public static String read(String filename) throws IOException
    {
        StringBuffer sb=new StringBuffer();
        BufferedReader in=new BufferedReader(new FileReader(filename));
        String s;
        while((s=in.readLine())!=null)
        {
            sb.append(s);
            sb.append("\n");
        }
        in.close();
        return sb.toString();
     }    public static void write(String filename,String text) throws IOException
    {
        
        PrintWriter out=new PrintWriter(new BufferedWriter(new FileWriter(filename)));
            
        out.write(text);
 out.close();
    } 
main()函数
String file=read("c:\\111.txt");
        System.out.print(file);
        write("c:\\1112222.txt",file);我在111.txt里面有换行的文本
然后通过print打印出来是有换行
但为什么写入文件111222里面换行就没了