We use hasNext() method in a while loop so that it prints every word until it reaches the last word. This method by default uses space as a delimiter. To read individual words, we use the next() method. In the below example, we use String as the input source. Java Scanner next() example using String input Hence we pass System.in to the scanner object. Here, we use the nextInt() to read the integer value input from the user through keyboard input. Java Scanner nextInt() example using System.in nextLine() method reads a single input line until it encounters “\n” (end of line). In the below example, we are creating a scanner object to read the Java user input using System.in which is nothing but the keyboard input. InputMismatchException – when the input does not match with the expected type Scanner nextLine() example using System.in.NoSuchElementException – when there is no token found.IllelgalStateException – when we attempt to perform search operation on closed scanner object.Java Scanner class throws the below exceptions while trying to read input: Returns a word boolean hasNext(Pattern pattern) Returns true if the next token matches the pattern specified boolean hasNextBigDecimal() Returns true if the next token has a BigDecimal boolean HasNextBigInteger() Returns true if the next token has BigInteger boolean hasNextBigInt() Returns true if the next token is BigInt boolean HasNextBoolean() Returns true if the next token is boolean boolean hasNextFloat() Returns true if the next token is Floatīoolean hasNextDouble() Returns true if the next token is Double boolean hasNextLine() Returns true if the scanner has another input line String next() Finds and returns the next complete token in the input BigDecimal nextBigDecimal() Returns the BigDecimal value from the input BigInteger nextBigInteger() Returns the next BigInteger value from the input Double nextDouble() Returns the next Double value from the input Float nextFloat() Returns the next Float value from the input Int nextInt() Returns the next int from the input Long nextLong() Returns the next long value from the input String nextLine() Returns the next line from the input string Short nextShort() Returns the next short value from the input string Java Scanner Exception
We can use the below methods to read different input types and other manipulations Method Description void close() Closes the scanner object Pattern delimiter() Returns the Pattern of the scanner object that it currently uses to match delimiter boolean hasNext() Returns true if there is another token in the input string. Scanner sc3 = new Scanner(String s) Scanner Methods to read different input types
The 2nd object sc1 reads input from a file and the 3rd object sc2 reads input from a string. The 1st object sc reads input data from user input which can be through the keyboard.
Scanner java how to#
The below code shows you how to create a scanner object with different input streams. To use the Java Scanner class, we import the package. In this case, it divides the string into 4 tokens “My”, “age”, “is”, “22” which uses space as a delimiter. For example, consider the below input string String s = "My age is 22" It then iterates through each token which is nothing but each data using its in-built methods. The scanner object reads the input and divides it into tokens based on a delimiter which is normally white space.
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