Apache POI – 读取修改excel文件

每当我使用Apatche POI打开excel文件时，文件都会被修改，即使我只是在阅读文件而没有进行任何修改。

以此类测试代码为例。

public class ApachePoiTest { @Test public void readingShouldNotModifyFile() throws Exception { final File testFile = new File("C:/work/src/test/resources/Book2.xlsx"); final byte[] originalChecksum = calculateChecksum(testFile); Assert.assertTrue("Calculating checksum modified file", MessageDigest.isEqual(originalChecksum, calculateChecksum(testFile))); try (Workbook wb = WorkbookFactory.create(testFile)) { Assert.assertNotNull("Reading file with Apache POI", wb); } Assert.assertTrue("Reading file with Apache POI modified file", MessageDigest.isEqual(originalChecksum, calculateChecksum(testFile))); } @Test public void readingInputStreamShouldNotModifyFile() throws Exception { final File testFile = new File("C:/work/src/test/resources/Book2.xlsx"); final byte[] originalChecksum = calculateChecksum(testFile); Assert.assertTrue("Calculating checksum modified file", MessageDigest.isEqual(originalChecksum, calculateChecksum(testFile))); try (InputStream is = new FileInputStream(testFile); Workbook wb = WorkbookFactory.create(is)) { Assert.assertNotNull("Reading file with Apache POI", wb); } Assert.assertTrue("Reading file with Apache POI modified file", MessageDigest.isEqual(originalChecksum, calculateChecksum(testFile))); } private byte[] calculateChecksum(final File file) throws Exception { final MessageDigest md = MessageDigest.getInstance("MD5"); md.reset(); try (InputStream is = new FileInputStream(file)) { final byte[] bytes = new byte[2048]; int numBytes; while ((numBytes = is.read(bytes)) != -1) { md.update(bytes, 0, numBytes); } return md.digest(); } } } 

测试readingShouldNotModifyFile总是失败，因为该文件总是被Apache POI修改。 在使用MS Office新创建的空白excel文件上进行测试时，Apache POI会将文件从8.1 kb切换到6.2 kb并破坏文件。

经测试：

  org.apache.poi poi-ooxml 3.15  

以及版本3.12

我可以通过其他方式阻止Apache POI修改我的文件，然后传递InputStream而不是File 。 我不想传递InputStream因为我担心Apache会警告它需要更多内存并且对InputStream有一些特定要求。

Answer 1

您的问题是您没有传入readonly标志，因此Apache POI默认为打开文件读/写。

您需要使用重载的WorkbookFactory.create方法，该方法将readonly标志 + set设置为readonly标志为true

改变线

 try (InputStream is = new FileInputStream(testFile); Workbook wb = WorkbookFactory.create(is)) { 

至

 try (IWorkbook wb = WorkbookFactory.create(testFile,null,true)) { 

并且您的文件将以只读方式打开而不进行任何更改