java一行一行读入数据

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException ;
public class txt {


    public static void readFileByLines(String fileName) {
        File file = new File(fileName);
        BufferedReader reader = null;
        try {
            System.out.println("以行为单位读取文件内容，一次读一行");
            reader = new BufferedReader(new FileReader(file));
            String tempString = null;
            int line = 1;
//一次读一行，读入null时文件结束
            while ((tempString = reader.readLine()) != null) {
//把当前行号显示出来
                System.out.println("line " + line + ": " + tempString);
                line++;
            }
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e1) {
                }
            }
        }
    }

    public static void main(String argv[]) {
        String filePath = "f:TOTAL.txt";
        readFileByLines(filePath);
    }
}