Question

我有一个Justice_League.csv文件，它们之间有四行逗号。我想计算每行中的字符数，并将该数字转换为十六进制。

以下是Justice_League.csv的内容：

Bruce Wayne,Batman,None,Gotham City,Robin,The Joker                 43      2B
Oliver Queen,Green Arrow,None,Star City,Speedy,Deathstroke          50      32
Clark Kent,Superman,Flight,Metropolis,None,Lex Luthor               46      2E
Bart Allen,The Flash,Speed,Central City,Kid Flash,Professor Zoom    52      34

正如您所看到的，我已经手写了字符并在其旁边写了十六进制值。现在我需要用Java完成这个。这就是我到目前为止所拥有的。有人可以帮帮我吗？

public String convertCSVToFlat (Exchange exchange) throws Exception {
    String csv="Justice_League.csv";
    BufferedReader bReader = new BufferedReader(new FileReader(csv));
    String line = "";
    int count = 0;
    String str[] = new String[200];
    int[] a = new int[24];
    String[] hexNumber = new String[4];
    try {
        bReader.readLine();
        int characterSum = 0;
        int i = 0;  
        while((line = bReader.readLine()) != null) {
             String[] f=line.split(",");
             a[count]=Integer.parseInt(f[2]);
             str[count]=f[1];            
             count++;
             characterSum += line.length();
             hexNumber[i] = Integer.toHexString(characterSum);
             i++;
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
    bReader.close();
    return hexNumber.toString();

Answer 1

我建议你阅读String.split的javadoc。我认为当你这样做时你误解了这个概念：

String [] f = line.split（“，”）;

一个[数] =的Integer.parseInt（F [2]）; // - ＆GT;这里是java.lang.NumberFormatException！

避免在代码中使用“魔术”数字，例如int[] a = new int[24];。为什么24？

嗯，这是一个做你想做的事情的版本。也许这不是最好的方法，但它有效。

public void convertCSVToFlat () throws Exception {
    String csv="Justice_League.csv";
    BufferedReader bReader = new BufferedReader(new FileReader(csv));

    //We're storing the values at this 3 arraylists, 
    //but a better approach is using an object to hold'em
    ArrayList<String> lines = new ArrayList<String>();
    ArrayList<Integer> chars = new ArrayList<Integer>();
    ArrayList<String> hex = new ArrayList<String>();

    String line = "";
    try {
        while((line = bReader.readLine()) != null) {
            lines.add(line);
            //I'm assuming that you don't want to count the commas and spaces.
            //If you want to, comment the next line
            line = line.replaceAll(",", "").replaceAll(" ", "");
            int c = line.length(); //count remaining chars...
            chars.add(c);
            hex.add(Integer.toHexString(c));
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
    bReader.close();

    //Just to show the results
    for (int i = 0; i < lines.size(); i++) {
        System.out.print(lines.get(i));
        System.out.print("\t" + chars.get(i));
        System.out.println("\t" + hex.get(i));
    }
}

就像我之前说过的，这是一种解决这个问题的方法。您应该尝试其他选项来解决这个问题，以提高您的知识......

如何计算csv文件中一行中的字符数

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