java解析DBF源码，修改之后的

/* DBFWriter Class for defining a DBF structure and addin data to that structure and finally writing it to an OutputStream. This file is part of JavaDBF packege. author: anil@linuxense.com license: LGPL (http://www.gnu.org/copyleft/lesser.html) $Id: DBFWriter.java,v 1.9 2004/03/31 10:57:16 anil Exp $ */ package dbf; import java.io.*; import java.util.*; /** An object of this class can create a DBF file. Create an object, <br> then define fields by creating DBFField objects and<br> add them to the DBFWriter object<br> add records using the addRecord() method and then<br> call write() method. */ public class DBFWriter extends DBFBase { /* other class variables */ DBFHeader header; @SuppressWarnings("unchecked") Vector v_records = new Vector(); int recordCount = 0; RandomAccessFile raf = null; /* Open and append records to an existing DBF */ boolean appendMode = false; /** Creates an empty Object. */ public DBFWriter() { this.header = new DBFHeader(); } /** Creates a DBFWriter which can append to records to an existing DBF file. @param dbfFile. The file passed in shouls be a valid DBF file. @exception Throws DBFException if the passed in file does exist but not a valid DBF file, or if an IO error occurs. */ public DBFWriter( File dbfFile) throws DBFException { try { this.raf = new RandomAccessFile( dbfFile, "rw"); /* before proceeding check whether the passed in File object is an empty/non-existent file or not. */ if( !dbfFile.exists() || dbfFile.length() == 0) { this.header = new DBFHeader(); return; } header = new DBFHeader(); this.header.read( raf); /* position file pointer at the end of the raf */ this.raf.seek( this.raf.length()-1 /* to ignore the END_OF_DATA byte at EoF */); } catch( FileNotFoundException e) { throw new DBFException( "Specified file is not found. " + e.getMessage()); } catch( IOException e) { throw new DBFException( e.getMessage() + " while reading header"); } this.recordCount = this.header.numberOfRecords; } /** Sets fields. */ public void setFields( DBFField[] fields) throws DBFException { if( this.header.fieldArray != null) { throw new DBFException( "Fields has already been set"); } if( fields == null || fields.length == 0) { throw new DBFException( "Should have at least one field"); } for( int i=0; i<fields.length; i++) { if( fields[i] == null) { throw new DBFException( "Field " + (i+1) + " is null"); } } this.header.fieldArray = fields; try { if( this.raf != null && this.raf.length() == 0) { /* this is a new/non-existent file. So write header before proceeding */ this.header.write( this.raf); } } catch( IOException e) { throw new DBFException( "Error accesing file"); } } /** Add a record. */ @SuppressWarnings("unchecked") public void addRecord( Object[] values) throws DBFException { if( this.header.fieldArray == null) { throw new DBFException( "Fields should be set before adding records"); } if( values == null) { throw new DBFException( "Null cannot be added as row"); } if( values.length != this.header.fieldArray.length) { throw new DBFException( "Invalid record. Invalid number of fields in row"); } for( int i=0; i<this.header.fieldArray.length; i++) { if( values[i] == null) { continue; } switch( this.header.fieldArray[i].getDataType()) { case 'C': if( !(values[i] instanceof String)) { throw new DBFException( "Invalid value for field " + i); } break; case 'L': if( !( values[i] instanceof Boolean)) { throw new DBFException( "Invalid value for field " + i); } break; case 'N': if( !( values[i] instanceof Double)) { throw new DBFException( "Invalid value for field " + i); } break; case 'D': if( !( values[i] instanceof Date)) { throw new DBFException( "Invalid value for field " + i); } break; case 'F': if( !(values[i] instanceof Double)) { throw new DBFException( "Invalid value for field " + i); } break; } } if( this.raf == null) { v_records.addElement( values); } else { try { writeRecord( this.raf, values); this.recordCount++; } catch( IOException e) { throw new DBFException( "Error occured while writing record. " + e.getMessage()); } } } /** Writes the set data to the OutputStream. */ public void write( OutputStream out) throws DBFException { try { if( this.raf == null) { DataOutputStream outStream = new DataOutputStream( out); this.header.numberOfRecords = v_records.size(); this.header.write( outStream); /* Now write all the records */ int t_recCount = v_records.size(); for( int i=0; i<t_recCount; i++) { /* iterate through records */ Object[] t_values = (Object[])v_records.elementAt( i); writeRecord( outStream, t_values); } outStream.write( END_OF_DATA); outStream.flush(); } else { /* everything is written already. just update the header for record count and the END_OF_DATA mark */ this.header.numberOfRecords = this.recordCount; this.raf.seek( 0); this.header.write( this.raf); this.raf.seek( raf.length()); this.raf.writeByte( END_OF_DATA); this.raf.close(); } } catch( IOException e) { throw new DBFException( e.getMessage()); } } public void write() throws DBFException { this.write( null); } private void writeRecord( DataOutput dataOutput, Object []objectArray) throws IOException { dataOutput.write( (byte)' '); for( int j=0; j<this.header.fieldArray.length; j++) { /* iterate throught fields */ switch( this.header.fieldArray[j].getDataType()) { case 'C': if( objectArray[j] != null) { String str_value = objectArray[j].toString(); dataOutput.write( Utils.textPadding( str_value, characterSetName, this.header.fieldArray[j].getFieldLength())); } else { dataOutput.write( Utils.textPadding( "", this.characterSetName, this.header.fieldArray[j].getFieldLength())); } break; case 'D': if( objectArray[j] != null) { GregorianCalendar calendar = new GregorianCalendar(); calendar.setTime( (Date)objectArray[j]); @SuppressWarnings("unused") StringBuffer t_sb = new StringBuffer(); dataOutput.write( String.valueOf( calendar.get( Calendar.YEAR)).getBytes()); dataOutput.write( Utils.textPadding( String.valueOf( calendar.get( Calendar.MONTH)+1), this.characterSetName, 2, Utils.ALIGN_RIGHT, (byte)'0')); dataOutput.write( Utils.textPadding( String.valueOf( calendar.get( Calendar.DAY_OF_MONTH)), this.characterSetName, 2, Utils.ALIGN_RIGHT, (byte)'0')); } else { dataOutput.write( " ".getBytes()); } break; case 'F': if( objectArray[j] != null) { dataOutput.write( Utils.doubleFormating( (Double)objectArray[j], this.characterSetName, this.header.fieldArray[j].getFieldLength(), this.header.fieldArray[j].getDecimalCount())); } else { dataOutput.write( Utils.textPadding( "?", this.characterSetName, this.header.fieldArray[j].getFieldLength(), Utils.ALIGN_RIGHT)); } break; case 'N': if( objectArray[j] != null) { dataOutput.write( Utils.doubleFormating( (Double)objectArray[j], this.characterSetName, this.header.fieldArray[j].getFieldLength(), this.header.fieldArray[j].getDecimalCount())); } else { dataOutput.write( Utils.textPadding( "?", this.characterSetName, this.header.fieldArray[j].getFieldLength(), Utils.ALIGN_RIGHT)); } break; case 'L': if( objectArray[j] != null) { if( (Boolean)objectArray[j] == Boolean.TRUE) { dataOutput.write( (byte)'T'); } else { dataOutput.write((byte)'F'); } } el