Writes CSV (Comma Separated Value) files
/*------------------------------------------------------------------------------
Name: CSVWriter.java
Project: jutils.org
Comment: writes CSV (Comma Separated Value) files
Version: $Id: CSVWriter.java,v 1.2 2004/04/07 08:04:24 laurent Exp $
Author: Roedy Green roedy@mindprod.com, Heinrich Goetzger goetzger@gmx.net
------------------------------------------------------------------------------*/
import java.io.EOFException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.Writer;
/**
* Writes CSV (Comma Separated Value) files.
*
* This format is mainly used my Microsoft Word and Excel.
* Fields are separated by commas, and enclosed in
* quotes if they contain commas or quotes.
* Embedded quotes are doubled.
* Embedded spaces do not normally require surrounding quotes.
* The last field on the line is not followed by a comma.
* Null fields are represented by two commas in a row.
*
* @author copyright (c) 2002 Roedy Green Canadian Mind Products
* Roedy posted this code on Newsgroups:comp.lang.java.programmer on 27th March 2002.
*
* Heinrich added some stuff like comment ability and linewise working.
*
*/
public class CSVWriter {
/**
* Constructor
*
* @param pw PrintWriter where fields will be written.
* @param forceQuotes
* true if you want all fields surrounded in quotes,
* whether or not they contain commas, quotes or spaces.
* @param separator
* field separator character, usually ',' in North America,
* ';' in Europe and sometimes '\t' for tab.
* @param lineSeparator
* gives the delimiter for the line; is per default set to
* the system property 'line.separator'
*/
public CSVWriter(PrintWriter pw, boolean forceQuotes, char separator, String lineSeparator) {
this.pw = pw;
this.forceQuotes = forceQuotes;
this.separator = separator;
this.comment = "# ";
this.lineSeparator = lineSeparator;
} // end of CSVWriter
public CSVWriter(Writer w, boolean forceQuotes, char separator, String lineSeparator) {
this(new PrintWriter(w),forceQuotes,separator,lineSeparator);
}
/**
* Constructor with default field separator ','.
*
* @param pw PrintWriter where fields will be written.
*/
public CSVWriter(PrintWriter pw) {
this.pw = pw;
this.forceQuotes = false;
this.separator = ',';
this.comment = "# ";
this.lineSeparator = System.getProperty("line.separator");
} // end of CSVWriter
public CSVWriter(Writer w) {
this(new PrintWriter(w));
}
/**
* Constructor with default field separator ','.
*
* @param pw PrintWriter where fields will be written.
* @param comment Character used to start a comment line
*/
public CSVWriter(PrintWriter pw, char comment) {
this.pw = pw;
this.forceQuotes = false;
this.separator = ',';
this.comment = String.valueOf(comment) + " ";
this.lineSeparator = System.getProperty("line.separator");
} // end of CSVWriter
public CSVWriter(Writer w, char comment) {
this(new PrintWriter(w),comment);
}
/**
* PrintWriter where CSV fields will be written.
*/
PrintWriter pw;
/**
* true if you want all fields surrounded in quotes,
* whether or not they contain commas, quotes or spaces.
*/
boolean forceQuotes;
/*
* field separator character, usually ',' in North America,
* ';' in Europe and sometimes '\t' for tab.
*/
char separator;
/**
* true if there has was a field previously written to
* this line, meaning there is a comma pending to
* be written.
*/
boolean wasPreviousField = false;
/**
* Character to start a comment line with. May be '#' for example.
*/
String comment;
/**
* Line separator.
*/
String lineSeparator;
/**
* Writes a single coment line to the file given by the <code>text</code>.
* This is the text leaded by the <code>comment char + " "</code>, given in the constructor.
* @param text contains the comment text.
*/
public void writeCommentln(String text) {
if (wasPreviousField) writeln(); // close open line since we need to start a new one for comment
pw.print(comment);
//wasPreviousField = false; // to prevent a comma after the comment sign
write(text);
writeln();
} // end of writeComentln
/**
* Writes a single value in a line suited by a newline to the file given by the <code>token</code>.
* @param token contains the value.
*/
public void writeln(String token) {
write(token);
writeln();
} // end of writeln
/**
* Writes a new line in the CVS output file to demark the end of record.
*/
public void writeln() {
/* don't bother to write last pending comma on the line */
wasPreviousField = false;
pw.print(lineSeparator);
} // end of writeln
/**
* Writes a single line of comma separated values from the array given by <code>line</code>.
* @param line containig an array of tokens.
*/
public void writeln(String[] line) {
for(int ii=0; ii < line.length; ii++) {
write(line[ii]);
} // end of for
writeln(); // write newLine
} // end of writeln
/**
* Write one csv field to the file, followed by a separator
* unless it is the last field on the line. Lead and trailing
* blanks will be removed.
*
* @param s The string to write. Any additional quotes or
* embedded quotes will be provided by write.
*/
public void write(String s) {
if ( wasPreviousField ) {
pw.print(separator);
}
if ( s == null ) {
pw.print("");
return;
} // end of if s == null
s = s.trim();
if ( s.indexOf('\"') >= 0 ) {
/* worst case, needs surrounding quotes and internal quotes doubled */
pw.print ('\"');
for ( int i=0; i<s.length(); i++ ) {
char c = s.charAt(i);
if ( c == '\"' ) {
pw.print("\"\"");
} else {
pw.print(c);
}
}
pw.print ('\"');
// end of if \"
} else if ( s.indexOf('\n') >=0 ) {
// bad case as well: having a new line in the token: \n
pw.print ('\"');
for ( int i=0; i<s.length(); i++ ) {
char c = s.charAt(i);
if ( c == '\n' ) {
pw.print("\\n");
} else {
pw.print(c);
}
}
pw.print ('\"');
// end of if \n
} else if ( forceQuotes || s.indexOf(separator) >= 0 ) {
/* need surrounding quotes */
pw.print ('\"');
pw.print(s);
pw.print ('\"');
} else {
/* ordinary case, no surrounding quotes needed */
pw.print(s);
}
/* make a note to print trailing comma later */
wasPreviousField = true;
} // end of write
/**
* Close the PrintWriter.
*/
public void close() {
if ( pw != null ) {
pw.close();
pw = null;
} // end of if
} // end of close
/**
* Test driver
*
* @param args [0]: The name of the file.
*/
static public void main(String[] args) {
try {
// write out a test file
PrintWriter pw = new PrintWriter( new FileWriter(args[0]));
CSVWriter csv = new CSVWriter(pw, false, ',', System.getProperty("line.separator") );
csv.writeCommentln("This is a test csv-file: '" + args[0] + "'");
csv.write("abc");
csv.write("def");
csv.write("g h i");
csv.write("jk,l");
csv.write("m\"n\'o ");
csv.writeln();
csv.write("m\"n\'o ");
csv.write(" ");
csv.write("a");
csv.write("x,y,z");
csv.write("x;y;z");
csv.writeln();
csv.writeln(new String[] {"This", "is", "an", "array."});
csv.close();
} catch ( IOException e ) {
e.printStackTrace();
System.out.println(e.getMessage());
}
} // end main
} // end CSVWriter
// end of file
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