Quick excel export

Fast excel export
Write a tool class To prevent multithreading poi save threadLocal

/** *  Calling method  */
data = POIUtils4Obj.getSingleSheetData(resultList,Arrays.asList(" user name ", " Age "),Arrays.asList("username", "age");

package xxx;

import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;


public class POIUtils4Obj {
    

	private static ThreadLocal<Workbook> threadLocal = new ThreadLocal<Workbook>();

	/** *  The assembly data is returned to the export stream  * @param contents * @param titles * @param containValuesOrderly * @param sheetName * @return * @throws Exception */
	public static byte[] getSingleSheetData(List<Map<String, Object>> contents,List<String> titles, List<String> containValuesOrderly,String sheetName) throws IOException{
    
		Workbook workBook = createWorkBook();
		threadLocal.set(workBook);
		Sheet sheet = createSheet(workBook, sheetName);
		CellStyle cellStyle = createCellStyle();
		cellStyle.setBorderBottom(BorderStyle.THICK);
		cellStyle.setBottomBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
		cellStyle.setBorderTop(BorderStyle.THICK);
		cellStyle.setTopBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
		cellStyle.setBorderLeft(BorderStyle.THICK);
		cellStyle.setLeftBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
		cellStyle.setBorderRight(BorderStyle.THICK);
		cellStyle.setRightBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
		setTitle(sheet, 0, titles, cellStyle);
		setContent(sheet, 1, contents, containValuesOrderly);
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		workBook.write(out);
		workBook.close();
		return out.toByteArray();
	}

	/** *  Set up title The style of  * @param sheet * @param i * @param titles * @param cellStyle */
	private static void setTitleCustom(Sheet sheet, int i, List<String> titles,CellStyle cellStyle) {
    
		Row titleRow = createRow(sheet, i);
		Cell cell0 = titleRow.createCell(0);
		cell0.setCellStyle(cellStyle);
		cell0.setCellValue(titles.get(0));
		
		Cell cell1 = titleRow.createCell(1);
		cell1.setCellStyle(cellStyle);
		cell1.setCellValue(titles.get(1));

		Cell cell4 = titleRow.createCell(4);
		cell4.setCellStyle(cellStyle);
		cell4.setCellValue(titles.get(2));
	}

	/** *  Create cells and set styles  * @return */
	private static CellStyle createCellStyle() {
    
		CellStyle cellStyle = threadLocal.get().createCellStyle();
// threadLocal.remove();
		cellStyle.setAlignment(HorizontalAlignment.CENTER);
		cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);
		return cellStyle;
	}

	/** *  Set content and style  * @param sheet * @param rowStart * @param contents * @param containValuesOrderly */
	private static void setContent(Sheet sheet,int rowStart,List<Map<String, Object>> contents,List<String> containValuesOrderly) {
    
		int length = contents.size();
		for (int i = 0; i < length; i++) {
    
			Row row = createRow(sheet,rowStart++);
			setRow(row, contents.get(i), containValuesOrderly);
		}
	}

	/** *  Set line content style  * @param row * @param map * @param containValuesOrderly */
	private static void setRow(Row row, Map<String, Object> map, List<String> containValuesOrderly) {
    
		int i = 0;
		CellStyle cellStyle = createCellStyle();
		cellStyle.setBorderBottom(BorderStyle.THIN);
		cellStyle.setBottomBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
		cellStyle.setBorderTop(BorderStyle.THIN);
		cellStyle.setTopBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
		cellStyle.setBorderLeft(BorderStyle.THIN);
		cellStyle.setLeftBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
		cellStyle.setBorderRight(BorderStyle.THIN);
		cellStyle.setRightBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
		for (String key : containValuesOrderly) {
    
			Cell cell = createStringCell(row, i++);
			String value = map.get(key) == null ? "" : String.valueOf(map.get(key));
			cell.setCellStyle(cellStyle);
			cell.setCellValue(value);
		}
	}

	/** *  Determine whether it is a number type , Including decimals , Integers  * */
	private static boolean isNumber(String string){
    
		Pattern pattern = Pattern.compile("^[-+]?(([0-9]+)([.]([0-9]+))?|([.]([0-9]+))?)$");
		Matcher isNum = pattern.matcher(string);
		return isNum.matches();
	}


	/** *  Set up title Content and style  * @param sheet * @param titlenum * @param titles * @param cellStyle */
	private static void setTitle(Sheet sheet,int titlenum,List<String> titles,CellStyle cellStyle) {
    
		int length = titles.size();
		//  Set column width 
		for (int i = 0; i < length; i++) {
    
			sheet.setColumnWidth(i, titles.get(i).getBytes().length*256);
		}
		Row titleRow = createRow(sheet, titlenum);
		for (int i = 0; i < length; i++) {
    
			Cell title = createStringCell(titleRow, i);
			title.setCellStyle(cellStyle);
			title.setCellValue(titles.get(i));
		}
	}

	/** *  establish  String  Format  cell * @param row * @param column * @return */
	private static Cell createStringCell(Row row,int column) {
    
		return row.createCell(column, CellType.STRING);
	}

	/** *  establish  Row * @param sheet * @param rownum * @return */
	private static Row createRow(Sheet sheet, int rownum) {
    
		return sheet.createRow(rownum);
	}

	/** *  establish  workBook * @return * @throws IOException */
	private static Workbook createWorkBook() throws IOException {
    
		Workbook workBook = new XSSFWorkbook();
		return workBook;
	}

	/** *  establish  sheet  page  * @param workbook * @param sheetName * @return */

	private static Sheet createSheet(Workbook workbook,String sheetName) {
    
		return workbook.createSheet(sheetName);
	}


}