实用Java基础流计算

Posted 2021-03-22 为爱奋斗不息

java的流不常用，每次学习完都懂，过了一段时间就全忘了。。。

记录下一点实用的东西。。。

需求： 截取文件的前250kb内容

 

public static void main(String[] args) {
    read("data");
}

public static void read(String inputFileName)  {
    String root = "/Users/xxx/Desktop/data/";
    inputFileName = root + inputFileName ;

    String outputFileName = inputFileName + 250 + "kb.html";
    inputFileName = inputFileName + ".html";

    File input = null;
    File out = null;
    try {
        BufferedReader bufferedReader = new BufferedReader(new FileReader(inputFileName));

        out = new File(outputFileName);
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(out));

        String line = null;
        while((line = bufferedReader.readLine())!=null){
            long len = out.length();
            long max = 250 * 1024;
            if (len < max) {
                bufferedWriter.write(line);
                bufferedWriter.newLine();
                bufferedWriter.flush();
            }else {
                break;
            }
        }
        bufferedWriter.close();
        bufferedReader.close();
    }catch (Exception e){
        System.out.println(e.getMessage());
    }

}