Question

代码段将CSV文件拆分为多个CSV文件，并将第一列内容写入子CSV文件。我在此代码中观察到的是列标题“UNIQUE ID”仅出现在FIRST CSV文件中。以下CSV文件仅包含没有标题的数据。为了获得我想到的所有文件的头文件使用ArrayList，以便我可以将头文件放在ArrayList的第一个索引和之后的其余数据。但我悲惨地失败了。

我需要有关如何修改代码的建议或帮助，以便所有子文件都应该有一个额外的UNIQUE IDENTIFIER行作为第一行的列数据。我正在粘贴我尝试过但不起作用的代码。 Child csv should look like this This is what I am getting

public static void myFunction(int lines, int files) throws FileNotFoundException, IOException {


    String inputfile = "C:/Users/Downloads/CONSOLIDATED.csv";
    BufferedReader br = new BufferedReader(new FileReader(inputfile));
    String strLine = null;
    for (int i = 1; i <= files; i++) {

        FileWriter fstream1 = new FileWriter("C:/Users/Downloads/FileNumber_" + i + ".csv");
        BufferedWriter out = new BufferedWriter(fstream1);

        for (int j = 0; j < lines; j++) {

            strLine = br.readLine();
            if (strLine != null) {

                String strar[] = strLine.split(",");
                ArrayList<String> al=new ArrayList<String>();
                al.add(0,"Unique Identifier");
                al.add(1,strar[0]);
                char c[] = al.toString().toCharArray();
                out.write(c);
                out.newLine();
            }
        }
        out.close();
    }
    br.close();
}

Answer 1

您的问题是您没有将标题排除在循环之外。尝试在主循环之前读取第一行的内容并将标题存储在List中。然后，每次创建新文件时，在开始内循环之前，在每个文件的第一行写入标题。

public static void myFunction(int lines, int files) throws FileNotFoundException, IOException {


    String inputfile = "C:/Users/Downloads/CONSOLIDATED.csv";
    BufferedReader br = new BufferedReader(new FileReader(inputfile));
    String strLine = br.readLine(); //here you have the headers
    String[] headers=strLine.split(",");

    for (int i = 1; i <= files; i++) {

        FileWriter fstream1 = new FileWriter("C:/Users/Downloads/FileNumber_" + i + ".csv");
        BufferedWriter out = new BufferedWriter(fstream1);

        out.write(headers[0]);

        for (int j = 0; j < lines; j++) {
            out.newLine();
            strLine = br.readLine();
            if (strLine != null) {

              String strar[] = strLine.split(",");
              out.write(strar[0]);
            }
        }
        out.close();
    }
    br.close();
}

使用charArray（）将ArrayList写入BufferedWriter

1 个答案: