使用 excel 工作簿时出现异常

Question

当我使用 poi jars 在 excel 工作簿中写入一些数据时，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.access0(Unknown Source)
    at java.net.URLClassLoader.run(Unknown Source)
    at java.net.URLClassLoader.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$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at WorkBookDemo.main(WorkBookDemo.java:27)
Caused by: java.lang.ClassNotFoundException: org.apache.poi.UnsupportedFileFormatException
    at java.net.URLClassLoader.run(Unknown Source)
    at java.net.URLClassLoader.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 13 more

我添加了以下罐子：

xmlbeans-2.4.0
poi-ooxml-schemas-3.11
poi-3.11
commons-logging-1.1
dom4j-1.6.1

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

您缺少 jar 文件。我运行你的代码在我的工作区，我添加了所需的 jars 来构建路径。它相继起作用。

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

您的代码没有错误，它是正确的。将 jars 添加到构建路径。

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。它假定文件 "exps.xlsx" 已经创建。 [Reference.]

以防万一，您只需在 FileOutputStream 构造函数中传递文件名即可。

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

如果尚未创建文件，这将自动创建文件。

此外，我测试了您给定的代码并使用了以下 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>

如果您没有使用 maven 项目，您可以明确添加上述版本的 jars。

Answer 3

你也可以检查重复的 poi jar，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。

Answer 4

下面列出的 apachePOI 库所需的 jar 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 是不同的版本，那么你将得到异常 "java.lang.NoClassDefFoundError: org/apache/poi/UnsupportedFileFormatException"

使用 excel 工作簿时出现异常

exception while using excel workbook

java

apache

excel

apache-poi