Trying to get data from excel then store it inside array and later print it

Question

I am trying to read data from an excel file. When i run the below code it runs without any error but won't give any data. When i checked the code i found that the global variable rownum is not initializing and giving the default value which is 0. But inside the getData(int i) method the rownum is giving a value of 14. I am trying to get all string data available in excel file by using getData(int i) method and later trying to store them inside data[] array. Again inside the setData method i am trying to copy all item stored inside the data[] array to a string value. Can anyone please help. I am new to java. package com.selenium;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.usermodel.WorkbookFactory;


@SuppressWarnings("unused")
public class DataFromExcel {
  String[] data = new String[15];
  static int rownum;

 public String[] getData(int i) throws InvalidFormatException, IOException{
   File file = new File("C:\\Users\\Admin\\Desktop\\ScreenShot\\Excel.xls");
   FileInputStream input = new FileInputStream(file);
   Workbook excel = WorkbookFactory.create(input);
   Sheet sheet = excel.getSheet("Data");
   rownum = sheet.getLastRowNum();
   System.out.println(rownum);


     for(int j=1;j<=rownum;j++){
         Row row = sheet.getRow(rownum);
         while(row != null){
         if(row.getCell(j) != null){
         String cell = row.getCell(j).getStringCellValue();
         while(cell != null){
             data[j]=cell;
             System.out.println(data[1]);
         }//while cell
        }//if row 
      }//for  
     }//row while
    return data;
   }//getData 
  public String setData(int i){
      String value = null;
      for(i=1; i<=data.length;i++){
          value =data[i];
      }//for setData
    return value;
  }//setData

 public static void main(String[] args) throws InvalidFormatException, IOException{
    DataFromExcel get = new DataFromExcel();
    System.out.println(rownum);
    get.getData(1);
    if(get.data != null){
    System.out.println(get.setData(1));}
 }//main
}// DataFromExcel

Answer 1

您已经知道（我期望如此） ，该程序的执行是从main()方法开始的。现在，当您调用getData(int i)方法时，此时rownum为零（显然没有代码在修改。它），但随后您调用了带有参数的getData(int i) ，该参数随后根据其中的指令更改了rownum的值，请尝试添加另一个System.out.prinltn()作为main()方法的结束行并打印rownum.的值rownum.