Question

我在使用poi jar在excel工作簿中编写一些数据时，我的代码中出现了这些异常：

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

我添加了以下罐子：

的xmlbeans-2.4.0
POI-OOXML-架构 - 3.11
POI-3.11
共享记录-1.1
DOM4J-1.6.1

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

你丢失了jar文件。我在我的工作区中运行了代码，并添加了必需的jar来构建路径。它先后工作。

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

代码中没有错误是正确的。添加jar来构建路径。

Answer 2

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.

因为您显式创建了一个File对象，并将其传递给FileOutputStream构造函数。它假定已创建文件"exps.xlsx"。 [Reference.]

Incase，它不是，你只需在FileOutputStream构造函数中传递文件的名称。

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

这将自动创建文件，因为它尚未创建。

此外，我测试了您的给定代码并使用了以下Maven依赖项并且它有效。

<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>

如果你没有使用maven项目，你可以明确地添加前面提到的jars版本。

Answer 3

apachePOI库所需的以下jar列表应该都是相同的版本，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jar有不同的版本，那么你将获得异常＆＃34; java.lang.NoClassDefFoundError：org / apache / poi / UnsupportedFileFormatException＆＃34;

Answer 4

你也可以检查重复的poi罐子，假设你需要poi-ooxml-3.9。罐。但是在你的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，它应该可以工作。

使用excel工作簿时出现异常

4 个答案: