A scanner will never search more than horizon code points beyond its current position. Note that a match may be clipped by the horizon; that is, an arbitrary match result may have been different if the horizon had been larger. The scanner treats the horizon as a transparent, non-anchoring bound see Matcher. If horizon is 0 , then the horizon is ignored and this method continues to search through the input looking for the specified pattern without bound.
In this case it may buffer all of the input searching for the pattern. If horizon is negative, then an IllegalArgumentException is thrown. Parameters: pattern - the pattern to scan for Returns: the text that matched the specified pattern Throws: IllegalStateException - if this scanner is closed IllegalArgumentException - if horizon is negative skip public Scanner skip Pattern pattern Skips input that matches the specified pattern, ignoring delimiters.
This method will skip input if an anchored match of the specified pattern succeeds. If a match to the specified pattern is not found at the current position, then no input is skipped and a NoSuchElementException is thrown. Since this method seeks to match the specified pattern starting at the scanner's current position, patterns that can match a lot of input ".
Note that it is possible to skip something without risking a NoSuchElementException by using a pattern that can match nothing, e. Parameters: pattern - a string specifying the pattern to skip over Returns: this scanner Throws: NoSuchElementException - if the specified pattern is not found IllegalStateException - if this scanner is closed skip public Scanner skip String pattern Skips input that matches a pattern constructed from the specified string.
An invocation of this method of the form skip pattern behaves in exactly the same way as the invocation skip Pattern. Parameters: pattern - a string specifying the pattern to skip over Returns: this scanner Throws: IllegalStateException - if this scanner is closed hasNextBoolean public boolean hasNextBoolean Returns true if the next token in this scanner's input can be interpreted as a boolean value using a case insensitive pattern created from the string "true false".
The scanner does not advance past the input that matched. Returns: true if and only if this scanner's next token is a valid boolean value Throws: IllegalStateException - if this scanner is closed nextBoolean public boolean nextBoolean Scans the next token of the input into a boolean value and returns that value.
This method will throw InputMismatchException if the next token cannot be translated into a valid boolean value. If the match is successful, the scanner advances past the input that matched.
Returns: the boolean scanned from the input Throws: InputMismatchException - if the next token is not a valid boolean NoSuchElementException - if input is exhausted IllegalStateException - if this scanner is closed hasNextByte public boolean hasNextByte Returns true if the next token in this scanner's input can be interpreted as a byte value in the default radix using the nextByte method.
Returns: true if and only if this scanner's next token is a valid byte value Throws: IllegalStateException - if this scanner is closed hasNextByte public boolean hasNextByte int radix Returns true if the next token in this scanner's input can be interpreted as a byte value in the specified radix using the nextByte method.
Parameters: radix - the radix used to interpret the token as a byte value Returns: true if and only if this scanner's next token is a valid byte value Throws: IllegalStateException - if this scanner is closed nextByte public byte nextByte Scans the next token of the input as a byte. An invocation of this method of the form nextByte behaves in exactly the same way as the invocation nextByte radix , where radix is the default radix of this scanner.
Returns: the byte scanned from the input Throws: InputMismatchException - if the next token does not match the Integer regular expression, or is out of range NoSuchElementException - if input is exhausted IllegalStateException - if this scanner is closed nextByte public byte nextByte int radix Scans the next token of the input as a byte. This method will throw InputMismatchException if the next token cannot be translated into a valid byte value as described below.
If the translation is successful, the scanner advances past the input that matched. If the next token matches the Integer regular expression defined above then the token is converted into a byte value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via Character.
Parameters: radix - the radix used to interpret the token as a byte value Returns: the byte scanned from the input Throws: InputMismatchException - if the next token does not match the Integer regular expression, or is out of range NoSuchElementException - if input is exhausted IllegalStateException - if this scanner is closed hasNextShort public boolean hasNextShort Returns true if the next token in this scanner's input can be interpreted as a short value in the default radix using the nextShort method.
Returns: true if and only if this scanner's next token is a valid short value in the default radix Throws: IllegalStateException - if this scanner is closed hasNextShort public boolean hasNextShort int radix Returns true if the next token in this scanner's input can be interpreted as a short value in the specified radix using the nextShort method.
