day18/day18_IO/FileWriterDemo2.java

/*演示对已有文件的数据续写。*/import java.io.*;class FileWriterDemo2 {public static void main(String[] args) {FileWriter fw = null;try{//传递一个true参数，代表不覆盖已有的文件。并在已有文件的末尾处进行数据续写。fw = new FileWriter("demo.txt",true);//fw.write("nihao\r\nxiexie");//linux系统可以识别 \n 就是换行，而windows系统要加上\r\n才能是换行}catch (IOException e){System.out.println(e.toString());}finally{try{if(fw!=null)fw.close();}catch (IOException e){System.out.println(e.toString());}}}}