Java自动生成目录（如果存在） [英] Java autogenerate directories if exists

问题描述

我正在尝试检查目录是否存在，如果发生这种情况我想给它另一个数字，例如，如果存在folderX我想创建一个名为FolderX1的新目录，此刻我我只能这样做一次，因为我在if / else语句中这样做：

I'm trying to check if a directory exists, if that happens I want to give it another number, for example, if "folderX" exists I want to create a new one called "FolderX1", at the moment I'm just able to do this once since I have it on an if/else statement like this:

    File fa = new File(folder);

    if(!fa.exists()){
        this.folder = folder;
    }else{
        this.folder = folder+=1;

     }

我想以递归方式执行此操作，如果程序检测到 folderX存在它应该跳转并检查其他人（folderX，FolderX1，FolderX2等），直到找到一个可以创建但我不知道如何做的。

I want do this recursively, If the program detects that "folderX" exists it should jump and check the others (folderX,FolderX1,FolderX2, etc) until it finds one that can be created but i don't know how to do it.

推荐答案

基本上，您需要某种循环来确定递增文件夹是否仍然存在...

Basically, you need some kind of loop that can determine if the incrementing folder still exists...

File makeMe = new File(folder);
int index = 0;
String master = folder;
while (makeMe.exists()) {
    folder = master + (++index);
    makeMe = new File(folder);
}

如果您担心创建无限循环，可以放置最大值范围......

If you're worried about creating an infinite loop, you could place a maximum range...

int maxRange = 100;

File makeMe = new File(folder);
int index = 0;
String master = folder;
while (makeMe.exists() && index < maxRange) {
    makeMe = new File(master + (++index));
}

if (index > maxRange) { // || makeMe.exists()
    throw new IOException("Could not find free directory");
} else {
    // All happy unicorns...
}

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