dbf.java

geotools的源码

         */
        public StringBuffer GetDbfRec(int row)throws java.io.IOException{
            StringBuffer record;// = new StringBuffer(rec_size);
            if(!isFile){
                return record = new StringBuffer(records[row].toString());
            }
            else{
                record = new StringBuffer(rec_size+numfields);
                
                rFile.seek(data_offset+(rec_size*row));
                //Modifed to use Hisaji ONO's approach for reading multi byte character sets
                byte[] strbuf = new byte[rec_size]; // <---- byte array buffer fo storing string's byte data
                for(int i=0;i<rec_size;i++){
                    strbuf[i] = dFile.readByte(); // <---- read string's byte data
                }
                record.append(new String(strbuf)); // <- append byte array to String Buffer
                return record;
            }
            
        }
	/**
		* fetches the <i>row</i>th row of the file and parses it into an vector
		* of objects.
		* @param row - the row to fetch
		* @exception java.io.IOException on read error.
		*/
   public Vector ParseDbfRecord(int row)throws java.io.IOException{
		return ParseRecord(GetDbfRec(row));
	}
	/**
		* Parses the record stored in the StringBuffer rec into a vector of
		* objects
		* @param StringBuffer rec - the record to be parsed.
		*/

  public Vector ParseRecord(StringBuffer rec){
    Vector record=new Vector(numfields);
    String t;
    Integer I=new Integer(0);
    Float F=new Float(0.0);
    t = rec.toString();
    for(int i=0;i<numfields;i++){
      if(DEBUG)System.out.println(DBC+"type "+fielddef[i].fieldtype);
      if(DEBUG)System.out.println(DBC+"start "+fielddef[i].fieldstart);
      if(DEBUG)System.out.println(DBC+"len "+fielddef[i].fieldlen);
      if(DEBUG)System.out.println(DBC+""+t.substring(fielddef[i].fieldstart,
                  fielddef[i].fieldstart+fielddef[i].fieldlen));
      switch(fielddef[i].fieldtype){
        case 'C':
          record.addElement(t.substring(fielddef[i].fieldstart,
            fielddef[i].fieldstart+fielddef[i].fieldlen));
          break;
        case 'N':
        case 'F':
          if(fielddef[i].fieldnumdec==0)
						try{
							record.addElement(I.decode(t.substring(
								fielddef[i].fieldstart,fielddef[i].fieldstart+fielddef[i].fieldlen)));
						}catch(java.lang.NumberFormatException e){
							record.addElement(new Integer(0));
						}
					else
						try{
							record.addElement(F.valueOf(t.substring(
								fielddef[i].fieldstart,fielddef[i].fieldstart+fielddef[i].fieldlen)));
						}catch(java.lang.NumberFormatException e){
							record.addElement(new Float(0.0));
						}

          break;
        default:
          if(DEBUG)System.out.println(DBC+"Oh - don't know how to parse "
            +fielddef[i].fieldtype);
      }
    }
    return record;
  }

