在java中解析CSV文件，并使用空值进行delaing [英] Parse CSV file in java, and delaing with empty values

问题描述

我正在将CSV文件解析到我的程序中，在，元素中拆分值，并且它工作正常，除非我有缺少值的行。

I am parsing a CSV file into my program, spliting the values at the , element, and it's working fine, except for when I have lines that have missing values.

解析器的工作方式如下：

The parser is working like this:

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class CsvReader
{
    private static final String DELIMITER = ",";
    private final BufferedReader br;
    private final String path;

    public CsvReader(final String path) throws IOException
    {
        this.path = path;
        this.br = new BufferedReader(new FileReader(path));
    }

    public String[] nextLine() throws IOException
    {
        final String line = br.readLine();
        return (line == null) ? new String[0] : line.split(DELIMITER);
    }
}

数据行如下所示（一行为例如）：

The lines of data look like this (one line as an example):

J1024205,5028197000004,1,,00,20150603,,Accessories,Factory Test Article (m),ENG,010,110,5,T1,99,99,,,99,99,99,ZZ,ZZ,,5028197242053,30,35028197242054,6,,,OPZ848,3013607800239,OPZ848,,,,50,,

文件中的大多数行都包含： 50,85028197242127,8640

Most of the lines in the file complete with this: 50,85028197242127,8640

但在某些行上，数据丢失了，所以结尾如下： 50 ,,

But on some lines, the data is missing, so it ends like this: 50,,

处理文件时，这些行导致 java.lang.ArrayIndexOutOfBoundsException 。

When the file is being processed, these lines are causing a java.lang.ArrayIndexOutOfBoundsException.

如果我知道文件中的对象数量将保持不变，我该如何才能最好地解决这个问题？

How can I best deal with this, if I know that the numbers of objects in the file will remain constant?

我被告知我需要用空值替换空值。

I've been told that I need to replace empty values with a null value.

推荐答案

来自<$ c $的Javadoc c> String.split（正则表达式）

此方法的作用就像通过调用给定表达式和limit参数为零的双参数split方法一样。 结果数组中不包含尾随空字符串。

因此，在您的情况下，当字符串以 ,, 结尾，空字符串不会是结果数组的一部分。

So, in your case, when the string ends with ,,, empty strings wont be part of the resultant array.

要修复： 使用此分割变体

line.split(DELIMITER, -1);

这将包括所有尾随空字符串。所以你不会得到例外。

This will include all trailing empty strings. So you won't get an exception.

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