5 ways To resolve Java exclusive write files _java

This article illustrates the 5 ways to solve Java exclusive writing files, including some of their own understanding, if there is no place to welcome the proposed.

Scenario 1: Use the randomaccessfile file action option S,s to represent the synchronous lock mode write

Randomaccessfile file = new Randomaccessfile (file, "RWS");

Scenario 2: using the filechannel file lock

File File = new file ("Test.txt");
FileInputStream fis = new FileInputStream (file);
FileChannel channel = Fis.getchannel ();
Filelock filelock = null;
while (true) {
  Filelock = channel.trylock (0, Long.max_value, false);//True means shared lock, false is exclusive lock
  if (filelock!= NULL) break;
  else  //There are other threads occupying lock sleep
   (1000);
}

Scenario 3: write the content first to a temporary file, and then rename the temporary file (hack scheme, using the principle of buffering + Atomic operation)

public class MyFile {
  private String fileName;
  Public MyFile (String fileName) {
   this.filename = filename;
  }
 
  Public synchronized void WriteData (string data) throws IOException {
   string tmpfilename = Uuid.randomuuid (). toString () + ". tmp";
   File Tmpfile = new file (tmpfilename);
   FileWriter FW = new FileWriter (tmpfile);
   Fw.write (data);
   Fw.flush ();
   Fw.close ();
 
   Now rename temp file to desired name, this operation is atomic operation under most OS
   if (!tmpfile.renameto Me) {
     //We may want to retry if move fails
     throw new IOException (' Move failed ');
   }
  }

Scenario 4: encapsulating files based on file paths and using synchronized to control write files

public class MyFile {
  private String fileName;
  Public MyFile (String fileName) {
   this.filename = filename;
  } 
  Public synchronized void WriteData (String data) throws IOException {
   FileWriter fw = new FileWriter (fileName);
   Fw.write (data);
   Fw.flush ();
   Fw.close ();
  }     

Scenario 5: I think of a scheme that is not very precise. By switching settings read and Write permission control, the simulation set a writable mark (into the operating system of classic Read and write problems ...). ）

public class MyFile {
  private volatile Boolean canwrite = true;
  Private String fileName;
  Public MyFile (String fileName) {
   this.filename = filename;
  }
  public void WriteData (String data) {while
   (!canwrite) {
     try {thread.sleep ()} catch (Interuptedexception IE) {}//can set a timeout write time
   }
   canwrite = false;
    
   Now write file
 
   canwrite = true;
  }

The above is the Java exclusive write file solution, we have no learn, you can refer to other articles to learn understanding.