## java存储数据到本地txt文件中 以下测试类是生成200万条十二位随机数 ``` @Test public void generateCode() { long start = System.currentTimeMillis(); //随机生成激活码 int sum = 2000000; try { File file = new File("D:\\data.txt"); if(!file.exists()) { file.createNewFile(); // 创建新文件,有同名的文件的话直接覆盖 } FileOutputStream fos = new FileOutputStream(file,true); OutputStreamWriter osw = new OutputStreamWriter(fos); BufferedWriter bw = new BufferedWriter(osw); for (int i = 0;i<sum;i++) { String code = String.valueOf((long) (Math.random() * (999999999999l - 100000000000l)) + 100000000000l); bw.write(code); bw.newLine(); } bw.flush(); bw.close(); osw.close(); fos.close(); }catch (FileNotFoundException e1) { e1.printStackTrace(); } catch (IOException e2) { e2.printStackTrace(); } long end = System.currentTimeMillis(); System.out.println(end-start); } ```