Parameters: radix - the radix used to interpret the token as a short value Returns: true if and only if this scanner's next token is a valid short value in the specified radix Throws: IllegalStateException - if this scanner is closed nextShort public short nextShort Scans the next token of the input as a short. An invocation of this method of the form nextShort behaves in exactly the same way as the invocation nextShort radix , where radix is the default radix of this scanner.
Returns: the short scanned from the input Throws: InputMismatchException - if the next token does not match the Integer regular expression, or is out of range NoSuchElementException - if input is exhausted IllegalStateException - if this scanner is closed nextShort public short nextShort int radix Scans the next token of the input as a short.
This method will throw InputMismatchException if the next token cannot be translated into a valid short value as described below. If the next token matches the Integer regular expression defined above then the token is converted into a short value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via Character.
Parameters: radix - the radix used to interpret the token as a short value Returns: the short scanned from the input Throws: InputMismatchException - if the next token does not match the Integer regular expression, or is out of range NoSuchElementException - if input is exhausted IllegalStateException - if this scanner is closed hasNextInt public boolean hasNextInt Returns true if the next token in this scanner's input can be interpreted as an int value in the default radix using the nextInt method.
Returns: true if and only if this scanner's next token is a valid int value Throws: IllegalStateException - if this scanner is closed hasNextInt public boolean hasNextInt int radix Returns true if the next token in this scanner's input can be interpreted as an int value in the specified radix using the nextInt method.
Parameters: radix - the radix used to interpret the token as an int value Returns: true if and only if this scanner's next token is a valid int value Throws: IllegalStateException - if this scanner is closed nextInt public int nextInt Scans the next token of the input as an int.
An invocation of this method of the form nextInt behaves in exactly the same way as the invocation nextInt radix , where radix is the default radix of this scanner. Returns: the int scanned from the input Throws: InputMismatchException - if the next token does not match the Integer regular expression, or is out of range NoSuchElementException - if input is exhausted IllegalStateException - if this scanner is closed nextInt public int nextInt int radix Scans the next token of the input as an int.
This method will throw InputMismatchException if the next token cannot be translated into a valid int value as described below. If the next token matches the Integer regular expression defined above then the token is converted into an int value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via Character.
Parameters: radix - the radix used to interpret the token as an int value Returns: the int scanned from the input Throws: InputMismatchException - if the next token does not match the Integer regular expression, or is out of range NoSuchElementException - if input is exhausted IllegalStateException - if this scanner is closed hasNextLong public boolean hasNextLong Returns true if the next token in this scanner's input can be interpreted as a long value in the default radix using the nextLong method.
Returns: true if and only if this scanner's next token is a valid long value Throws: IllegalStateException - if this scanner is closed hasNextLong public boolean hasNextLong int radix Returns true if the next token in this scanner's input can be interpreted as a long value in the specified radix using the nextLong method. Parameters: radix - the radix used to interpret the token as a long value Returns: true if and only if this scanner's next token is a valid long value Throws: IllegalStateException - if this scanner is closed nextLong public long nextLong Scans the next token of the input as a long.
An invocation of this method of the form nextLong behaves in exactly the same way as the invocation nextLong radix , where radix is the default radix of this scanner. Returns: the long scanned from the input Throws: InputMismatchException - if the next token does not match the Integer regular expression, or is out of range NoSuchElementException - if input is exhausted IllegalStateException - if this scanner is closed nextLong public long nextLong int radix Scans the next token of the input as a long.
This method will throw InputMismatchException if the next token cannot be translated into a valid long value as described below. If the next token matches the Integer regular expression defined above then the token is converted into a long value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via Character.
Parameters: radix - the radix used to interpret the token as an int value Returns: the long scanned from the input Throws: InputMismatchException - if the next token does not match the Integer regular expression, or is out of range NoSuchElementException - if input is exhausted IllegalStateException - if this scanner is closed hasNextFloat public boolean hasNextFloat Returns true if the next token in this scanner's input can be interpreted as a float value using the nextFloat method.
Returns: true if and only if this scanner's next token is a valid float value Throws: IllegalStateException - if this scanner is closed nextFloat public float nextFloat Scans the next token of the input as a float. This method will throw InputMismatchException if the next token cannot be translated into a valid float value as described below. If the next token matches the Float regular expression defined above then the token is converted into a float value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via Character.
If the token matches the localized NaN or infinity strings, then either "Nan" or "Infinity" is passed to Float. Returns: the float scanned from the input Throws: InputMismatchException - if the next token does not match the Float regular expression, or is out of range NoSuchElementException - if input is exhausted IllegalStateException - if this scanner is closed hasNextDouble public boolean hasNextDouble Returns true if the next token in this scanner's input can be interpreted as a double value using the nextDouble method.
Returns: true if and only if this scanner's next token is a valid double value Throws: IllegalStateException - if this scanner is closed nextDouble public double nextDouble Scans the next token of the input as a double. This method will throw InputMismatchException if the next token cannot be translated into a valid double value.
If the next token matches the Float regular expression defined above then the token is converted into a double value as if by removing all locale specific prefixes, group separators, and locale specific suffixes, then mapping non-ASCII digits into ASCII digits via Character.
If the token matches the localized NaN or infinity strings, then either "Nan" or "Infinity" is passed to Double. Returns: the double scanned from the input Throws: InputMismatchException - if the next token does not match the Float regular expression, or is out of range NoSuchElementException - if the input is exhausted IllegalStateException - if this scanner is closed hasNextBigInteger public boolean hasNextBigInteger Returns true if the next token in this scanner's input can be interpreted as a BigInteger in the default radix using the nextBigInteger method.
Returns: true if and only if this scanner's next token is a valid BigInteger Throws: IllegalStateException - if this scanner is closed hasNextBigInteger public boolean hasNextBigInteger int radix Returns true if the next token in this scanner's input can be interpreted as a BigInteger in the specified radix using the nextBigInteger method.
Parameters: radix - the radix used to interpret the token as an integer Returns: true if and only if this scanner's next token is a valid BigInteger Throws: IllegalStateException - if this scanner is closed nextBigInteger public BigInteger nextBigInteger Scans the next token of the input as a BigInteger. An invocation of this method of the form nextBigInteger behaves in exactly the same way as the invocation nextBigInteger radix , where radix is the default radix of this scanner.
Parameters: radix - the radix used to interpret the token Returns: the BigInteger scanned from the input Throws: InputMismatchException - if the next token does not match the Integer regular expression, or is out of range NoSuchElementException - if the input is exhausted IllegalStateException - if this scanner is closed hasNextBigDecimal public boolean hasNextBigDecimal Returns true if the next token in this scanner's input can be interpreted as a BigDecimal using the nextBigDecimal method.
Returns: the BigDecimal scanned from the input Throws: InputMismatchException - if the next token does not match the Decimal regular expression, or is out of range NoSuchElementException - if the input is exhausted IllegalStateException - if this scanner is closed reset public Scanner reset Resets this scanner.
Resetting a scanner discards all of its explicit state information which may have been changed by invocations of useDelimiter java. Pattern , useLocale java. Locale , or useRadix int. An invocation of this method of the form scanner.
That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples. Separators are one of many ways to indicate the boundaries of a data stream.
This character is called a field separator or separator. If the field separator separator is a comma, the file is in comma-separated CSV or comma-separated format. Another popular separator is the tab. The close method closes this scanner. If this scanner is already closed, calling this method has no effect. The Java Scanner class is used to collect user input.
Scanner is part of Java. IOException; import java. ArrayList; import java. But in order to specify any delimiter to separate data in a file, In that case, a Scanner will be helpful. As we can see that there are 2 strings in the first line of a file but using BufferedReader we got them as a combined string.
Note: While reading the file, if the file is in same location where the program code is saved then no need to mention path just specify the file name. If the file is in a different location with respect to the program saved location then we should specify the path along with the filename.
Using Scanner to read the file The scanner is mainly used to read data from users for primitive datatypes. But even to get data from a file Scanner can be used along with File or FileReader to load data of a file. This Scanner generally breaks the tokens into strings by a default delimiter space but even we can explicitly specify the other delimiters by using the useDelimiter method.
Below is the example code to store the content of the file in an array using Scanner. List; import java. Finally, we converted that ArrayList to Array using the toArray method. Another popular delimiter is the tab. If this scanner is already closed then invoking this method will have no effect. The Java Scanner class is used to collect user input.
Scanner is part of the java. Scanner reads text from standard input and returns it to a program. The reset method of Reader Class in Java is used to reset the stream. After reset, if the stream has been marked, then this method attempts to reposition it at the mark, else it will try to position it to the starting. The reason is that hasNext checks if there are any more non-whitespace characters available.
0コメント