Reading a string in java

Question

I am working on this code for a school to create a course, users, students, and teachers, but I encountered a problem while creating the course.

What I want to do (in the terminal) is to read an input stream such as "CSC 110 Into to java" and enter all of it into a string. I use Scanner for input. and tried hasNext () and nextLine () besides next (). I was thinking of writing a function to use a char array to get the whole string, and then convert the char array to a string.

At first I wanted to know if there was a simpler solution?

Edit: Sorry, I was not clean. Without going into all my code.

Current Code:

System.out.print("Enter the Course Title: "); title = keyboard.nextLine(); System.out.print("Enter a Brief Course Description: "); desc = keyboard.nextLine(); if (t != null) { do { System.out.println("\nPick a teacher\n"); for (int j = 0; j < t.size(); j++) { nTeacher = t.get(j); s += "\t(" + (j+1) + ") " + nTeacher + "\n"; } System.out.print(s + "\nEnter the Teacher ID: "); int tId = keyboard.nextInt(); // My error 

Current error:

 Enter the Course Title: CSC 110 Into to java Enter a Breif Course Description: Pick a teacher Enter the Teacher ID: Exception in thread "main" java.util.InputMismatchException at java.util.Scanner.throwFor(Scanner.java:857) at java.util.Scanner.next(Scanner.java:1478) at java.util.Scanner.nextInt(Scanner.java:2108) at java.util.Scanner.nextInt(Scanner.java:2067) at Prototype.classCreator(Prototype.java:530) at Prototype.mainMenu(Prototype.java:181) at Prototype.login(Prototype.java:121) at Prototype.main(Prototype.java:48) 

When I use nextLine ()

 Create Class Enter the courseID: 27222 Enter the Course Title: Enter a Brief Course Description: 

Expected Result:

 Create Class Enter the courseID: 27299 Enter the Course Title: CSC 110 Into to Java Enter a Brief Course Description: Introduction to programming Pick a teacher (1) ID: 1111 Name: Bob Enter the Teacher ID: 1 Class Created 

I understand that when I have three lines of "CSC 110 Intro", it gets input for nextInt (), but I don’t understand why nextLine () writes my println as follows.

Answer 1

Well, you didn’t tell us exactly what the error is, so I’ll just give an example Scanner code and let you work with this:

 //create the Scanner Scanner terminalInput = new Scanner(System.in); //read input String s = terminalInput.nextLine(); 

This should work; The scanner is one of the simplest classes. You may have accidentally used

 new Scanner(); //no input source! 

but not

 new Scanner(System.in); //links to terminal 

EDIT:

I suggested that you call

 keyboard.nextInt(); 

and later

 keyboard.nextLine(); 

This is what messed up your program. The nextInt () method leaves the character "\ n" endline and immediately sticks to nextLine (), skipping the next input. What you want to do is use nextLine for everything and analyze it later:

 String nextIntString = keyboard.nextLine(); //get the number as a single line int nextInt = Integer.parseInt(nextIntString); //convert the string to an int 

This is by far the easiest way to avoid problems - do not mix your “next” methods. Use only nextLine () and then parse the ints / single words.

Answer 2

 Scanner scan = new Scanner(System.in); String str_input = scan.nextLine(); 

Will this work for you?

Answer 3

You can use new Scanner(System.in) as mentioned by several people, or you can also try the following:

 BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); String s = br.readLine(); 

Answer 4

 BufferedReader bufferedReader = new BufferedReader(new FileReader(fileName)); 

That would be the way you would read it from the btw file.

I think BufferedReader is better than a scanner, simply because it does what it says, it's buffers.

But the scanner works too.

Try to make a configuration file, and not read it from the command line.

 Properties configFile = new Properties(); configFile.load(new FileInputStream("conf.properties")); myString = configFile.getProperty("MY_STRING"); 

The configuration file will be called conf.properties, and then it will have in it:

 MY_STRING = blahblahbah