org.apache.poi.examples.xssf.streaming.DeferredGeneration Maven / Gradle / Ivy
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package org.apache.poi.examples.xssf.streaming;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.streaming.DeferredSXSSFSheet;
import org.apache.poi.xssf.streaming.DeferredSXSSFWorkbook;
import java.io.FileOutputStream;
import java.io.IOException;
/**
* This sample demonstrates how to use DeferredSXSSFWorkbook to generate workbooks in a streaming way.
* This approach reduces the use of temporary files and can be used to output to streams like
* HTTP response streams.
*/
public class DeferredGeneration {
public static void main(String[] args) throws IOException {
try (DeferredSXSSFWorkbook wb = new DeferredSXSSFWorkbook()) {
DeferredSXSSFSheet sheet1 = wb.createSheet("new sheet");
// cell styles should be created outside the row generator function
CellStyle cellStyle = wb.createCellStyle();
cellStyle.setAlignment(HorizontalAlignment.CENTER);
sheet1.setRowGenerator((ssxSheet) -> {
for (int i = 0; i < 10; i++) {
Row row = ssxSheet.createRow(i);
Cell cell = row.createCell(1);
cell.setCellStyle(cellStyle);
cell.setCellValue("value " + i);
}
});
try (FileOutputStream fileOut = new FileOutputStream("DeferredGeneration.xlsx")) {
wb.write(fileOut);
//writeAvoidingTempFiles was added as an experimental change in POI 5.1.0
//wb.writeAvoidingTempFiles(fileOut);
} finally {
//the dispose call is necessary to ensure temp files are removed
wb.dispose();
}
System.out.println("wrote DeferredGeneration.xlsx");
}
}
}