try(管道流、連接等實(shí)現(xiàn)了Closeable接口的類(lèi)){
  //這里使用類(lèi)對(duì)象操作
}
//用try()包含起來(lái)，就不用在finally里面自己手動(dòng)的去 Object.close()了，會(huì)自動(dòng)的關(guān)閉

@Test
void testCreateFile1() throws IOException {
  String fileName = "D:\\data\\test\\newFile.txt";

  Path path = Paths.get(fileName);
  // 使用newBufferedWriter創(chuàng)建文件并寫(xiě)文件
  // 這里使用了try-with-resources方法來(lái)關(guān)閉流，不用手動(dòng)關(guān)閉
  try (BufferedWriter writer =
          Files.newBufferedWriter(path, StandardCharsets.UTF_8)) {
   writer.write("Hello World -創(chuàng)建文件!!");
  }

  //追加寫(xiě)模式
  try (BufferedWriter writer =
        Files.newBufferedWriter(path,
            StandardCharsets.UTF_8,
            StandardOpenOption.APPEND)){
    writer.write("Hello World -字母哥!!");
  }
}

@Test
void testCreateFile2() throws IOException {
  String fileName = "D:\\data\\test\\newFile2.txt";

  // 從JDK1.7開(kāi)始提供的方法
  // 使用Files.write創(chuàng)建一個(gè)文件并寫(xiě)入
  Files.write(Paths.get(fileName),
        "Hello World -創(chuàng)建文件!!".getBytes(StandardCharsets.UTF_8));

  // 追加寫(xiě)模式
  Files.write(
     Paths.get(fileName),
     "Hello World -字母哥!!".getBytes(StandardCharsets.UTF_8),
     StandardOpenOption.APPEND);
}

@Test
void testCreateFile3() throws IOException {
  String fileName = "D:\\data\\test\\newFile3.txt";

  // JSD 1.5開(kāi)始就已經(jīng)存在的方法
  try (PrintWriter writer = new PrintWriter(fileName, "UTF-8")) {
   writer.println("Hello World -創(chuàng)建文件!!");
   writer.println("Hello World -字母哥!!");
  }

  // Java 10進(jìn)行了改進(jìn)，支持使用StandardCharsets指定字符集
  /*try (PrintWriter writer = new PrintWriter(fileName, StandardCharsets.UTF_8)) {

   writer.println("first line!");
   writer.println("second line!");

  } */

}

@Test
void testCreateFile4() throws IOException {
  String fileName = "D:\\data\\test\\newFile4.txt";

  File file = new File(fileName);

  // 返回true表示文件成功
  // false 表示文件已經(jīng)存在
  if (file.createNewFile()) {
   System.out.println("創(chuàng)建文件成功！");
  } else {
   System.out.println("文件已經(jīng)存在不需要重復(fù)創(chuàng)建");
  }

  // 使用FileWriter寫(xiě)文件
  try (FileWriter writer = new FileWriter(file)) {
   writer.write("Hello World -創(chuàng)建文件!!");
  }

}

@Test
void testCreateFile5() throws IOException {
  String fileName = "D:\\data\\test\\newFile5.txt";
  try(FileOutputStream fos = new FileOutputStream(fileName);
   OutputStreamWriter osw = new OutputStreamWriter(fos);
   BufferedWriter bw = new BufferedWriter(osw);){
   bw.write("Hello World -創(chuàng)建文件!!");
   bw.flush();
  }
}