我得到空指针异常 [英] I'm getting null pointer exception

问题描述

import java.sql.*;
 public class GetText{
 public static void getTextFromDb(String FilePath)
      {
      Connect conn=new Connect();
      Connection con2=null;
      
      
      try {
         ResultSet rs =null;
         CallableStatement cstmt = con2.prepareCall("{call FileExtract(?)}");
         cstmt.setString("FilePath",FilePath);
         cstmt.registerOutParameter(1, Types.VARCHAR);
         cstmt.registerOutParameter(2, Types.VARCHAR);
         rs=cstmt.executeQuery();
         while(rs.next())
         {
         String FP=rs.getString(1);
         String data=rs.getString(2);
         System.out.println("FilePath:"+FP);
         //System.out.println(+FP);
         System.out.println("FileData:"+data);
         //System.out.println(+data);
         } 
         cstmt.close();
    }
    catch (Exception e) 
    {
        e.printStackTrace();
    }
      
      
      }
      public static void main(String[] args)
      {
       String P=args[0];
       GetText g=new GetText();
       g.getTextFromDb(P);
       
      }
      }

推荐答案

我的猜测，OutParams应为0& 1基于而不是1& 2：

My guess, OutParams should be 0 & 1 based instead of 1 & 2:

cstmt.registerOutParameter(0, Types.VARCHAR);
      cstmt.registerOutParameter(1, Types.VARCHAR);

试试！

Try!

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