CSVParser.java

package com.argcv.util;

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

public class CSVParser {
	final static int defaultMaxWidth = 20;

	public static String[] parse(BufferedReader br, int maxWidth) {
		String[] dataItem = new String[maxWidth];
		int dataId = 0;
		String line = "";
		try {
			line = br.readLine();
			if (line == null) {
				System.err.println("line is null");
				return null;
			}
		} catch (IOException e1) {
			e1.printStackTrace();
			return null;
		}
		char[] charArray = line.toCharArray();
		boolean quotFlag = false;
		boolean finishFlag = false;
		StringBuffer sb = new StringBuffer();
		int arrayLen = charArray.length;
		boolean again = false;
		do { 
			if (again) {
				try {
					line = br.readLine();
					if (line == null) {
						System.err.println("line is null");
						return null;
					} else {
						// System.err.println(line);
					}
				} catch (IOException e) {
					e.printStackTrace();
					return null;
				}
				charArray = line.toCharArray();
				arrayLen = charArray.length;
			}
			for (int i = 0; i < arrayLen; i++) {
				switch (charArray[i]) {
				case ',':
					if (!quotFlag) {
						dataItem[dataId] = sb.toString();
						sb = new StringBuffer();
						dataId++;
						if (dataId >= maxWidth) {
							finishFlag = true;
							break;
						}
					} else {
						sb.append(",");
					}
					break;
				case '\"':
					if ((i == arrayLen - 1) || (charArray[i + 1] != '\"') || !quotFlag) {
						quotFlag = quotFlag ? false : true;
					} else {
						sb.append("\"");
						i++;
					}
					break;
				default:
					sb.append(charArray[i]);
				}
				// System.out.println(String.format("%c:%x:%s", charArray[i],(int)charArray[i],quotFlag?"true":"false"));
				// System.out.println(charArray[i] + ":" + quotFlag);
				if (finishFlag)
					break;
			}
			again = true;
			if(quotFlag) sb.append("\n");
		} while (quotFlag);
		if (dataId < maxWidth) {
			dataItem[dataId] = sb.toString();
		}
		// System.err.println("jump out");
		return dataItem;
	}

	public static String[] parse(BufferedReader br) {
		return parse(br, defaultMaxWidth);
	}

	public static void main(String[] args) throws FileNotFoundException {
		BufferedReader br = new BufferedReader(new FileReader(new File("/home/yu/Downloads/nottebest.csv"))); // 文件名
		String[] fields = CSVParser.parse(br); // 调用，有两种方法，一种直接传入br,默认20列。否则第二个参数，比如CSVParser.parse(br,20);
		while ((fields = CSVParser.parse(br)) != null) { // 返回null 为读文件结束
			for (String f : fields) {
				System.out.print(f + "\t");
			}
			System.out.println();
		}
	}
}