Java CSV File Parse parseCsv(InputStream csvInput)

Description

CSV content parser.

License

Open Source License

Parameter

Parameter	Description
csvInput	The InputStream with the CSV contents.

Return

A two-dimensional List of Strings representing the rows and columns of the CSV.

Declaration

public static List<List<String>> parseCsv(InputStream csvInput) 

Method Source Code

//package com.java2s;
/*//  w  ww . j  a  v a  2  s. c  o m
 * net/balusc/util/CsvUtil.java
 * 
 * Copyright (C) 2006 BalusC
 * 
 * This program is free software: you can redistribute it and/or modify it under the terms of the
 * GNU Lesser General Public License as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License along with this library.
 * If not, see <http://www.gnu.org/licenses/>.
 */

import java.io.BufferedReader;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;

import java.util.List;

public class Main {
    private static final char DEFAULT_CSV_SEPARATOR = ',';

    /**
     * CSV content parser. Convert an InputStream with the CSV contents to a two-dimensional List
     * of Strings representing the rows and columns of the CSV. Each CSV record is expected to be
     * separated by the default CSV field separator, a comma.
     * @param csvInput The InputStream with the CSV contents.
     * @return A two-dimensional List of Strings representing the rows and columns of the CSV.
     */
    public static List<List<String>> parseCsv(InputStream csvInput) {
        return parseCsv(csvInput, DEFAULT_CSV_SEPARATOR);
    }

    /**
     * CSV content parser. Convert an InputStream with the CSV contents to a two-dimensional List
     * of Strings representing the rows and columns of the CSV. Each CSV record is expected to be
     * separated by the specified CSV field separator.
     * @param csvInput The InputStream with the CSV contents.
     * @param csvSeparator The CSV field separator to be used.
     * @return A two-dimensional List of Strings representing the rows and columns of the CSV.
     */
    public static List<List<String>> parseCsv(InputStream csvInput, char csvSeparator) {

        // Prepare.
        BufferedReader csvReader = null;
        List<List<String>> csvList = new ArrayList<List<String>>();
        String csvRecord = null;

        // Process records.
        try {
            csvReader = new BufferedReader(new InputStreamReader(csvInput, "UTF-8"));
            while ((csvRecord = csvReader.readLine()) != null) {
                csvList.add(parseCsvRecord(csvRecord, csvSeparator));
            }
        } catch (IOException e) {
            throw new RuntimeException("Reading CSV failed.", e);
        } finally {
            if (csvReader != null)
                try {
                    csvReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
        }

        return csvList;
    }

    /**
     * CSV record parser. Convert a CSV record to a List of Strings representing the fields of the
     * CSV record. The CSV record is expected to be separated by the specified CSV field separator.
     * @param record The CSV record.
     * @param csvSeparator The CSV field separator to be used.
     * @return A List of Strings representing the fields of each CSV record.
     */
    private static List<String> parseCsvRecord(String record, char csvSeparator) {

        // Prepare.
        boolean quoted = false;
        StringBuilder fieldBuilder = new StringBuilder();
        List<String> fields = new ArrayList<String>();

        // Process fields.
        for (int i = 0; i < record.length(); i++) {
            char c = record.charAt(i);
            fieldBuilder.append(c);

            if (c == '"') {
                quoted = !quoted; // Detect nested quotes.
            }

            if ((!quoted && c == csvSeparator) // The separator ..
                    || i + 1 == record.length()) // .. or, the end of record.
            {
                String field = fieldBuilder.toString() // Obtain the field, ..
                        .replaceAll(csvSeparator + "$", "") // .. trim ending separator, ..
                        .replaceAll("^\"|\"$", "") // .. trim surrounding quotes, ..
                        .replace("\"\"", "\""); // .. and un-escape quotes.
                fields.add(field.trim()); // Add field to List.
                fieldBuilder = new StringBuilder(); // Reset.
            }
        }

        return fields;
    }
}

Related

1. csvLineParse(String line, char delimiter)
2. csvSplitLine(String line, char fieldSeparator)
3. parse(final String csvString)
4. parseCsv(InputStream fileStream)
5. parseCSV(String csv)
6. parseCSV(String csv)
7. parseCSV(String csvString)