如何在Java中的项目文件夹中创建文件？

Question

in JsonOperation class:

public void writeJson(String path, JSONObject passedJsonObj){
    File file = new File(path);
    try{
        if (!file.exists()){
            file.createNewFile();
        }
        FileWriter writer = new FileWriter(file);
        writer.write(passedJsonObj.toJSONString());
        writer.flush();
        writer.close();
    }catch(IOException e){
        e.printStackTrace();
    }
}

in my main calling class:

    LocalDate todayDate = LocalDate.now();
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MM/yyyy");
    String dateString = todayDate.format(formatter).toString();

    JsonOperation jsonOp = new JsonOperation();
    jsonOp.writeJson("srcsample/SaveData.json", jsonOp.toJsonObj("dateToday", dateString) );

While running this, I got these errors:

java.io.IOException: The system cannot find the path specified
    at java.io.WinNTFileSystem.createFileExclusively(Native Method)
    at java.io.File.createNewFile(File.java:1012)
    at sample.JsonOperation.writeJson(JsonOperation.java:50)
    at sample.Main.saveData(Main.java:58)
    at sample.Main.start(Main.java:29)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$159(LauncherImpl.java:863)
    at com.sun.javafx.application.LauncherImpl$$Lambda$52/384953125.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$172(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl$$Lambda$48/113087735.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl.lambda$null$170(PlatformImpl.java:295)
    at com.sun.javafx.application.PlatformImpl$$Lambda$50/949297714.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$171(PlatformImpl.java:294)
    at com.sun.javafx.application.PlatformImpl$$Lambda$49/59984698.run(Unknown Source)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$145(WinApplication.java:101)
    at com.sun.glass.ui.win.WinApplication$$Lambda$38/665838427.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:745)

When I change

jsonOp.writeJson("\\src\\sample\\SaveData.json", jsonOp.toJsonObj("dateToday", dateString) );

into

jsonOp.writeJson("SaveData.json", jsonOp.toJsonObj("dateToday", dateString) );

it doesn't give me any error but it creates the file outside the src folder. What should I do to create the file inside sample folder?

My project heirarchy: WordToday>src>sample

Answer 1

In my project i created a "logs" folder outside the src folder with the file definition:

File file = new File("logs/file.txt");

So I expect you can create a file there with File("/file.txt")

Answer 2

Try using the asbolute path. When you use the relative path, the file is not being created inside the folder you think it is.

You can try the following to check where your relative path is:

Path currentRelativePath = Paths.get("");
String s = currentRelativePath.toAbsolutePath().toString();
System.out.println("Current relative path is: " + s);

Try it and let me know.

EDIT: See this for more information: http://docs.oracle.com/javase/tutorial/essential/io/pathOps.html

Answer 3

1. For creating in any folder

   File file = new File("C:\\\\Users\\\\YourUserName\\\\Directory\\\\fileName.txt");

2. For in Project directory

   File = new File("directory/fileName.txt");

3. Check if file exists, if not create new

   if (!file.exists()) { file.createNewFile(); }