如何从文本文件中提取数据并用 Java 写入 CSV 文件

Question

我有一个文本文件，其中包含参考、姓名、地址、金额、dateTo、dateFrom 和必填列，格式如下：

"120030125 J Blog  23, SOME HOUSE,                 259.44  21-OCT-2013  17-NOV-2013"
"                  SQUARE, STREET, LEICESTER,"
                   LE1 2BB

"120030318 R Mxx   37, WOOD CLOSE, BIRMINGHAM,     121.96  16-OCT-2013  17-NOV-2013  Y"                      
"                  STREET, NN18 8DF"

"120012174 JE xx   25, SOME HOUSE, QUEENS          259.44  21-OCT-2013  17-NOV-2013"
"                  SQUARE, STREET, LEICESTER,"
                   LE1 2BB

"100154992 DL x    23, SOME HOUSE, QUEENS          270.44  21-OCT-2013  17-NOV-2013  Y"             
"                  SQUARE, STREET, LEICESTER,"
                   LE1 2BC

我只对每个字符串的第一行感兴趣，想提取reference、name、amount、dateTo 和dateFrom 列中的数据，并希望将它们写入CSV 文件。目前我只能编写以下代码并提取第一行并去掉开始和结束的双引号。输入文件包含空格，输出文件也包含空格。

public class ReadTxt {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader("C:/Users/me/Desktop/input.txt"));
        String pattern = "\"\\d\\d\\d\\d";

        // Create a Pattern object
        Pattern r = Pattern.compile(pattern);
        int i;
        ArrayList<String> list = new ArrayList<String>();

        boolean a = true;
        PrintWriter out = new PrintWriter(new PrintWriter("C:/Users/me/Desktop/Output.txt"), a);

        try {
            String line = br.readLine();

            while (line != null) {
                Matcher m = r.matcher(line);

                if (m.find()) {
                    String temp;
                    temp = line.substring(1, line.length() - 1);
                    list.add(temp);
                }
                else {
                // do nothing
                }

                line = br.readLine();
            }
        }
        finally {
            br.close();
        }

        for (i = 0; i < list.size(); i++) {
            out.println(list.get(i));
        }

        out.flush();
        out.close();
    }
}

上面的代码将创建一个带有以下输出的文本文件：

120030125  J Blog   23, SOME HOUSE, QUEENS       259.44  21-OCT-2013  17-NOV-2013
120030318  R Mxx    37, WOOD CLOSE, BIRMINGHAM,  121.96  16-OCT-2013  17-NOV-2013  Y                      
120012174  JE xx    25, SOME HOUSE, QUEENS       259.44  21-OCT-2013  17-NOV-2013
100154992  DL x     23, SOME HOUSE, QUEENS       259.44  21-OCT-2013  17-NOV-2013  Y

我的预期输出如下，但在 csv 文件中：

120030125  J Blog  259.44  21-OCT-2013  17-NOV-2013
120030318  R Mxx   121.96  16-OCT-2013  17-NOV-2013                        
120012174  JE xx   259.44  21-OCT-2013  17-NOV-2013
100154992  DL x    259.44  21-OCT-2013  17-NOV-2013  

任何建议、教程链接或帮助将不胜感激，因为我不是 Java 专家。我确实尝试在互联网上查找教程，但找不到任何对我有用的教程。

Answer 1

在这里，测试一下。我只是使用了一个数组，但你可以在你的数组中实现必要的代码。我更改了一些地址（查看数组中的第 2 和第 3 个地址）以在不同的位置有空格和没有空格进行测试。

public class SplitData {

    public static void main(String[] args) {
        String[] array = {"120030125  J Blog   23, SOME HOUSE, QUEENS       259.44  21-OCT-2013  17-NOV-2013",
            "120030318  R Mxx    37,WOODCLOSE,BIRMINGHAM,  121.96  16-OCT-2013  17-NOV-2013  Y 0",
            "120012174  JE xx    25, SOME HOUSE,QUEENS       259.44  21-OCT-2013  17-NOV-2013",
            "100154992  DL x     23, SOME HOUSE, QUEENS       259.44  21-OCT-2013  17-NOV-2013  Y"  
        };

        String s1 = null;
        String s2 = null;
        String s3 = null;
        String s4 = null;
        String s5 = null;
        for (String s : array) {
            String[] split = s.split("\\s+");
            s1 = split[0];
            s2 = split[1] + " " + split[2];
            for (String string: split) {
                if (string.matches("\\d+\\.\\d{2}")) {
                    s3 = string;
                    break;
                }
            }
            String[] newArray = s.substring(s.indexOf(s3)).split("\\s+");
            s4 = newArray[1];
            s5 = newArray[2];

            System.out.printf("%s\t%s\t%s\t%s\t%s\n", s1, s2, s3, s4, s5);
        }
    }  
}

输出

120030125   J Blog  259.44  21-OCT-2013 17-NOV-2013
120030318   R Mxx   121.96  16-OCT-2013 17-NOV-2013
120012174   JE xx   259.44  21-OCT-2013 17-NOV-2013
100154992   DL x    259.44  21-OCT-2013 17-NOV-2013

Answer 2

public static void main (String[] args) throws IOException {
  BufferedReader br = new BufferedReader (new FileReader ("D:/input.txt"));
  String pattern = "\"\\d\\d\\d\\d";

  // Create a Pattern object
  Pattern r = Pattern.compile (pattern);
  int i;
  ArrayList<String> list = new ArrayList<String> ();

  boolean a = true;
  PrintWriter out = new PrintWriter (new PrintWriter ("D:/Output.csv"), a);

  try {
      String line = br.readLine ();
      line= line.trim ();
      while (line != null) {
      Matcher m = r.matcher (line);
      if (m.find ()) {
          String temp;
          temp = line.substring (0, 19) + " "
                + line.substring (51, line.length () - 1);          
          temp = temp.replaceAll ("[ ]+", " ").replace ("\"", "");
          String[] array = temp.split ("[ ]");
          temp = array[0] +","+ array[1] +" "+ array[2]+","+ array[3]+","+ array[4]+","+ array[5];
          list.add (temp);
      } else {
          // do nothing
      }

      line = br.readLine ();
      }
  }   finally {
      br.close ();
  }

  for (i = 0; i < list.size (); i++) {
      out.println (list.get (i));
  }

  out.flush ();
  out.close ();
  }

输出

120030125,J Blog,259.44,21-OCT-2013,17-NOV-2013
120030318,R Mxx,121.96,16-OCT-2013,17-NOV-2013
120012174,JE xx,259.44,21-OCT-2013,17-NOV-2013
100154992,DL x,270.44,21-OCT-2013,17-NOV-2013