文件的读写

读数据：

public static String txt2String(){
        File file = new File("G:/data/swf/data.txt");
        StringBuilder result = new StringBuilder();
        try{
            InputStreamReader isr = new InputStreamReader(new FileInputStream(file), "UTF-8");
            BufferedReader br = new BufferedReader(isr);//构造一个BufferedReader类来读取文件
            String s = null;
            while((s = br.readLine())!=null){//使用readLine方法，一次读一行
                result.append(System.lineSeparator()+s);
            }
            br.close();
        }catch(Exception e){
            e.printStackTrace();
        }
        return result.toString();
    }

写入数据：

public static void writeFile(String str) throws IOException {
        //写入中文字符时解决中文乱码问题
        FileOutputStream fos=new FileOutputStream(new File("G:/data/swf/data.txt"),true);
        OutputStreamWriter osw=new OutputStreamWriter(fos, "UTF-8");
        BufferedWriter  bw=new BufferedWriter(osw);
        bw.write(str+",");

        //注意关闭的先后顺序，先打开的后关闭，后打开的先关闭
        bw.close();
        osw.close();
        fos.close();
    }