Soderer.de (private Homepage)

Diese Klasse kann CSV Daten aus Datein und Streams lesen. Dabei werden beliebige Trennzeichen (nicht nur Komma und Semikolon) unterstützt, sowie Textkennzeichen jeder Art oder ohne. Es ist auch möglich das Textkennzeichen innerhalb der Texte zu escapen und Zeilenbrüche darin zu verwenden (default) oder dies zu unterbinden. Sind nicht alle Zeilen mit der gleichen Anzahl an Daten gefüllt kann dies ignoriert oder unterbunden werden (default):

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import java.io.BufferedReader; import java.io.ByteArrayInputStream; import java.io.Closeable; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.nio.charset.Charset; import java.util.ArrayList; import java.util.List; /** * The Class CsvReader. */ public class CsvReader implements Closeable { /** UTF-8 BOM (Byte Order Mark) character for readers. */ public static final char BOM_UTF_8_CHAR = (char) 65279; /** UTF-8 BOM (Byte Order Mark) at data start (EF BB BF, "ï»¿"). */ public static final byte[] BOM_UTF_8 = new byte[]{(byte) 0xEF, (byte) 0xBB, (byte) 0xBF}; /** UTF-16 BOM (Byte Order Mark) big endian at data start (FE FF, "þÿ"). */ public static final byte[] BOM_UTF_16_BIG_ENDIAN = new byte[]{(byte) 0xFE, (byte) 0xFF}; /** UTF-16 BOM (Byte Order Mark) low endian at data start (FF FE, "ÿþ"). */ public static final byte[] BOM_UTF_16_LOW_ENDIAN = new byte[]{(byte) 0xFF, (byte) 0xFE}; /** The Constant DEFAULT_ENCODING. */ public static final String DEFAULT_ENCODING = "UTF-8"; /** The Constant DEFAULT_SEPARATOR. */ public static final char DEFAULT_SEPARATOR = ','; /** The Constant DEFAULT_STRING_QUOTE. */ public static final char DEFAULT_STRING_QUOTE = '"'; /** Mandatory separating charactor. */ private char separator; /** Character for stringquotes: if set to null, no quoting will be done. */ private char stringQuote; /** * Character to escape the stringquote character within quoted strings. * By default this is the stringquote character itself, so it is doubled in quoted string, but may also be a backslash '\'. */ private char stringQuoteEscapeCharacter; /** Since stringQuote is a simple char this activates or deactivates the quoting. */ private boolean useStringQuote; /** Inputstream for data. */ private InputStream inputStream; /** Encoding of data. */ private Charset encoding; /** Allow linebreaks in data texts without the effect of a new data set line. */ private boolean lineBreakInDataAllowed = true; /** Allow double stringquotes to use it as a character in data text. */ private boolean escapedStringQuoteInDataAllowed = true; /** If a single read was done, it is impossible to make a full read at once with readAll(). */ private boolean singleReadStarted = false; /** Number of columns expected (set by first read line). */ private int numberOfColumns = -1; /** Data reader. */ private BufferedReader inputReader = null; /** Number of lines read until now. */ private int readLines = 0; /** Number of chracters read until now. */ private int readCharacters = 0; /** Allow lines with less than the expected number of data entries per line. */ private boolean fillMissingTrailingColumnsWithNull = false; /** * CSV Reader derived constructor. * * @param inputStream the input stream */ public CsvReader(InputStream inputStream) { this(inputStream, Charset.forName(DEFAULT_ENCODING), DEFAULT_SEPARATOR, DEFAULT_STRING_QUOTE); } /** * CSV Reader derived constructor. * * @param inputStream the input stream * @param encoding the encoding */ public CsvReader(InputStream inputStream, String encoding) { this(inputStream, Charset.forName(encoding), DEFAULT_SEPARATOR, DEFAULT_STRING_QUOTE); } /** * CSV Reader derived constructor. * * @param inputStream the input stream * @param encoding the encoding */ public CsvReader(InputStream inputStream, Charset encoding) { this(inputStream, encoding, DEFAULT_SEPARATOR, DEFAULT_STRING_QUOTE); } /** * CSV Reader derived constructor. * * @param inputStream the input stream * @param separator the separator */ public CsvReader(InputStream inputStream, char