We would like to know how to cVS reader.
//package au.com.bytecode.opencsv; /** Copyright 2005 Bytecode Pty Ltd. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ import java.io.BufferedReader; import java.io.IOException; import java.io.Reader; import java.util.ArrayList; import java.util.List; /** * A very simple CSV reader released under a commercial-friendly license. * * @author Glen Smith * */ public class CSVReader { private BufferedReader br; private boolean hasNext = true; private char separator; private char quotechar; private int skipLines; private boolean linesSkiped; /** The default separator to use if none is supplied to the constructor. */ public static final char DEFAULT_SEPARATOR = ','; /** * The default quote character to use if none is supplied to the * constructor. */ public static final char DEFAULT_QUOTE_CHARACTER = '"'; /** * The default line to start reading. */ public static final int DEFAULT_SKIP_LINES = 0; /** * Constructs CSVReader using a comma for the separator. * * @param reader * the reader to an underlying CSV source. */ public CSVReader(Reader reader) { this(reader, DEFAULT_SEPARATOR); } /** * Constructs CSVReader with supplied separator. * * @param reader * the reader to an underlying CSV source. * @param separator * the delimiter to use for separating entries. */ public CSVReader(Reader reader, char separator) { this(reader, separator, DEFAULT_QUOTE_CHARACTER); } /** * Constructs CSVReader with supplied separator and quote char. * * @param reader * the reader to an underlying CSV source. * @param separator * the delimiter to use for separating entries * @param quotechar * the character to use for quoted elements */ public CSVReader(Reader reader, char separator, char quotechar) { this(reader, separator, quotechar, DEFAULT_SKIP_LINES); } /** * Constructs CSVReader with supplied separator and quote char. * * @param reader * the reader to an underlying CSV source. * @param separator * the delimiter to use for separating entries * @param quotechar * the character to use for quoted elements * @param line * the line number to skip for start reading */ public CSVReader(Reader reader, char separator, char quotechar, int line) { this.br = new BufferedReader(reader); this.separator = separator; this.quotechar = quotechar; this.skipLines = line; } /** * Reads the entire file into a List with each element being a String[] of * tokens. * * @return a List of String[], with each String[] representing a line of the * file. * * @throws IOException * if bad things happen during the read */ public List readAll() throws IOException { List allElements = new ArrayList(); while (hasNext) { String[] nextLineAsTokens = readNext(); if (nextLineAsTokens != null) allElements.add(nextLineAsTokens); } return allElements; } /** * Reads the next line from the buffer and converts to a string array. * * @return a string array with each comma-separated element as a separate * entry. * * @throws IOException * if bad things happen during the read */ public String[] readNext() throws IOException { String nextLine = getNextLine(); return hasNext ? parseLine(nextLine) : null; } /** * Reads the next line from the file. * * @return the next line from the file without trailing newline * @throws IOException * if bad things happen during the read */ private String getNextLine() throws IOException { if (!this.linesSkiped) { for (int i = 0; i < skipLines; i++) { br.readLine(); } this.linesSkiped = true; } String nextLine = br.readLine(); if (nextLine == null) { hasNext = false; } return hasNext ? nextLine : null; } /** * Parses an incoming String and returns an array of elements. * * @param nextLine * the string to parse * @return the comma-tokenized list of elements, or null if nextLine is null * @throws IOException if bad things happen during the read */ private String[] parseLine(String nextLine) throws IOException { if (nextLine == null) { return null; } List tokensOnThisLine = new ArrayList(); StringBuffer sb = new StringBuffer(); boolean inQuotes = false; do { if (inQuotes) { // continuing a quoted section, reappend newline sb.append("\n"); nextLine = getNextLine(); if (nextLine == null) break; } for (int i = 0; i < nextLine.length(); i++) { char c = nextLine.charAt(i); if (c == quotechar) { // this gets complex... the quote may end a quoted block, or escape another quote. // do a 1-char lookahead: if( inQuotes // we are in quotes, therefore there can be escaped quotes in here. && nextLine.length() > (i+1) // there is indeed another character to check. && nextLine.charAt(i+1) == quotechar ){ // ..and that char. is a quote also. // we have two quote chars in a row == one quote char, so consume them both and // put one on the token. we do *not* exit the quoted text. sb.append(nextLine.charAt(i+1)); i++; }else{ inQuotes = !inQuotes; // the tricky case of an embedded quote in the middle: a,bc"d"ef,g if(i>2 //not on the begining of the line && nextLine.charAt(i-1) != this.separator //not at the begining of an escape sequence && nextLine.length()>(i+1) && nextLine.charAt(i+1) != this.separator //not at the end of an escape sequence ){ sb.append(c); } } } else if (c == separator && !inQuotes) { tokensOnThisLine.add(sb.toString()); sb = new StringBuffer(); // start work on next token } else { sb.append(c); } } } while (inQuotes); tokensOnThisLine.add(sb.toString()); return (String[]) tokensOnThisLine.toArray(new String[0]); } /** * Closes the underlying reader. * * @throws IOException if the close fails */ public void close() throws IOException{ br.close(); } } /////////////////////////////////////////// package au.com.bytecode.opencsv; /** Copyright 2005 Bytecode Pty Ltd. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ import java.io.IOException; import java.io.StringReader; import java.util.List; import junit.framework.TestCase; public class CSVReaderTest extends TestCase { CSVReader csvr; /** * Setup the test. */ protected void setUp() throws Exception { StringBuffer sb = new StringBuffer(); sb.append("a,b,c").append("\n"); // standard case sb.append("a,\"b,b,b\",c").append("\n"); // quoted elements sb.append(",,").append("\n"); // empty elements sb.append("a,\"PO Box 123,\nKippax,ACT. 2615.