生成Excel报表

package top.zzzwww.utils;
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import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFDataFormat;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
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import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
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public class ApachePoiUtil2 {
    public static void main(String[] args) throws Exception {
        OutputStream os = new FileOutputStream("F:\\test.xls");
        Workbook wb = new HSSFWorkbook();
        ApachePoiUtil2 test = new ApachePoiUtil2();
        test.createFile(os, wb);
    }
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    private void createFile(OutputStream os,Workbook wb) throws IOException{
        int i = 0;
        int j = 0;
        double
        = 0.00;
        double ref_amt = 0.00;
        String[] refundLogs = new String[2];
        String str1 = "20110812|34234234242432|345.00|323   .00";
        String str2 = "20110504|45656464535345|231.34|231.34";
        refundLogs[0] = str1;
        refundLogs[1] = str2;
        // 创建工作表指定工作表名称
        Sheet sheet = wb.createSheet("T建行退款文件");
        // 创建行，0表示第一行
        Row row = sheet.createRow(0);
        for(i=1;i<=3;i++){
            sheet.createRow(i);
        }
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        for(i=0;i<4;i++)
            row.createCell(i);
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        // 合并单元格
        sheet.addMergedRegion(new CellRangeAddress(0, 3, 0, 3));
        //CellRangeAddress（int firstRow, int lastRow, int firstCol, int lastCol）
        //参数：起始行号，终止行号， 起始列号，终止列号
        // 设置字体
        Font font = wb.createFont();
        // 设置字体名称
        font.