separator) { this(inputStream, Charset.forName(DEFAULT_ENCODING), separator, DEFAULT_STRING_QUOTE); } /** * CSV Reader derived constructor. * * @param inputStream the input stream * @param encoding the encoding * @param separator the separator */ public CsvReader(InputStream inputStream, String encoding, char separator) { this(inputStream, Charset.forName(encoding), separator, DEFAULT_STRING_QUOTE); } /** * CSV Reader derived constructor. * * @param inputStream the input stream * @param encoding the encoding * @param separator the separator */ public CsvReader(InputStream inputStream, Charset encoding, char separator) { this(inputStream, encoding, separator, DEFAULT_STRING_QUOTE); } /** * CSV Reader derived constructor. * * @param inputStream the input stream * @param separator the separator * @param stringQuote the string quote */ public CsvReader(InputStream inputStream, char separator, Character stringQuote) { this(inputStream, Charset.forName(DEFAULT_ENCODING), separator, stringQuote); } /** * CSV Reader derived constructor. * * @param inputStream the input stream * @param encoding the encoding * @param separator the separator * @param stringQuote the string quote */ public CsvReader(InputStream inputStream, String encoding, char separator, Character stringQuote) { this(inputStream, Charset.forName(encoding), separator, stringQuote); } /** * CSV Reader main constructor. * * @param inputStream the input stream * @param encoding the encoding * @param separator the separator * @param stringQuote the string quote */ public CsvReader(InputStream inputStream, Charset encoding, char separator, Character stringQuote) { this.inputStream = inputStream; this.encoding = encoding; this.separator = separator; if (stringQuote != null) { this.stringQuote = stringQuote; stringQuoteEscapeCharacter = stringQuote; this.useStringQuote = true; } else { this.useStringQuote = false; } if (this.encoding == null) { throw new IllegalArgumentException("Encoding is null"); } else if (this.inputStream == null) { throw new IllegalArgumentException("InputStream is null"); } else if (anyCharsAreEqual(this.separator, '\r', '\n')) { throw new IllegalArgumentException("Separator '" + this.separator + "' is invalid"); } else if (useStringQuote && anyCharsAreEqual(this.separator, this.stringQuote, '\r', '\n')) { throw new IllegalArgumentException("Stringquote '" + this.stringQuote + "' is invalid"); } } /** * Getter for property fillMissingTrailingColumnsWithNull. * * @return true, if is fill missing trailing columns with null */ public boolean isFillMissingTrailingColumnsWithNull() { return fillMissingTrailingColumnsWithNull; } /** * Setter for property fillMissingTrailingColumnsWithNull. * * @param fillMissingTrailingColumnsWithNull the new fill missing trailing columns with null */ public void setFillMissingTrailingColumnsWithNull(boolean fillMissingTrailingColumnsWithNull) { this.fillMissingTrailingColumnsWithNull = fillMissingTrailingColumnsWithNull; } /** * Setter for property stringQuoteEscapeCharacter. * Character to escape the stringquote character within quoted strings. * By default this is the stringquote character itself, so it is doubled in quoted string, but may also be a backslash '\'. * * @param stringQuoteEscapeCharacter the new fill missing trailing columns with null */ public void setStringQuoteEscapeCharacter(char stringQuoteEscapeCharacter) { this.stringQuoteEscapeCharacter = stringQuoteEscapeCharacter; if (useStringQuote && anyCharsAreEqual(this.separator, this.stringQuote, '\r', '\n', stringQuoteEscapeCharacter)) { throw new IllegalArgumentException("Stringquote escape character '" + this.stringQuoteEscapeCharacter + "' is invalid"); } } /** * Read the next line of csv data. * * @return the list * @throws IOException Signals that an I/O exception has occurred. * @throws CsvDataException the csv data exception */ public List<String> readNextCsvLine() throws IOException, CsvDataException { if (inputReader == null) { if (inputStream == null) { throw new IllegalStateException("CsvReader is already closed"); } inputReader = new BufferedReader(new