\nAustralia\",d.\n"); sb.append("\"Glen \"\"The Man\"\" Smith\",Athlete,Developer\n"); // Test quoted quote chars sb.append("\"\"\"\"\"\",\"test\"\n"); // """""","test" representing: "", test sb.append("\"a\nb\",b,\"\nd\",e\n"); csvr = new CSVReader(new StringReader(sb.toString())); } /** * Tests iterating over a reader. * * @throws IOException * if the reader fails. */ public void testParseLine() throws IOException { // test normal case String[] nextLine = csvr.readNext(); assertEquals("a", nextLine[0]); assertEquals("b", nextLine[1]); assertEquals("c", nextLine[2]); // test quoted commas nextLine = csvr.readNext(); assertEquals("a", nextLine[0]); assertEquals("b,b,b", nextLine[1]); assertEquals("c", nextLine[2]); // test empty elements nextLine = csvr.readNext(); assertEquals(3, nextLine.length); // test multiline quoted nextLine = csvr.readNext(); assertEquals(3, nextLine.length); // test quoted quote chars nextLine = csvr.readNext(); assertEquals("Glen \"The Man\" Smith", nextLine[0]); nextLine = csvr.readNext(); assertTrue(nextLine[0].equals("\"\"")); // check the tricky situation assertTrue(nextLine[1].equals("test")); // make sure we didn't ruin the next field.. nextLine = csvr.readNext(); assertEquals(4, nextLine.length); //test end of stream assertEquals(null, csvr.readNext()); } /** * Test parsing to a list. * * @throws IOException * if the reader fails. */ public void testParseAll() throws IOException { List allElements = csvr.readAll(); assertEquals(7, allElements.size()); } /** * Tests constructors with optional delimiters and optional quote char. * * @throws IOException if the reader fails. */ public void testOptionalConstructors() throws IOException { StringBuffer sb = new StringBuffer(); sb.append("a\tb\tc").append("\n"); // tab separated case sb.append("a\t'b\tb\tb'\tc").append("\n"); // single quoted elements CSVReader c = new CSVReader(new StringReader(sb.toString()), '\t', '\''); String[] nextLine = c.readNext(); assertEquals(3, nextLine.length); nextLine = c.readNext(); assertEquals(3, nextLine.length); } /** * Tests option to skip the first few lines of a file. * * @throws IOException if bad things happen */ public void testSkippingLines() throws IOException { StringBuffer sb = new StringBuffer(); sb.append("Skip this line\t with tab").append("\n"); // should skip this sb.append("And this line too").append("\n"); // and this sb.append("a\t'b\tb\tb'\tc").append("\n"); // single quoted elements CSVReader c = new CSVReader(new StringReader(sb.toString()), '\t', '\'', 2); String[] nextLine = c.readNext(); assertEquals(3, nextLine.length); assertEquals("a", nextLine[0]); } /** * Tests quotes in the middle of an element. * * @throws IOException if bad things happen */ public void testParsedLineWithInternalQuota() throws IOException { StringBuffer sb = new StringBuffer(); sb.append("a,123\"4\"567,c").append("\n");// a,123"4",c CSVReader c = new CSVReader(new StringReader(sb.toString())); String[] nextLine = c.readNext(); assertEquals(3, nextLine.length); System.out.println(nextLine[1]); assertEquals("123\"4\"567", nextLine[1]); } /** * The Test Runner for commandline use. * * @param args * no args required */ public static void main(String args[]) { junit.textui.TestRunner.run(CSVReaderTest.class); } } Helper class to write table data to a csv-file (comma separated values). /* Copyright (c) 2001-2009, The HSQL Development Group * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the HSQL Development Group nor the names of its * contributors may be used to endorse or promote products derived from this * software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG, * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStreamWriter; /** * helper class to write table data to a csv-file (comma separated values). * the first line in file is a list of fieldnames, all following lines * are data lines. * a descptiontion of file format can be found on: http://www.wotsit.org/ * usage: create a object using the constructor. call writeHeader * for writing the filename header then add data with writeData. * at the end close() closes the file. * *@author jeberle@users */ public class CSVWriter { private String newline = System.getProperty("line.separator"); private OutputStreamWriter writer = null; private int nbrCols = 0; private int nbrRows = 0; /** * constructor. * creates a csv file for writing data to it * @param file the file to write data to * @param encoding encoding to use or null (=defualt) */ public CSVWriter(File file, String encoding) throws IOException { if (encoding == null) { encoding = System.getProperty("file.encoding"); } FileOutputStream fout = new FileOutputStream(file); writer = new OutputStreamWriter(fout, encoding); } /** * writes the csv header (fieldnames). should be called after * construction one time. * @param header String[] with fieldnames */ public void writeHeader(String[] header) throws IOException { this.nbrCols = header.length; doWriteData(header); } /** * writes a data-record to the file. note that data[] must have * same number of elements as the header had. * * @param data data to write to csv-file */ public void writeData(String[] data) throws IOException { doWriteData(data); } /** * closes the csv file. */ public void close() throws IOException { this.writer.close(); } private void doWriteData(String[] values) throws IOException { for (int i = 0; i < values.length; i++) { if (i > 0) { this.writer.write(";"); } if (values[i] != null) { this.writer.write("\""); this.writer.write(this.toCsvValue(values[i])); this.writer.write("\""); } } this.writer.write(newline); this.nbrRows++; } private String toCsvValue(String str) { StringBuffer sb = new StringBuffer(); for (int i = 0; i < str.length(); i++) { char c = str.charAt(i); sb.append(c); switch (c) { case '"' : sb.append('"'); break; } } return sb.toString(); } }