package exception; import org.apache.poi.ss.formula.functions.IfFunc; public class CustomException extends RuntimeException{ static final long serialVersionUID = -9876543211111L;//异常的版本号：用来标识独一无二的异常 public CustomException(String message) { super(message); } public CustomException() { } public CustomException(String message, Throwable cause) { super(message, cause); } @Override public String toString() { return "发生了CustomException，请再次检查操作是否符合规范"; }//用来描述发生的异常和原因 }