解析 CSV 行中的空位置时如何避免触发 ArrayIndexOutOfBoundsException？

发布于 2024-11-18 15:44:20 字数 958 浏览 7 评论 0原文

String[] values = line.split(",");

Long locId = Long.parseLong(replaceQuotes(values[0]));
String country = replaceQuotes(values[1]);
String region = replaceQuotes(values[2]);
String city = replaceQuotes(values[3]);
String postalCode = replaceQuotes(values[4]);
String latitude = replaceQuotes(values[5]);
String longitude = replaceQuotes(values[6]);
String metroCode = replaceQuotes(values[7]);
String areaCode = replaceQuotes(values[8]);

//...

public String replaceQuotes(String txt){
    txt = txt.replaceAll("\"", "");
    return txt;
}

我使用上面的代码来解析包含以下格式数据的 CSV：

828,"US","IL","Melrose Park","60160",41.9050,-87.8641,602,708

但是，当我遇到如下所示的一行数据时，我得到 java.lang.ArrayIndexOutOfBoundsException: 7< /strong>

1,"O1","","","",0.0000,0.0000,,

这是否意味着每当我尝试访问 values[7] 处的值时，都会抛出异常？

如果是这样，如何解析文本行该位置不包含数据的行？

原文

String[] values = line.split(",");

Long locId = Long.parseLong(replaceQuotes(values[0]));
String country = replaceQuotes(values[1]);
String region = replaceQuotes(values[2]);
String city = replaceQuotes(values[3]);
String postalCode = replaceQuotes(values[4]);
String latitude = replaceQuotes(values[5]);
String longitude = replaceQuotes(values[6]);
String metroCode = replaceQuotes(values[7]);
String areaCode = replaceQuotes(values[8]);

//...

public String replaceQuotes(String txt){
    txt = txt.replaceAll("\"", "");
    return txt;
}

I'm using the code above to parse a CSV with data in this format:

828,"US","IL","Melrose Park","60160",41.9050,-87.8641,602,708

However, when I encounter a line of data such as the following I get java.lang.ArrayIndexOutOfBoundsException: 7

1,"O1","","","",0.0000,0.0000,,

Does this mean that any time I even try to access the value at values[7], an Exception will be thrown?

If so, how do I parse lines that don't contain data in that position of the text line?

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追我者格杀勿论 2024-11-25 15:44:20

首先，String.split() 不是一个出色的 CSV 解析器：它不知道引号，并且一旦引用值之一包含逗号，它就会陷入混乱。

话虽这么说，默认情况下 String.split() 省略空尾随元素。您可以通过使用双参数变体：

String[] values = line.split(",", -1);

-1（或任何负值）意味着数组将根据需要尽可能大。
使用正值给出了要完成的最大分割量（这意味着超出该值的所有内容都将是单个值，即使它包含逗号）。
0（如果使用单参数值，则为默认值）意味着数组将根据需要尽可能大，但是空尾随值将被排除在数组之外（正如发生在您身上的情况一样）。

First of all, String.split() is not a great CSV parser: it doesn't know about quotes and will mess up as soon as one of your quoted values contains a comma.

That being said, by default String.split() leaves out empty trailing elements. You can influence that by using the two-argument variant:

String[] values = line.split(",", -1);

-1 (or any negative value) means that the array will be as large as necessary.
Using a positive value gives a maximum amount of splits to be done (meaning that everything beyond that will be a single value, even if it contains a comma).
0 (the default if you use the one-argument value) means that the array will be as large as necessary, but empty trailing values will be left out of the array (exactly as it happens to you).

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