@Test

public void test3(){

    File file = new File("hello1.txt");

    FileWriter fw = null;

    try {

        //自动创建文件。默认false，覆盖写；true追加写

        fw = new FileWriter(file, true);

        fw.write("天南地北");

    } catch (IOException e) {

        e.printStackTrace();

    }finally {

        if (fw != null){

            try {

                fw.close();

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

    }

}