InputStreamReader(inputStream, encoding)); } readLines++; singleReadStarted = true; List<String> returnList = new ArrayList<String>(); StringBuilder nextValue = new StringBuilder(); boolean insideString = false; int nextCharInt = -1; int previousCharInt = -1; while ((nextCharInt = inputReader.read()) != -1) { // Check for UTF-8 BOM at data start if (readCharacters == 0 && encoding == Charset.forName("UTF-8") && nextCharInt == BOM_UTF_8_CHAR) { continue; } readCharacters++; char nextChar = (char) nextCharInt; if (useStringQuote && nextChar == stringQuote) { if (stringQuoteEscapeCharacter != stringQuote) { if (previousCharInt != stringQuoteEscapeCharacter) { insideString = !insideString; } } else { insideString = !insideString; } nextValue.append(nextChar); } else if (!insideString) { if (nextChar == '\r' || nextChar == '\n') { if (nextValue.length() > 0 || previousCharInt == separator) { returnList.add(parseValue(nextValue.toString())); } if (returnList.size() > 0) { if (numberOfColumns != -1 && numberOfColumns != returnList.size()) { if (numberOfColumns > returnList.size() && fillMissingTrailingColumnsWithNull) { while (returnList.size() < numberOfColumns) { returnList.add(null); } } else { throw new CsvDataException("Inconsistent number of values in line " + readLines + " (expected: " + numberOfColumns + " actually: " + returnList.size() + ")", readLines); } } numberOfColumns = returnList.size(); return returnList; } } else if (nextChar == separator) { returnList.add(parseValue(nextValue.toString())); nextValue = new StringBuilder(); } else { nextValue.append(nextChar); } } else { // insideString if ((nextChar == '\r' || nextChar == '\n') && !lineBreakInDataAllowed) { throw new CsvDataException("Not allowed linebreak in data in line " + readLines, readLines); } else { nextValue.append(nextChar); } } previousCharInt = nextCharInt; } if (insideString) { close(); throw new IOException("Unexpected end of data after quoted csv-value was started"); } else { if (nextValue.length() > 0 || previousCharInt == separator) { returnList.add(parseValue(nextValue.toString())); } if (returnList.size() > 0) { if (numberOfColumns != -1 && numberOfColumns != returnList.size()) { if (numberOfColumns > returnList.size() && fillMissingTrailingColumnsWithNull) { while (returnList.size() < numberOfColumns) { returnList.add(null); } } else { throw new CsvDataException("Inconsistent number of values in line " + readLines + " (expected: " + numberOfColumns + " actually: " + returnList.size() + ")", readLines); } } numberOfColumns = returnList.size(); return returnList; } else { close(); return null; } } } /** * Read all csv data at once. This can only be done before readNextCsvLine() was called for the first time * * @return the list * @throws IOException Signals that an I/O exception has occurred. * @throws CsvDataException the csv data exception */ public List<List<String>> readAll() throws IOException, CsvDataException { if (singleReadStarted) { throw new IllegalStateException("Single readNextCsvLine was called before readAll"); } try { List<List<String>> csvValues = new ArrayList<List<String>>(); List<String> lineValues; while ((lineValues = readNextCsvLine()) != null) { csvValues.add(lineValues); } return csvValues; } finally { close(); } } /** * Parse a single value to applicate allowed double stringquotes. * * @param rawValue the raw value * @return the string * @throws CsvDataException the csv data exception */ private String parseValue(String rawValue) throws CsvDataException { String returnValue = rawValue; String stringQuoteString = Character.toString(stringQuote); if (isNotEmpty(returnValue)) { if (useStringQuote) { if (returnValue.contains(stringQuoteString)) { returnValue = returnValue.trim(); } if (returnValue.charAt(0) == stringQuote && returnValue.charAt(returnValue.length() - 1) == stringQuote) { returnValue = returnValue.substring(1, returnValue.length() - 1); returnValue = returnValue.replace(stringQuoteEscapeCharacter + stringQuoteString, stringQuoteString); } } returnValue = returnValue.replace("\r\n", "\n").replace('\r', '\n'); } if (!escapedStringQuoteInDataAllowed && returnValue.indexOf(stringQuote) >= 0) { throw new CsvDataException("Not allowed stringquote in data in line " + readLines, readLines); } return returnValue; } /** * CLose this reader and its underlying stream. */ @Override public void close() { closeQuietly(inputReader); inputReader = null; closeQuietly(inputStream); inputStream = null; } /** * Get lines read until now. * * @return the read lines */ public int getReadLines() { return readLines; } /** * Get characters read until now. * * @return the read chracters */ public int getReadChracters() { return readCharacters; } /** * Getter for property lineBreakInDataAllowed. * * @return true, if is line break in data allowed */ public boolean isLineBreakInDataAllowed() { return lineBreakInDataAllowed; } /** * Setter for property lineBreakInDataAllowed. * * @param lineBreakInDataAllowed the new line break in data allowed */ public void setLineBreakInDataAllowed(boolean lineBreakInDataAllowed) { this.lineBreakInDataAllowed = lineBreakInDataAllowed; } /** * Getter for property escapedStringQuoteInDataAllowed. * * @return true, if is escaped string quote in data allowed */ public boolean isEscapedStringQuoteInDataAllowed() { return escapedStringQuoteInDataAllowed; } /** * Setter for property escapedStringQuoteInDataAllowed. * * @param escapedStringQuoteInDataAllowed the new escaped string quote in data allowed */ public void setEscapedStringQuoteInDataAllowed(boolean escapedStringQuoteInDataAllowed) { this.escapedStringQuoteInDataAllowed = escapedStringQuoteInDataAllowed; } /** * This method reads the stream to the end and counts all csv value lines, * which can be less than the absolute linebreak count of the stream for the reason of quoted linebreaks. * The result also contains the first line, which may consist of columnheaders. * * @return the csv line count * @throws IOException Signals that an I/O exception has occurred. * @throws CsvDataException the csv data exception */ public int getCsvLineCount() throws IOException, CsvDataException { if (singleReadStarted) { throw new IllegalStateException("Single readNextCsvLine was called before getCsvLineCount"); } try { int csvLineCount = 0; while (readNextCsvLine() != null) { csvLineCount++; } return csvLineCount; } finally { close(); } } /** * Parse a single csv data line for data entries. * * @param separator the separator * @param stringQuote the string quote * @param csvLine the csv line * @return the list * @throws Exception the exception */ public static List<String> parseCsvLine(char separator, Character stringQuote, String csvLine) throws Exception { CsvReader reader = null; try { reader = new CsvReader(new ByteArrayInputStream(csvLine.getBytes("UTF-8")), "UTF-8", separator, stringQuote); List<List<String>> fullData = reader.readAll(); if (fullData.size() != 1) { throw new Exception("Too many csv lines in data"); } else { return fullData.get(0); } } catch (CsvDataException e) { throw e; } finally { if (reader != null) { reader.close(); } } } /** * Check if any characters in a list are equal. * * @param values the values * @return true, if successful */ private static boolean anyCharsAreEqual(char... values) { for (int i = 0; i < values.length; i++) { for (int j = i + 1; j < values.length; j++) { if (values[i] == values[j]) { return true; } } } return false; } /** * Check if String value is not null and has a length greater than 0. * * @param value the value * @return true, if is not empty */ private static boolean isNotEmpty(String value) { return value != null && value.length() > 0; } /** * Close a Closable item and ignore any Exception thrown by its close method. * * @param closeableItem the closeable item */ private static void closeQuietly(Closeable closeableItem) { if (closeableItem != null) { try { closeableItem.close(); } catch (IOException e) { // Do nothing } } } }

Schreiben von CSV Daten in Dateien und Streams:

Diese Klasse kann CSV Daten in Datein und Streams schreiben. Dabei werden beliebige Trennzeichen (nicht nur Komma und Semikolon) unterstützt, sowie Textkennzeichen jeder Art oder ohne.

