java - 根据行中包含的数字对文件中的行进行排序

Question

我有以下文本文件(offline.txt):

# Timestamp, X, Y, MAC Address of AP, RSS
1395444273179 35.19967269897461 19.1965389251709 28:c6:8e:85:80:d3 -71
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:8e:e9:a1 -75
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:8e:e9:a2 -74
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:8e:e9:b1 -84
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:8e:e9:b2 -85
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:8e:e9:b0 -85
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:8e:e9:a0 -74
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:87:04:41 -75
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:87:04:40 -73
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:87:04:42 -74
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:87:04:52 -96
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:87:04:50 -97

我想根据文件第五列中的数字按降序对文件行进行排序，如果某个值重复，则重复值的顺序并不重要。

例如，这是我想要的上一个特定文本文件的所需输出(offline_out.txt):

# Timestamp, X, Y, MAC Address of AP, RSS
1395444273179 35.19967269897461 19.1965389251709 28:c6:8e:85:80:d3 -71
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:87:04:40 -73
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:87:04:42 -74
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:8e:e9:a0 -74
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:8e:e9:a2 -74
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:8e:e9:a1 -75
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:8e:e9:b1 -84
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:8e:e9:b2 -85
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:8e:e9:b0 -85
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:87:04:52 -96
1395444273179 35.19967269897461 19.1965389251709 00:1a:1e:87:04:50 -97

我知道如何读取文件，并且我知道java中的“排序”功能可以帮助我排序。 所以我的想法是提取第五行中的所有数字，将它们保存在一个 vector 中，然后对 vector 进行排序，并找到一种将数字与特定行相关联的方法，这样一旦数字被排序，行也会被排序，然后保存它们到另一个文件。关于如何编程有什么想法吗？

这是我到目前为止的程序:

public class extract {
    public static void main (String[] args) throws java.lang.Exception
    {
    File inputFile = new File("offline.txt");
    File tempFile = new File("offline_out.txt");

    BufferedReader reader = new BufferedReader(new FileReader(inputFile));
    BufferedWriter writer = new BufferedWriter(new FileWriter(tempFile));

    //while to read all the lines, but how can I store only the numbers to a vector an associate them to a specific row?
        while((currentLine = reader.readLine()) != null) {
           }
    }

    //to save the output file
    boolean successful = tempFile.renameTo(inputFile);

    }

Answer 1

创建一个具有两个字段的值对象 bean 类:number 和 line。实现 comparable 并重写该类中的 compareTo 方法。当您扫描文件时，填充此 Bean 类的 ArrayList。然后对ArrayList进行排序。