问在HSSFWorkbook中设置活动单元

EN

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Field;

import org.apache.poi.hssf.model.InternalSheet;
import org.apache.poi.hssf.record.SelectionRecord;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.hssf.util.CellRangeAddress8Bit;
import org.apache.poi.ss.util.CellAddress;

public class ExcelGeneratorDemo {

    public static void main(String[] args) throws IOException {
        writeExcelFile("D21");
    }

    private static void writeExcelFile(String activeCell) throws IOException {
        HSSFWorkbook wb = new HSSFWorkbook();
        HSSFSheet sheet = wb.createSheet();
        CellAddress address = new CellAddress(activeCell);
        setActiveCell(sheet, address);
        wb.write(new File(activeCell + ".xls"));
    }

    /**
     * Calling just {@code sheet.setActiveCell} has no effect when opening
     * the file with Microsoft Excel 2016.
     */
    private static void setActiveCell(HSSFSheet sheet, CellAddress address) {
        sheet.setActiveCell(address);

        // Following three private fields in a row cannot be the correct path.
        InternalSheet internalSheet = getField(sheet, "_sheet");
        SelectionRecord selection = getField(internalSheet, "_selection");
        CellRangeAddress8Bit[] ranges = getField(selection, "field_6_refs");

        ranges[0].setFirstColumn(address.getColumn());
        ranges[0].setLastColumn(address.getColumn());
        ranges[0].setFirstRow(address.getRow());
        ranges[0].setLastRow(address.getRow());
    }

    private static <T> T getField(Object obj, String fieldName) {
        try {
            Field field = obj.getClass().getDeclaredField(fieldName);
            field.setAccessible(true);
            return (T) field.get(obj);
        } catch (ReflectiveOperationException e) {
            throw new IllegalStateException(e);
        }
    }
}