请教：parse CSV文件 - 未名空间MITBBS历史存档

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请教：parse CSV文件

请教：parse CSV文件# Java - 爪哇娇娃

F*e2009-02-11 08:02

1 楼

这个文件是MySQL dump出来的CSV, 所以每个column都是逗号（，）分开的，问题是有
一个column是blob, dump出来是text, text里本身含有逗号，在文中显示 \, 比如说这
一行：
1,2,a\, b,4
一共应该是4个columns, 如果用String.split(",")的话，就把当中的text给拆掉了。
应该输出是
1
2
a, b
4
怎么搞啊？包子答谢！ //bow

Z*e2009-02-11 08:02

2 楼

简单方法：现改dump文件的结构，把blob放在最后一个column，然后用split(regex,
limit)函数限制最多能分出来的列数

【在 F**e 的大作中提到】

: 这个文件是MySQL dump出来的CSV, 所以每个column都是逗号（，）分开的，问题是有
: 一个column是blob, dump出来是text, text里本身含有逗号，在文中显示 \, 比如说这
: 一行：
: 1,2,a\, b,4
: 一共应该是4个columns, 如果用String.split(",")的话，就把当中的text给拆掉了。
: 应该输出是
: 1
: 2
: a, b
: 4

g*g2009-02-11 08:02

3 楼

A simple solution, replace "\," with a special string which won't occur,
e.g "__temp__", split, then replace "__temp__" with "," one by one.
If you want good performance, use StringTokenizer

【在 F**e 的大作中提到】

b*y2009-02-11 08:02

4 楼

I guess you should dump to TAB separated file, if possible. To keep it
simple and easy for ya.

c*t2009-02-11 08:02

5 楼

The presence of \, might indicate that \\ or other escape sequences.
Couple with error detection, it is a pain to write a perfect parser
by hand.
(btw, I think the standard CSV uses double quote for literals. It
is a bit strange to use \,)
Java's regular expression is not particularly efficient.
The best way is to use a lex tool (like my CookCC which is for Java)
to deal with this situation.

【在 g*****g 的大作中提到】

: A simple solution, replace "\," with a special string which won't occur,
: e.g "__temp__", split, then replace "__temp__" with "," one by one.
: If you want good performance, use StringTokenizer