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【poi导出excel文件】Java：实现文件批量导入导出实践（兼容xls,xlsx）

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作者：小卖铺的老爷爷 cnblogs.com/laoyeye/p/6938889.html 1、介绍 java实现文件的导入导出数据库，目前在大部分系统中是比较常见的功能了，今天写个小demo来理解其原理，没接触过的同学也可以看看参考下。目前我所接触过的导入导出技术主要有POI和iReport，poi主要作为一些数据批量导入数据库，iReport做报表导出。另外还有jxl类似poi的方式，不过貌似很久没跟新了，2007之后的office好像也不支持，这里就不说了。 2、POI使用详解 2.1 什么是Apache POI？ Apache POI是Apache软件基金会的开放源码函式库，POI提供API给Java程序对Microsoft Office格式档案读和写的功能。 2.2 POI的jar包导入本次讲解使用maven工程，jar包版本使用poi-3.14和poi-ooxml-3.14。目前最新的版本是3.16。因为3.15以后相关api有更新，部分操作可能不一样，大家注意下。  <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi</artifactId> <version>3.14</version> </dependency>

解决Java POI导出海量Excel数据内存溢出

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使用POI导出Excel数据的时候有两个方法可以创建WorkBook： HSSFWorkbook:是操作Excel2003以前（包括2003）的版本，扩展名是.xls XSSFWorkbook:是操作Excel2007的版本，扩展名是.xlsx 当数据量超出65536条后，在使用HSSFWorkbook或XSSFWorkbook，程序会报 OutOfMemoryError：Javaheap space 内存溢出错误。从POI 3.8版本开始，提供了一种基于XSSF的低内存占用的API，也就是SXSSFWorkbook。 SXSSFWorkbook-来至官方的解释：实现“BigGridDemo”策略的流式XSSFWorkbook版本。这允许写入非常大的文件而不会耗尽内存，因为任何时候只有可配置的行部分被保存在内存中。您可以提供用作书面数据基础的模板工作簿。有关详细信息，请参见https://poi.apache.org/spreadsheet/how-to.html#sxssf 请注意，仍然可能会消耗大量内存，这些内存基于您正在使用的功能，例如合并区域，注释......仍然只存储在内存中，因此如果广泛使用，可能需要大量内存。SXSSFWorkbook默认使用内联字符串而不是共享字符串表。这非常有效，因为没有文档内容需要保存在内存中，但也被称为制作与某些客户不兼容的文档

Creating a checkbox in XLSX using Apache POI (Java)

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问题 I need to create an Excel checkbox in an XSSFSheet, but I have found no obvious classes/methods for doing so in the Java Apache POI library (4.0.1), nor any examples. Any suggestions? 回答1: There are two types of controls possible in Microsoft Excel . There are the legacy form controls and ActiveX controls. Creating legacy form controls would be possible. ActiveX controls wold be much more complex. The legacy form controls are stored in VML drawings per sheet. Apache poi has a XSSFVMLDrawing

Creating a checkbox in XLSX using Apache POI (Java)

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Copy a XSSF/HSSF-Cells into a new XSSFWorkbook

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问题 My problem I need to exactly copy cells from XSSFWorkbook s and HSSFWorkbook s to a new XSSFWorkbook . So my cells can be of both types: XSSFCell and HSSFCell . By exactly , I mean that I also need to copy the CellStyle including the CellBorder and CellFill properties as well as the DefaultRowHeight and DefaultColumnWidth of the workbook itself. Also the height and width for each row and column should be copied. (Copying CellStyle sometimes results in strange behaviour like I already asked

java.lang.ClassNotFoundException: org.apache.poi.xssf.usermodel.XSSFWorkbook

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问题 when i tried to create a workbook in normal java class it is creating but when i tried to run the same on servlet it is throwing exceptions Normal java class import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import org.apache.poi.ss.usermodel.Workbook; import org.apache.poi.xssf.usermodel.XSSFWorkbook; public class Sampleclass { public static void main(String[] args) { FileInputStream file; try { file = new FileInputStream

Auto wrap in apache POI (Excel)

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问题 I have a java program which takes header and data as the input and produces an excel file. However, sometimes when the header values are long and the number of columns are more, my excel sheet tends to be unnecessarily wide. Because of the headers, I will have to scroll down to right to see the content of the tail end columns. Is there a way I can resolve this such that if the content in the cell is bigger then say value x, then auto wrap occurrs and automatically the row height gets adjusted

Apache POI : Excel Pivot Table - Row Label

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问题 I have a requirement to create a excel sheet in JAVA as below : I am not able to create a row label with multiple columns side by side ( menus and submenus filter ). Instead of displaying the submenu in different column, its coming under the menu column. Below is the piece of code which i have written : XSSFSheet sheet = my_xlsx_workbook.getSheetAt(0); AreaReference a=new AreaReference("A1:G7"); CellReference b=new CellReference("I5"); XSSFPivotTable pivotTable = sheet.createPivotTable(a,b);

Apache poi XSSF Creating Excel Files - Create returns empty file with format or file extension not valid?

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问题 The relevant part of the Controller class: @RequestMapping(value = "/DBCompare/download", method = RequestMethod.GET) public void handleDownloadDBCompareReportGet(HttpServletResponse response, Model model){ try{ reportService.downloadResultsDto(reportDto); } finally{ } } The ReportService in this case only fetches some information from the database, and calls newTableCompare() from the CreateTable class. The following class should create a new Excel table, workbook, ect. import java.io

Java Memory issue using Apache.POI to read write Excel

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问题 I am trying to read excel file...make some changes...save to new file. I have created small form with button...On pressing button.. It will load Excel file and load all data to Array list of class I have created. It will loop through Array list and change few properties in objects. It will save data to new Excel file. Finally, it will clear Array list and show message box of completion. Now the problem is memory issue. When form is loaded, I can see in windows task manager...javaw is using