How to fix error in substring due to spaces

Question

I am trying to take specific values from a file to write to the database through Java. I have used the substring() function to store values. In one column, I have some empty fields and some with data. When it encounters an empty field, it gives me an error. How to fix this?

String st = strline.substring(453,457);

I am getting this error in output due to the above code:

Error: begin 453, end 457, length 452

Answer 1

像厄立特里亚一样，你应该在调用substring方法之前检查字符串的长度。

String st = strline.length() > 452 ? strline.substring(453,457) : "";