例外，而使用Excel工作簿

Question

我在我的代码让这些异常而即时通讯使用的POI罐子在Excel工作簿写一些数据：

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/poi/UnsupportedFileFormatException 
    at java.lang.ClassLoader.defineClass1(Native Method) 
    at java.lang.ClassLoader.defineClass(Unknown Source) 
    at java.security.SecureClassLoader.defineClass(Unknown Source) 
    at java.net.URLClassLoader.defineClass(Unknown Source) 
    at java.net.URLClassLoader.access$100(Unknown Source) 
    at java.net.URLClassLoader$1.run(Unknown Source) 
    at java.net.URLClassLoader$1.run(Unknown Source) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at java.net.URLClassLoader.findClass(Unknown Source) 
    at java.lang.ClassLoader.loadClass(Unknown Source) 
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) 
    at java.lang.ClassLoader.loadClass(Unknown Source) 
    at WorkBookDemo.main(WorkBookDemo.java:27) 
Caused by: java.lang.ClassNotFoundException: org.apache.poi.UnsupportedFileFormatException 
    at java.net.URLClassLoader$1.run(Unknown Source) 
    at java.net.URLClassLoader$1.run(Unknown Source) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at java.net.URLClassLoader.findClass(Unknown Source) 
    at java.lang.ClassLoader.loadClass(Unknown Source) 
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) 
    at java.lang.ClassLoader.loadClass(Unknown Source) 
    ... 13 more 

我添加下列jar：

1. 的xmlbeans-2.4。 0
2. POI-OOXML-架构 - 3.11
3. POI-3.11
4. 共享记录-1.1
5. dom4j的-1.6.1

6. 的log4j-1.2.17

   import java.io.File; 
   import java.io.FileOutputStream; 
   
   import java.util.Map; 
   import java.util.Set; 
   import java.util.TreeMap; 
   
   import org.apache.poi.ss.usermodel.Cell; 
   import org.apache.poi.ss.usermodel.Row; 
   import org.apache.poi.xssf.usermodel.XSSFSheet; 
   import org.apache.poi.xssf.usermodel.XSSFWorkbook; 
   
   public class WorkBookDemo { 
   
       public static void main(String[] args) 
       { 
        //Blank workbook 
        XSSFWorkbook workbook = new XSSFWorkbook(); 
   
        //Create a blank sheet 
        XSSFSheet sheet = workbook.createSheet("Employee Data"); 
   
        //This data needs to be written (Object[]) 
        Map<String, Object[]> data = new TreeMap<String, Object[]>(); 
        data.put("1", new Object[] {"ID", "NAME", "LASTNAME"}); 
        data.put("2", new Object[] {1, "Amit", "Shukla"}); 
        data.put("3", new Object[] {2, "Lokesh", "Gupta"}); 
        data.put("4", new Object[] {3, "John", "Adwards"}); 
        data.put("5", new Object[] {4, "Brian", "Schultz"}); 
   
        //Iterate over data and write to sheet 
        Set<String> keyset = data.keySet(); 
        int rownum = 0; 
        for (String key : keyset) 
        { 
         Row row = sheet.createRow(rownum++); 
         Object [] objArr = data.get(key); 
         int cellnum = 0; 
         for (Object obj : objArr) 
         { 
          Cell cell = row.createCell(cellnum++); 
          if(obj instanceof String) 
           cell.setCellValue((String)obj); 
          else if(obj instanceof Integer) 
           cell.setCellValue((Integer)obj); 
         } 
        } 
        try 
        { 
        //Write the workbook in file system 
         FileOutputStream out = new FileOutputStream(new File("exps.xlsx")); 
         workbook.write(out); 
         out.close(); 
         System.out.println("exps.xlsx written successfully on disk."); 
        } 
        catch (Exception e) 
        { 
         e.printStackTrace(); 
        } 
       } 
   
   } 
   

Answer 1

FileOutputStream out = new FileOutputStream(new File("exps.xlsx")); 

A file output stream is an output stream for writing data to a File or to a FileDescriptor. Whether or not a file is available or may be created depends upon the underlying platform. Some platforms, in particular, allow a file to be opened for writing by only one FileOutputStream (or other file-writing object) at a time. In such situations the constructors in this class will fail if the file involved is already open.

既然你明确地创建一个File对象，并通过同向FileOutputStream构造。它假定文件"exps.xlsx"已经创建。 [Reference.]

因此，不是，您只需在FileOutputStream构造函数中传递文件的名称即可。

FileOutputStream out = new FileOutputStream("exps.xlsx"); 

这会自动创建文件，因为它已经没有被创建。

此外，我测试了您的给定代码，并使用以下Maven依赖项，它的工作。

<dependency> 
    <groupId>org.apache.poi</groupId> 
    <artifactId>poi</artifactId> 
    <version>3.10-FINAL</version> 
</dependency> 
<dependency> 
    <groupId>org.apache.poi</groupId> 
    <artifactId>poi-ooxml</artifactId> 
    <version>3.10</version> 
</dependency> 

柜面你不使用maven项目，你可以明确地添加上述版本的上述jars。

Answer 2

你丢失了一些JAR-文件。我在工作区中运行了代码，并添加了所需的jar来构建路径。它连续工作。

org/apache/poi/UnsupportedFileFormatException is under poi-x.xx-xxx-xx.jar 

代码中没有错误，它是正确的。添加罐子来建立路径。

Answer 3

你可以检查重复的poi罐子，假设你需要poi-ooxml-3.9。罐。但在你的lib文件夹中有poi-ooxml-3.11.jar，poi-ooxml-3.9.jar然后删除poi-ooxml-3.11.jar，它应该工作。

Answer 4

应该都是同一个版本需要apachePOI库罐的下面列表如下所示：

org.apache.poi.3.11 
org.apache.poi-ooxml.3.11 
org.apache.poi-ooxml-schemas.3.11 

如果同一个库的上述罐子是不同的版本，那么你也会得到异常的“java.lang.NoClassDefFoundError：org/apache/poi/UnsupportedFileFormatException”