SalesForce Apex CSV Parser

gistfile1.java

/**
 * Used to read a delimited file.
 */
public class SSSCsvReader {
	private String delim = ',';
	// the input data
	private String[] buffer;
	
	public SSSCsvReader(String data){
		this.buffer = data.split('\n'); 
	}
	
	public SSSCsvReader(String data, String delim){
		this.buffer = data.split('\n'); 
		this.delim = delim;
	}
	
	/**
	 * Read and parse next available line.  Return null if end of stream.
	 */
	public String[] readLine(){
		if(buffer.size() == 0)
			return null;
		String line = this.buffer.remove(0);
		String[] parts = new String[] {};
		while(line != ''){
			Integer next = 0;
			if(line.startsWith('"')){
				line = line.substring(1); // strip initial
				Integer quoteIndex = findQuote(line, 0);
				while(quoteIndex == -1){
					if(buffer.size() == 0){
						// EOT!
						quoteIndex = line.length();
					} else { 
						// grab the next line
						Integer skip = line.length();
						line += '\n' + this.buffer.remove(0);
						quoteIndex = findQuote(line, skip);
					}
				}
				// advance to comma
				next = quoteIndex + 1;
				parts.add(line.substring(0, quoteIndex).replace('""', '"'));
			} else {
				next = line.indexOf(this.delim, next);
				if(next == -1)
					next = line.length();
				// NB in Substring, "endindex" is the index of the character AFTER the last index to get
				parts.add(line.substring(0, next));
			}		
			if(next == line.length() - 1)
				// case of a terminating comma.
				parts.add('');
			line = next < line.length() ? line.substring(next+1) : '';
		}
		if(parts.size() == 0)
			// empty string - we still want to return something...
			parts.add('');
		return parts;
	}
	
	static private Pattern quotePattern = Pattern.compile('(?<!")"(?!")');
	/**
	 * Find next quote in the line
	 */
	private Integer findQuote(String line, Integer skip){
		Matcher m = quotePattern.matcher(line);
		m.region(skip, m.regionEnd());
		if(!m.find())
			return -1;
		return m.start();
	}
}

Doesn't work properly. Multiline cells are not handled correctly. You cannot just use split. Also, correct line delimiter is CRLF (\r\n), not LF (\n).

Hi TrangOul, thanks for highlighting the issues.
This gist is a fork of https://gist.github.com/nicocrm/858086, where you can find appropriate comments. It's been a while since I worked on such a scenario, so I cannot offer any workarounds at the moment.