version so I just used mine):
private static class TempDirectory {
private TempDirectory() { }
// temporary directory location
private static final File tmpdir = new File(fs.normalize(AccessController
.doPrivileged(new GetPropertyAction("java.io.tmpdir"))));
static File location() {
return tmpdir;
}
// file name generation
private static final SecureRandom random = new SecureRandom();
static File generateFile(String prefix, String suffix, File dir) {
long n = random.nextLong();
if (n == Long.MIN_VALUE) {
n = 0; // corner case
} else {
n = Math.abs(n);
}
return new File(dir, prefix + Long.toString(n) + suffix);
}
}
This is the code in the java JDK that generates the temp file name. You can see that it generates a random number and inserts it into your file name between your prefix and suffix. This is in "File.java" (in java.io). I did not see any way to change that.
Solution 4 - Java
If you want files with specific names created in the system-wide temporary directory, then expand the %temp%
environment variable and create the file manually, nothing wrong with that.
Edit: Actually, use System.getProperty("java.io.tmpdir"));
for that.
Solution 5 - Java
You can create a temp directory then store new files in it. This way all of the new files you add won't have a random extension to it. When you're done all you have to do is delete the temp directory you added.
public static File createTempFile(String prefix, String suffix) {
File parent = new File(System.getProperty("java.io.tmpdir"));
File temp = new File(parent, prefix + suffix);
if (temp.exists()) {
temp.delete();
}
try {
temp.createNewFile();
} catch (IOException ex) {
ex.printStackTrace();
}
return temp;
}
public static File createTempDirectory(String fileName) {
File parent = new File(System.getProperty("java.io.tmpdir"));
File temp = new File(parent, fileName);
if (temp.exists()) {
temp.delete();
}
temp.mkdir();
return temp;
}
Solution 6 - Java
Just putting up the option here: If someone anyhow need to use createTempFile method, you can do create a temp file and rename it using Files.move option:
final Path path = Files.createTempFile(fileName, ".xls");
Files.move(path, path.resolveSibling(fileName));
Solution 7 - Java
Custom names can be saved as follows
File temp=new File(tempFile, ".xls");
if (!temp.exists()) {
temp.createNewFile();
}
Solution 8 - Java
public static File createTempDirectory(String dirName) {
File baseDir = new File(System.getProperty("java.io.tmpdir"));
File tempDir = new File(baseDir, dirName);
if (tempDir.mkdir()) {
return tempDir;
}
return null;
}