Question

我正在尝试从dat文件中打印特定数据，在这种情况下，此文件包含多部电影中的数据。我将如何仅打印id和title列的数据？

movie.dat文件的内容

id  title       imdbID      SpanishTitle
1   Toy story   0114709     juguetes
2   Jumanji     0113497     jumanji
3   Grumpy Old Men  0107050     Dos viejos grunoes
4

我尝试输入代码

import java.io.*; 

public class ReadFromFile2 { 
    public static void main(String[] args)throws Exception {  
        File file = new File("movies.dat");  
        BufferedReader br = new BufferedReader(new FileReader(file)); 

        try {
            String line; 
            while ((line = br.readLine()) != null){
                String[] var = line.split(" ");

                System.out.println(line); 

            } 
        } finally {
            br.close();
        }
    }       
}

Answer 1

您需要分割多个空格，而不仅仅是一个。同样，花了一些时间才知道标题的空格在哪里结束，下一列开始。我使用的imdb功能是7位数字。我还特别注意不要被最后那短行或标题行弄糊涂了。这是怎么出来的。

import java.io.*;

public class ReadFromFile2 {
    public static void main(String[] args) throws Exception {
        File file = new File("movies.dat");
        BufferedReader br = new BufferedReader(new FileReader(file));
        boolean first = true;
        try {
            String line;
            while ((line = br.readLine()) != null) {
                line = line.trim(); //get rid of leading and trailing spaces to be safe
                String[]
                var = line.split("\\s+"); //split on space or multiple spaces
                if (first) {
                    System.out.println(var [0] + " " +
                        var [1]); //headers
                    first = false;
                } else if (var.length >= 2) { //enough to write

                    for (int i = 0; i <
                        var.length; i++) {
                        if (var [i].matches("[0-9]+") &&
                            var [i].length() == 7) { //imdb
                            break;
                        }
                        if (i > 0) {
                            System.out.print(" ");
                        }
                        System.out.print(var [i]);
                    }
                    System.out.println();
                }

            }
        } finally {
            br.close();
        }
    }
}

从文件接收和打印特定数据

1 个答案: