Java字符串写入文件三种方式的实现

String str="hello world!";    FileWriter writer;    try {      writer = new FileWriter("E:/token.txt");      writer.write(str);      writer.flush();      writer.close();    } catch (IOException e) {      e.printStackTrace();    }

File txt=new File("E:/log1.txt");       if(!txt.exists()){          txt.createNewFile();       }        byte bytes[]=new byte[512];         bytes=str.getBytes();        int b=bytes.length;  //是字节的长度，不是字符串的长度       FileOutputStream fos=new FileOutputStream(txt);        fos.write(bytes,0,b);        fos.write(bytes);       fos.close();

FileOutputStream fos = new FileOutputStream("E:/log.txt",true);//true表示在文件末尾追加 fos.write(log.getBytes()); fos.close();