java编程实现根据EXCEL列名求其索引的方法

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import java.util.HashMap; 
import java.util.Map; 
/** 
 * 
 * @author jdkleo 
 */ 
public class ExcelUtil { 
  public static int getCellNum(String cellStr) { 
    char[] cellStrArray = cellStr.toUpperCase().toCharArray(); 
    int len = cellStrArray.length; 
    int n = 0; 
    for(int i=0;i<len;i++){ 
      n += (((int)cellStrArray[i])-65+1)*Math.pow(26, len-i-1); 
    } 
    return n-1; 
  } 
  public static void main(String[] args) { 
    System.out.print(getCellNum("aaa")); 
  } 
}