Question

String time=Read_one_Line();

public static String Read_one_Line() throws FileNotFoundException, IOException
{

  FileInputStream fin=new FileInputStream("sample.txt");

  BufferedReader br=new BufferedReader(new InputStreamReader(fin));

  str=br.readLine();

  next_line=br.readLine();

  return next_line;
}

每次应从文本文件中读取一行，名为＆＃34; sample.txt＆＃34; ，返回。下次它应该返回下一行等等......

sample.txt的内容为：

Date:0   Year:0  Hour:0  Minute:0    Seconds:0   MilliSeconds:310

Date:0   Year:0  Hour:0  Minute:0    Seconds:0   MilliSeconds:0

Date:0   Year:0  Hour:0  Minute:0    Seconds:0   MilliSeconds:10

Date:0   Year:0  Hour:0  Minute:0    Seconds:0   MilliSeconds:0

Date:0   Year:0  Hour:0  Minute:0    Seconds:0   MilliSeconds:380

Date:0   Year:0  Hour:0  Minute:0    Seconds:10  MilliSeconds:-840

Date:0   Year:0  Hour:0  Minute:0    Seconds:0   MilliSeconds:0

Date:0   Year:0  Hour:0  Minute:0    Seconds:0   MilliSeconds:0

Date:0   Year:0  Hour:0  Minute:0    Seconds:0   MilliSeconds:0

Date:0   Year:0  Hour:0  Minute:0    Seconds:0   MilliSeconds:0

而是每次只读它并返回第一行..请告诉我如何递增到下一行并在下次调用此函数时返回它。

Answer 1

每次调用函数时，您都在创建一个新的FileInputStream。因此，每次都从头开始读取文件。

在函数外部只创建BufferedReader一次，并在每次调用时传入它，以便连续读取该文件。

public static String Read_one_Line(final BufferedReader br) throws IOException
{
  next_line=br.readLine();

  return next_line;
}

用法就像

static void main(String args[]) throws IOException {

  FileInputStream fin=new FileInputStream("sample.txt");

  try {

    BufferedReader br=new BufferedReader(new InputStreamReader(fin));

    String line = Read_one_Line(br);
    while ( line != null ) {
      System.out.println(line);
      line = Read_one_Line(br);
    }

  } finally {
    fin.close(); // Make sure we close the file when we're done.
  }
}

请注意，在这种情况下，Read_one_Line可以省略，并替换为简单的br.readLine()。

如果你只想要每隔一行，你可以在每次迭代中读取两行，比如

String line = Read_one_Line(br);
while ( line != null ) {
  System.out.println(line);
  String dummy = Read_one_Line(br);
  line = Read_one_Line(br);
}

每次调用函数时，从文件中读取一行

1 个答案: