Java tutorial
/* * Copyright 2012-2013 inBloom, Inc. and its affiliates. * * 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. */ package org.slc.sli.sample.transform; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.File; import java.io.FileInputStream; import java.io.FileReader; import java.io.FileWriter; import java.io.IOException; import java.io.InputStreamReader; import java.io.RandomAccessFile; import java.util.HashMap; import java.util.Map; import java.util.regex.Pattern; import org.apache.commons.csv.CSVParser; import org.apache.commons.csv.CSVStrategy; public class CcsCsvReader { private static Pattern commaAndSpaces = Pattern.compile("^[\\s,]*$"); private CSVParser csvParser; private Map<String, String> currentRecord; private String[] firstLine; private String copyright; private boolean containsCopyright; private String fileLocation; void setFileLocation(String fileLocation) throws IOException { this.fileLocation = fileLocation; } void setContainsCopyright(boolean containsCopyright) { this.containsCopyright = containsCopyright; } void load() throws IOException { File file = new File(fileLocation); file = removeEmptyLinesFromCsv(file); if (containsCopyright) { copyright = removeTrailingCharacters(tail(file), ','); file = removeLastLine(file); } InputStreamReader isReader = new InputStreamReader(new FileInputStream(file), "UTF-8"); csvParser = new CSVParser(isReader, CSVStrategy.EXCEL_STRATEGY); firstLine = csvParser.getLine(); getNextRecord(); } void getNextRecord() throws IOException { String[] line = csvParser.getLine(); if (line == null) { currentRecord = null; return; } Map<String, String> record = new HashMap<String, String>(); for (int i = 0; i < firstLine.length; i++) { record.put(firstLine[i], line[i]); } currentRecord = record; } Map<String, String> getCurrentRecord() { return currentRecord; } String getCopyright() { return copyright; } private String tail(File file) { try { RandomAccessFile fileHandler = new RandomAccessFile(file, "r"); long fileLength = file.length() - 1; long filePointer; for (filePointer = fileLength; filePointer != -1; filePointer--) { fileHandler.seek(filePointer); int readByte = fileHandler.readByte(); if (readByte == 0xA) { if (filePointer == fileLength) { continue; } else { break; } } else if (readByte == 0xD) { if (filePointer == fileLength - 1) { continue; } else { break; } } } String lastLine = fileHandler.readLine(); fileHandler.close(); return lastLine.substring(1); } catch (java.io.FileNotFoundException e) { e.printStackTrace(); return null; } catch (java.io.IOException e) { e.printStackTrace(); return null; } } private String removeTrailingCharacters(String s, char c) { int lastNonCommaIndex = -1; for (int i = s.length() - 1; i >= 0; i--) { if (s.charAt(i) != c) { lastNonCommaIndex = i; break; } } if (lastNonCommaIndex != -1) { return s.substring(0, lastNonCommaIndex + 1); } return ""; } private File removeLastLine(File fileIn) throws IOException { File tempFile = File.createTempFile("temp", "txt"); tempFile.deleteOnExit(); BufferedWriter writer = new BufferedWriter(new FileWriter(tempFile)); BufferedReader reader = new BufferedReader(new FileReader(fileIn)); String previousLine = reader.readLine(); if (previousLine != null) { for (;;) { String line = reader.readLine(); if (line == null) { break; } else { writer.write(previousLine); writer.write('\n'); previousLine = line; } } } reader.close(); writer.close(); return tempFile; } private File removeEmptyLinesFromCsv(File csvFileIn) throws IOException { File tempFile = File.createTempFile("temp", "txt"); tempFile.deleteOnExit(); BufferedWriter writer = new BufferedWriter(new FileWriter(tempFile)); BufferedReader reader = new BufferedReader(new FileReader(csvFileIn)); for (;;) { String line = reader.readLine(); if (line == null) { break; } else if ("".equals(line.trim())) { continue; } else if (!commaAndSpaces.matcher(line).matches()) { writer.write(line); writer.write('\n'); } } reader.close(); writer.close(); return tempFile; } }