The performance optimization technique of Excel Templateer framework in the Java library
Excel Templater is a framework used in the Java library to process Excel files. It provides a simple and flexible way to generate and modify the Excel file.However, when processing a large amount of data and complex formats, Excel Templater may cause performance problems.This article will introduce some performance optimization techniques for the Excel Templateer framework, and provide Java code example for the situation required.
1. Use the appropriate data structure: When using Excel Templateer to generate an excel file, make sure to use the appropriate data structure to store data.If the amount of data is large, you can consider using the XSSF model similar to Apache Poi to process it, which can improve performance and reduce memory consumption.
Example code:
Workbook workbook = new XSSFWorkbook();
Sheet sheet = workbook.createSheet("Sheet1");
// A lot of data processing
for (int row = 0; row < data.size(); row++) {
Row excelRow = sheet.createRow(row);
List<Object> rowData = data.get(row);
for (int col = 0; col < rowData.size(); col++) {
Cell cell = excelRow.createCell(col);
cell.setCellValue(rowData.get(col).toString());
}
}
2. Use template cache: Excel Templateer framework supports the use of templates to generate excel files.If you use the same template when generating the excel file multiple times, you can consider cache the template to avoid repeatedly reading and parsing the template file to improve performance.
Example code:
WorkbookTemplate template = new WorkbookTemplate(new File("template.xlsx"));
// cache template
template.cacheTemplate();
// Multiple generate excel files
for (int i = 0; i < 10; i++) {
Workbook workbook = template.generate();
workbook.write(new FileOutputStream("output_" + i + ".xlsx"));
}
3. Batch operation: If a large number of modification operations are required in the Excel file, you can consider using the batch processing method to avoid the operation of the cell one by one, thereby improving performance.
Example code:
Workbook workbook = new XSSFWorkbook();
Sheet sheet = workbook.createSheet("Sheet1");
// Batch modification unit format
CellStyle cellStyle = workbook.createCellStyle();
cellStyle.setFillForegroundColor(IndexedColors.RED.getIndex());
cellStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
for (int row = 0; row < data.size(); row++) {
Row excelRow = sheet.createRow(row);
List<Object> rowData = data.get(row);
for (int col = 0; col < rowData.size(); col++) {
Cell cell = excelRow.createCell(col);
cell.setCellValue(rowData.get(col).toString());
Cell.SetCellStyle (CellStyle); // Batch setting unit format format
}
}
4. Avoid frequent file reading and writing: When using the Excel Templateer framework, avoid frequent file reading and writing operations, you can consider saving the generated Excel file in memory, and the last one to write files to improve performance.
Example code:
Workbook workbook = new XSSFWorkbook();
Sheet sheet = workbook.createSheet("Sheet1");
// data processing
// Save in memory
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
workbook.write(outputStream);
// Last one -time writing file
FileOutputStream fileOutputStream = new FileOutputStream("output.xlsx");
outputStream.writeTo(fileOutputStream);
fileOutputStream.close();
outputStream.close();
These are some performance optimization techniques for the Excel Templator framework, which can improve the processing speed and performance when processing a large amount of data and complex formats.According to specific needs and scenes, you can choose the appropriate optimization method to improve Excel processing performance.
