Java 系统找不到 FileWriter 指定的路径
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The system cannot find the path specified with FileWriter
提问by rfgamaral
I have this code:
我有这个代码：
private static void saveMetricsToCSV(String fileName, double[] metrics) {
try {
FileWriter fWriter = new FileWriter(
System.getProperty("user.dir") + "\output\" +
fileTimestamp + "_" + fileDBSize + "-" + fileName + ".csv"
);
BufferedWriter csvFile = new BufferedWriter(fWriter);
for(int i = 0; i < 4; i++) {
for(int j = 0; j < 5; j++) {
csvFile.write(String.format("%,10f;", metrics[i+j]));
}
csvFile.write(System.getProperty("line.separator"));
}
csvFile.close();
} catch(IOException e) {
System.out.println(e.getMessage());
}
}
But I get this error:
但我收到此错误：
C:\Users\Nazgulled\Documents\Workspace\Só Amigos\output\1274715228419_5000-List-ImportDatabase.csv (The system cannot find the path specified)
C:\Users\Nazgulled\Documents\Workspace\Só Amigos\output\1274715228419_5000-List-ImportDatabase.csv（系统找不到指定的路径）
Any idea why?
知道为什么吗？
I'm using NetBeans on Windows 7 if it matters...
如果重要的话，我在 Windows 7 上使用 NetBeans...
采纳答案by leonbloy
In general, a non existent file will be created by Java only if the parent directory exists. You should check/create the directory tree:
通常，只有父目录存在，Java 才会创建不存在的文件。您应该检查/创建目录树：
String filenameFullNoPath = fileTimestamp + "_" + fileDBSize + "-"
+ fileName + ".csv";
File myFile = new File(System.getProperty("user.dir") + File.separator
+ "output" + File.separator + filenameFullNoPath);
File parentDir = myFile.getParentFile();
if(! parentDir.exists())
parentDir.mkdirs(); // create parent dir and ancestors if necessary
// FileWriter does not allow to specify charset, better use this:
Writer w = new OutputStreamWriter(new FileOutputStream(myFile),charset);
回答by Brett Kail
I'd guess that the "output" directory doesn't exist. Try adding:
我猜想“输出”目录不存在。尝试添加：
new File(System.getProperty("user.dir") + File.separator + "output").mkdir();
回答by ems
You can use getParentFile(Java Doc) to make sure that the parent directory exists. The following will check that the parent directory exists, and create it if it doesn't.
您可以使用getParentFile( Java Doc) 来确保父目录存在。下面将检查父目录是否存在，如果不存在则创建它。
File myFile = new File(fileName);
if(!myFile.getParentFile.exists()) {
myFile.getParentFile.mkdirs();
}