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import java.io.BufferedWriter; import java.io.Closeable; import java.io.IOException; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.Writer; import java.nio.charset.Charset; import java.util.Arrays; import java.util.List; /** * The Class CsvWriter. */ public class CsvWriter extends Writer { /** Default output encoding. */ public static final String DEFAULT_ENCODING = "UTF-8"; /** Default output separator. */ public static final char DEFAULT_SEPARATOR = ','; /** Default output stringquote. */ public static final char DEFAULT_STRING_QUOTE = '"'; /** Default output linebreak. */ public static final String DEFAULT_LINEBREAK = "\n"; /** Current output separator. */ private char separator; /** Current output separator as string. */ private String separatorString; /** Current output string quote. */ private char stringQuote; /** * Character to escape the stringquote character within quoted strings. * By default this is the stringquote character itself, so it is doubled in quoted string, but may also be a backslash '\'. */ private char stringQuoteEscapeCharacter; /** Current output string quote as string for internal use. */ private String stringQuoteString; /** Current output string quote two times for internal use. */ private String escapedStringQuoteString; /** Currently use the string quote. */ private boolean useStringQuote; /** Current output linebreak. */ private String lineBreak; /** Output stream. */ private OutputStream outputStream; /** Output encoding. */ private Charset encoding; /** Always quote all data entries. */ private boolean alwaysQuote = false; /** Always quote texts or only quote them when they contain linebreaks or the separator character. */ private boolean quoteAllStrings = false; /** Lines written until now. */ private int writtenLines = 0; /** Number of columns to write, set by first line written. */ private int numberOfColumns = -1; /** Output writer. */ private BufferedWriter outputWriter = null; /** * CSV Writer derived constructor. * * @param outputStream the output stream */ public CsvWriter(OutputStream outputStream) { this(outputStream, Charset.forName(DEFAULT_ENCODING), DEFAULT_SEPARATOR, DEFAULT_STRING_QUOTE, DEFAULT_LINEBREAK); } /** * CSV Writer derived constructor. * * @param outputStream the output stream * @param encoding the encoding */ public CsvWriter(OutputStream outputStream, String encoding) { this(outputStream, Charset.forName(encoding), DEFAULT_SEPARATOR, DEFAULT_STRING_QUOTE, DEFAULT_LINEBREAK); } /** * CSV Writer derived constructor. * * @param outputStream the output stream * @param encoding the encoding */ public CsvWriter(OutputStream outputStream, Charset encoding) { this(outputStream, encoding, DEFAULT_SEPARATOR, DEFAULT_STRING_QUOTE, DEFAULT_LINEBREAK); } /** * CSV Writer derived constructor. * * @param outputStream the output stream * @param separator the separator */ public CsvWriter(OutputStream outputStream, char separator) { this(outputStream, Charset.forName(DEFAULT_ENCODING), separator, DEFAULT_STRING_QUOTE, DEFAULT_LINEBREAK); } /** * CSV Writer derived constructor. * * @param outputStream the output stream * @param encoding the encoding * @param separator the separator */ public CsvWriter(OutputStream outputStream, String encoding, char separator) { this(outputStream, Charset.forName(encoding), separator, DEFAULT_STRING_QUOTE, DEFAULT_LINEBREAK); } /** * CSV Writer derived constructor. * * @param outputStream the output stream * @param encoding the encoding * @param separator the separator */ public CsvWriter(OutputStream outputStream, Charset encoding, char separator) { this(outputStream, encoding, separator, DEFAULT_STRING_QUOTE, DEFAULT_LINEBREAK); } /** * CSV Writer derived constructor. * * @param outputStream the output stream * @param separator the separator * @param stringQuote the string quote */ public CsvWriter(OutputStream outputStream, char separator, Character stringQuote) { this(outputStream, Charset.forName(DEFAULT_ENCODING), separator, stringQuote, DEFAULT_LINEBREAK); } /** * CSV Writer derived constructor. * * @param outputStream the output stream * @param separator the separator * @param stringQuote the string quote * @param lineBreak the line break */ public CsvWriter(OutputStream outputStream, char separator, Character stringQuote, String lineBreak) { this(outputStream, Charset.forName(DEFAULT_ENCODING), separator, stringQuote, lineBreak); } /** * CSV Writer derived constructor. * * @param outputStream the output stream * @param encoding the encoding * @param separator the