How do you determine if a string contains another operator?

public static void main(String[] args) {
		
		try {
		
		Scanner scanner = new Scanner(System.in);
		
		System.out.println("Enter your calculation");
		
		String text = scanner.nextLine();
		
		for(int i = 0; i < text.length();i++) {
			
			if(text.substring(i,i+1).equals("+")) {
				
				String behind = text.substring(i-i,i);
				String ahead = text.substring(i+1,text.length());
				
				System.out.println(behind);
				System.out.println(ahead);
			}
			
			if(text.substring(i,i+1).equals("-")) {
				
				String behind = text.substring(i-i,i);
				String ahead = text.substring(i+1,text.length());
			    
				
			}
			
	      }
		
		} catch(Exception e) {
			System.out.println(e.getMessage());
			main(args);
		}
		
	  }

if(text.substring(i,i+1).equals("+")) {
				
				String behind = text.substring(i-i,i);
				String ahead = text.substring(i+1,text.indexOf("+"));
				
				System.out.println(behind);
				System.out.println(ahead);
			}
			
			if(text.substring(i,i+1).equals("-")) {
				
				String behind = text.substring(i-i,i);
				String ahead = text.substring(i+1,text.indexOf("-"));
			    
				
			}