java - 读取 xlsx 文件行时 Apache POI ClassCastException

Question

我正在编写一个类，它使用 apache-poi 库来迭代 xlsx 工作表并获取一些 UPC 编号。应用程序本身在 TOMCAT 服务器上运行 - 代码编译时没有任何错误，但我收到一个奇怪的运行时错误有人知道为什么会发生这种情况吗？我使用 maven 来获取 poi 依赖项，所以这有点意外:

type Exception report

message org.apache.poi.xssf.usermodel.XSSFRow cannot be cast 
to org.apache.poi.ss.usermodel.Row

description The server encountered an internal error that prevented it 
from fulfilling this request.

异常

java.lang.ClassCastException: org.apache.poi.xssf.usermodel.XSSFRow cannot be cast to org.apache.poi.ss.usermodel.Row
    com.riverboat.util.RiverBoatExcelParser.parseXLSManifest(RiverBoatExcelParser.java:51)
    com.riverboat.servlets.FileManagerServlet.doPost(FileManagerServlet.java:113)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

注意 Apache Tomcat (TomEE)/7.0.53 (1.6.0.2) 日志中提供了根本原因的完整堆栈跟踪。

编辑:这是 Pom 文件

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-     instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<dependencies>
  <dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.3.6</version>
  </dependency>
  <dependency>
    <groupId>net.minidev</groupId>
    <artifactId>json-smart</artifactId>
    <version>1.3</version>
  </dependency>
  <dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.10.1</version>
  </dependency>
</dependencies>
<modelVersion>4.0.0</modelVersion>
<groupId>RiverBoat</groupId>
<artifactId>RiverBoat</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<build>
    <sourceDirectory>src</sourceDirectory>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.1</version>
        <configuration>
          <source>1.7</source>
          <target>1.7</target>
        </configuration>
      </plugin>
      <plugin>
        <artifactId>maven-war-plugin</artifactId>
        <version>2.3</version>
        <configuration>
          <warSourceDirectory>WebContent</warSourceDirectory>
          <failOnMissingWebXml>false</failOnMissingWebXml>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

这是java代码:

package com.riverboat.util;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

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 RiverBoatExcelParser {

FileInputStream spreadsheet;

public RiverBoatExcelParser(InputStream file)
{
    spreadsheet = (FileInputStream)file;
}

/*
 * Parse an XLS spread sheet
 */
public void parseXLSManifest(int book, String UPCColumnHeader)
{
    String currText;
    boolean foundUPC = false;
    List<ExcelManifestRecord> result = new ArrayList<>();
    int current_row = 0;
    int current_col = 0;
    int upc_row;
    int upc_col=0;

    try {
        //Create workbook instance to hold file reference to .xlsxfile
        XSSFWorkbook workbook = new XSSFWorkbook(spreadsheet);

        //Get first/desire sheed from the workbook
        XSSFSheet sheet = workbook.getSheetAt(book);

        //Iterate through each row one by one
        Iterator<Row> rowIterator = sheet.iterator();

        while(rowIterator.hasNext())
        {
            Row row = rowIterator.next();

            //For each row,  iterate through all the colums
            Iterator<Cell> cellIterator = row.cellIterator();
            ExcelManifestRecord rec = new ExcelManifestRecord();

            while(cellIterator.hasNext())
            {
                Cell cell = cellIterator.next();
                current_col++;

                switch(cell.getCellType())
                {
                    case Cell.CELL_TYPE_STRING:
                        currText = cell.getStringCellValue();

                        //check for the upc column header
                        if(currText.equalsIgnoreCase(UPCColumnHeader))
                        {
                            upc_col = current_col;
                            foundUPC = !foundUPC;       
                        }
                        //TODO: init row/column 
                        break;
                    case Cell.CELL_TYPE_NUMERIC:
                        if(current_col == upc_col && foundUPC)
                        {
                            rec.UPC = (int)cell.getNumericCellValue();
                            System.out.println("Found UPC "+rec.UPC);
                        }
                        break;
                }
            }
            current_col = 0;
        }           
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

Answer 1

您还需要 xssf 的此依赖项:

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.10.1</version>
</dependency>

如果您现在没有收到编译错误，则意味着您有来自其他地方的依赖项，可能您的 RiverBoat 项目公开了旧的/不兼容的版本。因此，您要么需要此 pom 中的两个 poi 依赖项，要么不需要(因为两者都可能由 RiverBoat 公开)。