	/**
		* Fetches a column of Integers from the database file.
		* @param int col - the column to fetch
		* @exception java.io.IOException - on read error
		* @exception DbfFileException - column is not an Integer.
		*/
  public Integer[] getIntegerCol(int col )
	throws java.io.IOException,DbfFileException
	{
		return getIntegerCol(col,0,last_rec);
	}
	/**
		* Fetches a part column of Integers from the database file.
		* @param int col - the column to fetch
		* @param int start - the row to start fetching from
		* @param int end - the row to stop fetching at.
		* @exception java.io.IOException - on read error
		* @exception DbfFileException - column is not an Integer.
		*/
  public Integer[] getIntegerCol(int col, int start, int end)
		throws java.io.IOException,DbfFileException {
    Integer column[]=new Integer[end-start];
    String record = new String();
    StringBuffer sb = new StringBuffer(numfields);
    int k=0,i=0;
    if(col>=numfields)
      throw new DbfFileException(DBC+"No Such Column in file: "+col);
    if(fielddef[col].fieldtype!='N')
      throw new DbfFileException(DBC+"Column "+col+" is not Integer "+
				fielddef[col].fieldtype);
		if(start<0)
			throw new DbfFileException(DBC+"Start must be >= 0");
		if(end>last_rec)
			throw new DbfFileException(DBC+"End must be <= "+last_rec);
    // move to start of data
    try{
      for(i=start;i<end;i++){
				sb.setLength(0);
				sb=GetDbfRec(i);
				record=sb.toString();
				if(DEBUG)System.out.println(DBC+record.substring(fielddef[col].fieldstart,
					fielddef[col].fieldstart+fielddef[col].fieldlen).trim()+"*");
				column[i-start]=new Integer(record.substring(fielddef[col].fieldstart,
					fielddef[col].fieldstart+fielddef[col].fieldlen).trim());
      }
    }
    catch(java.lang.NumberFormatException nfe){
        //throw new DbfFileException(DBC+"Column "+col+" contains an non integer id number "+nfe);
			// be nicer
			column[i-start]=new Integer(0);
    }
    catch(java.io.EOFException e){
      System.err.println(e);
      System.err.println("Dbf->record "+i+" byte "+k+" file pos "
      );}
    catch(java.io.IOException e){
      System.err.println(e);
      System.err.println("Dbf->record "+i+" byte "+k+" file pos "
      );}
    return column;
  }
	/**
		* Fetches a column of Floats from the database file.
		* @param int col - the column to fetch
		* @exception java.io.IOException - on read error
		* @exception DbfFileException - column is not an Integer.
		*/
  public Float[] getFloatCol(int col) throws DbfFileException,
  java.io.IOException{
		return getFloatCol(col,0,last_rec);
	}
	/**
		* Fetches a part column of Floats from the database file.
		* @param int col - the column to fetch
		* @param int start - the row to start fetching from
		* @param int end - the row to stop fetching at.
		* @exception java.io.IOException - on read error
		* @exception DbfFileException - column is not an Integer.
		*/
  public Float[] getFloatCol(int col,int start,int end)
		throws DbfFileException, java.io.IOException{
    Float column[]=new Float[end-start];
    String record,st;
    StringBuffer sb = new StringBuffer(rec_size);
    int k=0,i=0;
    if(col>=numfields)
      throw new DbfFileException("Dbf->No Such Column in file: "+col);
    if(fielddef[col].fieldtype!='F'&&fielddef[col].fieldtype!='N')
      throw new DbfFileException("Dbf->Column "+col+" is not Float "
      +fielddef[col].fieldtype);
		if(start<0)
			throw new DbfFileException("Dbf->Start must be >= 0");
		if(end>last_rec)
			throw new DbfFileException("Dbf->End must be <= "+last_rec);
    // move to start of data
    try{
      for(i=start;i<end;i++){
				sb.setLength(0);
				sb=GetDbfRec(i);
        record=sb.toString();
        st=new String(record.substring(fielddef[col].fieldstart,
          fielddef[col].fieldstart+fielddef[col].fieldlen)).trim();
				if(st.indexOf('.')==-1){
					st=st+".0";
				}
				try{
					column[i-start]=new Float(st);
				}catch(java.lang.NumberFormatException e){
					column[i-start]=new Float(0.0);
				}
      }
    }
    catch(java.io.EOFException e){
      System.err.println("Dbf->"+e);
      System.err.println("Dbf->record "+i+" byte "+k+" file pos ");}
    catch(java.io.IOException e){
      System.err.println("Dbf->"+e);
      System.err.println("Dbf->record "+i+" byte "+k+" file pos ");}

    return column;
  }
	/**
		* Fetches a column of Strings from the database file.
		* @param int col - the column to fetch
		* @exception java.io.IOException - on read error
		* @exception DbfFileException - column is not an Integer.
		*/
  public String[] getStringCol(int col) throws DbfFileException,
  java.io.IOException{
		return getStringCol(col,0,last_rec);
	}
	/**
		* Fetches a part column of Strings from the database file.
		* @param int col - the column to fetch
		* @param int start - the row to start fetching from
		* @param int end - the row to stop fetching at.
		* @exception java.io.IOException - on read error
		* @exception DbfFileException - column is not an Integer.
		*/
  public String[] getStringCol(int col,int start,int end)
	throws DbfFileException, java.io.IOException{
    String column[]=new String[end-start];
    String record = new String();
    StringBuffer sb = new StringBuffer(numfields);
    int k=0,i=0;
    if(col>=numfields)
      throw new DbfFileException("Dbf->No Such Column in file: "+col);
    //if(fielddef[col].fieldtype!='C')
      //throw new DbfFileException("Column "+col+" is not a String");
		if(start<0)
			throw new DbfFileException("Dbf->Start must be >= 0");
		if(end>last_rec)
			throw new DbfFileException("Dbf->End must be <= "+last_rec);
    // move to start of data
		try{
			for(i=start;i<end;i++){
				sb.setLength(0);
				sb=GetDbfRec(i);
				record=sb.toString();
				column[i-start]=new String(record.substring(fielddef[col].fieldstart,
					fielddef[col].fieldstart+fielddef[col].fieldlen));
			}
    }
    catch(java.io.EOFException e){
      System.err.println("Dbf->"+e);
      System.err.println("Dbf->record "+i+" byte "+k+" file pos ");}
    catch(java.io.IOException e){
      System.err.println("Dbf->"+e);
      System.err.println("Dbf->record "+i+" byte "+k+" file pos ");}
    return column;
  }
}