separator * @param stringQuote the string quote */ public CsvWriter(OutputStream outputStream, String encoding, char separator, Character stringQuote) { this(outputStream, isBlank(encoding) ? Charset.forName(DEFAULT_ENCODING) : Charset.forName(encoding), separator, stringQuote == null ? DEFAULT_STRING_QUOTE : stringQuote, DEFAULT_LINEBREAK); } /** * CSV Writer main constructor. * * @param outputStream the output stream * @param encoding the encoding * @param separator the separator * @param stringQuote the string quote * @param lineBreak the line break */ public CsvWriter(OutputStream outputStream, Charset encoding, char separator, Character stringQuote, String lineBreak) { this.outputStream = outputStream; this.encoding = encoding; this.separator = separator; separatorString = Character.toString(separator); this.lineBreak = lineBreak; if (stringQuote != null) { this.stringQuote = stringQuote; stringQuoteEscapeCharacter = stringQuote; stringQuoteString = Character.toString(stringQuote); escapedStringQuoteString = stringQuoteEscapeCharacter + stringQuoteString; this.useStringQuote = true; } else { this.useStringQuote = false; } if (this.encoding == null) { throw new IllegalArgumentException("Encoding is null"); } else if (this.outputStream == null) { throw new IllegalArgumentException("OutputStream is null"); } else if (anyCharsAreEqual(this.separator, '\r', '\n')) { throw new IllegalArgumentException("Separator '" + this.separator + "' is invalid"); } else if (useStringQuote && anyCharsAreEqual(this.separator, this.stringQuote, '\r', '\n')) { throw new IllegalArgumentException("Stringquote '" + this.stringQuote + "' is invalid"); } else if (!this.lineBreak.equals("\r") && !this.lineBreak.equals("\n") && !this.lineBreak.equals("\r\n")) { throw new IllegalArgumentException("Given linebreak is invalid"); } } /** * Getter for property alwaysQuote. * * @return true, if is always quote */ public boolean isAlwaysQuote() { return alwaysQuote; } /** * Setter for property alwaysQuote. * * @param alwaysQuote the new always quote */ public void setAlwaysQuote(boolean alwaysQuote) { this.alwaysQuote = alwaysQuote; if (alwaysQuote) { quoteAllStrings = false; } } /** * Getter for property quoteAllStrings. * * @return true, if is quote all strings */ public boolean isQuoteAllStrings() { return quoteAllStrings; } /** * Setter for property quoteAllStrings. * * @param quoteAllStrings the new quote all strings */ public void setQuoteAllStrings(boolean quoteAllStrings) { this.quoteAllStrings = quoteAllStrings; if (quoteAllStrings) { alwaysQuote = false; } } /** * Setter for property stringQuoteEscapeCharacter. * Character to escape the stringquote character within quoted strings. * By default this is the stringquote character itself, so it is doubled in quoted string, but may also be a backslash '\'. * * @param stringQuoteEscapeCharacter the new fill missing trailing columns with null */ public void setStringQuoteEscapeCharacter(char stringQuoteEscapeCharacter) { this.stringQuoteEscapeCharacter = stringQuoteEscapeCharacter; if (useStringQuote && anyCharsAreEqual(this.separator, this.stringQuote, '\r', '\n', stringQuoteEscapeCharacter)) { throw new IllegalArgumentException("Stringquote escape character '" + this.stringQuoteEscapeCharacter + "' is invalid"); } escapedStringQuoteString = stringQuoteEscapeCharacter + stringQuoteString; } /** * Write a single line of data entries. * * @param values the values * @throws Exception the exception */ public void writeValues(Object... values) throws Exception { writeValues(Arrays.asList(values)); } /** * Write a single line of data entries. * * @param values the values * @throws CsvDataException the csv data exception * @throws IOException Signals that an I/O exception has occurred. */ public void writeValues(List<? extends Object> values) throws CsvDataException, IOException { if (numberOfColumns != -1 && (values == null || numberOfColumns != values.size())) { throw new CsvDataException("Inconsistent number of values after " + writtenLines + " written lines (expected: " + numberOfColumns + " was: " + (values == null ? "null" : values.size()) + ")", writtenLines); } if (outputWriter == null) { if (outputStream == null) { throw new IllegalStateException("CsvWriter is already closed"); } outputWriter = new BufferedWriter(new OutputStreamWriter(outputStream, encoding)); } boolean isFirst = true; for (Object value : values) { if (!isFirst) { outputWriter.write(separator); } isFirst = false; outputWriter.write(escapeValue(value)); } outputWriter.write(lineBreak); writtenLines++; numberOfColumns = values.size(); } /** * Write a full set of lines of data entries. * * @param valueLines the value lines * @throws Exception the exception */ public void writeAll(List<List<? extends Object>> valueLines) throws Exception { for (List<? extends Object> valuesOfLine : valueLines) { writeValues(valuesOfLine); } } /** * Escape a single data entry using stringquotes as configured. * * @param value the value * @return the string * @throws CsvDataException the csv data exception */ private String escapeValue(Object value) throws CsvDataException { String valueString = ""; if (value != null) { valueString = value.toString(); } if (alwaysQuote || (quoteAllStrings && value instanceof String) || valueString.contains(separatorString) || valueString.contains("\r") || valueString.contains("\n") || (useStringQuote && valueString.contains(stringQuoteString))) { if (!useStringQuote) { throw new CsvDataException("StringQuote was deactivated but is needed for csv-value after " + writtenLines + " written lines", writtenLines); } else { StringBuilder escapedValue = new StringBuilder(); escapedValue.append(stringQuote); escapedValue.append(valueString.replace(stringQuoteString, escapedStringQuoteString)); escapedValue.append(stringQuote); return escapedValue.toString(); } } else { return valueString; } } /** * Close this writer and its underlying stream. */ @Override public void close() { closeQuietly(outputWriter); outputWriter = null; closeQuietly(outputStream); outputStream = null; } /** * Get number of lines written until now. * * @return the written lines */ public int getWrittenLines() { return writtenLines; } /** * Not supported method to write data (must implement for writer interface). * * @param cbuf the cbuf * @param off the off * @param len the len * @throws IOException Signals that an I/O exception has occurred. */ @Override public void write(char[] cbuf, int off, int len) throws IOException { throw new IOException("Write by offset and length is not supported by " + getClass().getSimpleName()); } /** * Flush buffered data. * * @throws IOException Signals that an I/O exception has occurred. */ @Override public void flush() throws IOException { if (outputWriter != null) { outputWriter.flush(); } } /** * Create a single csv line. * * @param separator the separator * @param stringQuote the string quote * @param values the values * @return the csv line */ public static String getCsvLine(char separator, Character stringQuote, List<? extends Object> values) { return getCsvLine(separator, stringQuote, values.toArray()); } /** * Create a single csv line. * * @param separator the separator * @param stringQuote the string quote * @param values the values * @return the csv line */ public static String getCsvLine(char separator, Character stringQuote, Object... values) { StringBuilder returnValue = new StringBuilder(); String separatorString = Character.toString(separator); String stringQuoteString = stringQuote == null ? "" : Character.toString(stringQuote); String doubleStringQuoteString = stringQuoteString + stringQuoteString; if (values != null) { for (Object value : values) { if (returnValue.length() > 0) { returnValue.append(separator); } if (value != null) { String valueString = value.toString(); if (valueString.contains(separatorString) || valueString.contains("\r") || valueString.contains("\n") || valueString.contains(stringQuoteString)) { returnValue.append(stringQuoteString); returnValue.append(valueString.replace(stringQuoteString, doubleStringQuoteString)); returnValue.append(stringQuoteString); } else { returnValue.append(valueString); } } } } return returnValue.toString(); } /** * Check if any characters in a list are equal. * * @param values the values * @return true, if successful */ private static boolean anyCharsAreEqual(char... values) { for (int i = 0; i < values.length; i++) { for (int j = i + 1; j < values.length; j++) { if (values[i] == values[j]) { return true; } } } return false; } /** * Check if String value is null or contains only whitespace characters. * * @param value the value * @return true, if is blank */ private static boolean isBlank(String value) { return value == null || value.trim().length() == 0; } /** * Close a Closable item and ignore any Exception thrown by its close method. * * @param closeableItem the closeable item */ private static void closeQuietly(Closeable closeableItem) { if (closeableItem != null) { try { closeableItem.close(); } catch (IOException e) { // Do nothing } } } }

CSV-Reader und CSV-Writer

Lesen von CSV Daten aus Dateien und Streams:

Schreiben von CSV Daten in Dateien und Streams: