Java 创建文件前，删除前一天的文件
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Before creating the file , deleting the file of previous day
提问by Kishan Kumar
I am creating a dat file in C: drive folder named abc as shown below , Now my file is generated everyday now suppose if my file is generated today, then tommrow it will be also generated as usual but when tommrow it is generated I have to make sure that earlier day file is deleted as the space in that folder is limited and this check is every time need to be done previos day file to be get deleted from that folder , please advise how to achieve this..
我正在 C: 驱动器文件夹中创建一个名为 abc 的 dat 文件，如下所示，现在我的文件每天都会生成，现在假设我的文件是今天生成的，那么 tommrow 它将照常生成但是当 tommrow 生成时我必须确保删除较早的文件，因为该文件夹中的空间有限，并且每次需要完成此检查才能从该文件夹中删除前一天的文件，请告知如何实现此目的..
File file = new File(FilePath + getFileName()); //filepath is being passes through //ioc //and filename through a method
if (!file.exists()) {
file.createNewFile();
}
FileOutputStream fileOutput = new FileOutputStream(
file);
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(
fileOutput));
回答by Ashwani
If you are using Java 7 then there is standard way to get file creation time, So that you can check if file is created in previous day and should be delete.
如果您使用的是 Java 7，那么有标准的方法来获取文件创建时间，以便您可以检查文件是否在前一天创建并且应该删除。
Path path = Paths.get("/filepath/");
BasicFileAttributes fileAttributes = Files.readAttributes(path, BasicFileAttributes.class);
System.out.println("creationTime:"+ fileAttributes.creationTime());
回答by Alex
why not use file.delete()?
为什么不使用file.delete()？
File file = new File(FilePath + getFileName()); //filepath is being passes through //ioc //and filename through a method
if (file.exists()) {
file.delete(); //you might want to check if delete was successfull
}
file.createNewFile();
FileOutputStream fileOutput = new FileOutputStream(file);
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fileOutput));
回答by Ruchira Gayan Ranaweera
If your file name same in time to time no need to delete that. By running your code tomorrow, will over write file created today.
如果您的文件名不时相同，则无需删除该文件。通过明天运行您的代码，将覆盖今天创建的文件。
Consider following case
考虑以下情况
BufferedWriter bw=new BufferedWriter(new FileWriter("D:\Test\test.txt"));
bw.write("abbbb");
bw.close(); // now this will create a test.txt in side Test folder
now run this by change writing String
现在通过更改写入字符串来运行它
BufferedWriter bw=new BufferedWriter(new FileWriter("D:\test.txt"));
bw.write("hihi");
bw.close(); // now you can see file only containing hihi
回答by Saeed
You can change your code this way:
您可以通过以下方式更改代码：
if (file.exists()) {
file.delete();
}
file.createNewFile();
And if it does not work, it's a matter of permission.
如果它不起作用，那就是许可问题。
