java - 当尝试打开 Excel 工作簿时发生错误时，Try/Catch 不会激活

Question

使用 apache-POI 打开 Excel 工作簿，如果不存在则创建一个。 由于某种原因，正在打开的工作簿已损坏，导致带有错误注释的行发生错误。

不知何故，这部分代码的 try/catch 似乎没有激活。任何想法为什么，以及我如何正确处理这些类型的错误？ 此外，有什么方法可以在我的 if(file.exists() && file.length() != 0) { 条件期间检查文件的完整性？

public XSSFWorkbook OpenWB(String directory, String name) {
      File file = new File(directory + "\\" + name + ".xlsx");
      FileInputStream fIP;

      if(file.exists() && file.length() != 0) {
        try {
            fIP = new FileInputStream(file);
            //Get the workbook instance for XLSX file 
             workbook = new XSSFWorkbook(fIP); //*********error occurs here**********
             fIP.close();
             System.out.println(name + ".xlsx file open successfully.");
             return workbook;
        } catch (IOException e) {
            e.printStackTrace();
             System.out.println("Error to open " + name + ".xlsx file, creating blank");
              //Create Blank workbook
              workbook = new XSSFWorkbook(); 
              Integer i = 0;
              while (file.isFile() && file.exists()) {
                  name = name.concat(i.toString());
                  file = new File(directory + "\\" + name + ".xlsx");
                  i++;
              }
              return workbook;
        }
      } else {
         System.out.println("Error to open " + name + ".xlsx file, creating blank");
          //Create Blank workbook
          workbook = new XSSFWorkbook(); 
          return workbook;
      }
}   

Answer 1

尝试这段代码，它会给你一个错误 “打开 random.xlx 文件时出错，创建空白” 这意味着您的 try catch 正在运行。您似乎忘记初始化变量“工作簿”。

      package stackoverflow;
      import java.io.File;
      import java.io.FileInputStream;
      import java.io.IOException;

      import org.apache.poi.xssf.usermodel.XSSFWorkbook;

      public class Solution {
      public XSSFWorkbook OpenWB(String directory, String name) {
      File file = new File(directory + "\\" + name + ".xlsx");
      FileInputStream fIP;

      XSSFWorkbook workbook;
     if(file.exists() && file.length() != 0) {
        try {
            fIP = new FileInputStream(file);
            //Get the workbook instance for XLSX file 
             workbook = new XSSFWorkbook(fIP); //*********error occurs here**********
             fIP.close();
             System.out.println(name + ".xlsx file open successfully.");
             return workbook;
        } catch (IOException e) {
            e.printStackTrace();
             System.out.println("Error to open " + name + ".xlsx file, creating blank");
              //Create Blank workbook
              workbook = new XSSFWorkbook(); 
              Integer i = 0;
              while (file.isFile() && file.exists()) {
                  name = name.concat(i.toString());
                  file = new File(directory + "\\" + name + ".xlsx");
                  i++;
              }
              return workbook;
        }
      } else {
         System.out.println("Error to open " + name + ".xlsx file, creating blank");
          //Create Blank workbook
          workbook = new XSSFWorkbook(); 
          return workbook;
      }
}  
public static void main(String args[]) {
    Solution s = new Solution();
    s.OpenWB("D://", "random.xlx");
}
 }

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