链接：https://www.iteye.com/blog/nbh219-1865476

（侵删）

/**
* @param args
*/
public static void main(String s[]) {
try {
String url = "F:\\gsm\\";
String FileName = "info.dat";
File file = new File(url);
file.mkdirs();//创建文件夹
File fil = new File(url);
fil.createNewFile();
 
 
FileWriter fileWriter=new FileWriter(url+FileName);
fileWriter.write("gsmc");//写入文件
fileWriter.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

方法：

public void writeFile(String result) { 
        try { 
                String fileName = "C:/data/Data.dat";
                File file = new File(fileName);
                File fileParent = file.getParentFile();
                if(!fileParent.exists()){
                    fileParent.mkdirs();
                    }
                file.createNewFile();
//               false:覆盖之前写的  如果是true则为追加
                BufferedWriter writer = new BufferedWriter (new OutputStreamWriter (new FileOutputStream (file,false),"UTF-8"));
                writer.write(result);
                writer.flush();
                writer.close();
            } catch (IOException e) {
                e.printStackTrace(); 
        } 
    }