Java Scanner findInLine()方法及例子

findInLine(Pattern pattern)

java.util.Scanner 类的 findInLine(Pattern pattern) 方法试图找到指定模式的下一个出现点，而忽略分隔符。如果在下一个行的分隔符之前发现了该模式，扫描器将前进到匹配的输入，并返回与该模式匹配的字符串。如果在下一个分隔符之前的输入中没有检测到这样的模式，那么将返回null，扫描器的位置不变。

语法

public String findInLine(Pattern pattern)

参数： 该函数接受一个强制性参数Pattern，即扫描的模式。

返回值： 该函数返回扫描器的定界模式。

异常： 如果这个扫描器被关闭，该函数会抛出一个IllegalStateException。

下面的程序说明了上述函数。

程序1 :

// Java program to illustrate the// findInLine() method of Scanner class in Java  import java.util.*;import java.util.regex.Pattern;  public class GFG1 {    public static void main(String[] argv)        throws Exception    {          try {              // Get the string to be searched            String s = "Geeksforgeeks has Scanner Class Methods";              // Print the string            System.out.println("Target String:\n" + s);              // create a new scanner            // with the specified String Object            Scanner scanner = new Scanner(s);              // finds a pattern of any 5 letter plus "for"            System.out.println("\nAny 5 letter plus for : "                               + scanner.findInLine(                                     Pattern.compile(".....for")));              // close the scanner            scanner.close();        }        catch (IllegalStateException e) {            System.out.println("Exception thrown : " + e);        }    }}

输出:

Target String:Geeksforgeeks has Scanner Class MethodsAny 5 letter plus for : Geeksfor

程序2： 演示 IllegalStateException

// Java program to illustrate the// findInLine() method of Scanner class in Java  import java.util.*;import java.util.regex.Pattern;  public class GFG1 {    public static void main(String[] argv)        throws Exception    {          try {              // Get the string to be searched            String s = "Geeksforgeeks has Scanner Class Methods";              // Print the string            System.out.println("Target String:\n" + s);              // create a new scanner            // with the specified String Object            Scanner scanner = new Scanner(s);              // close the scanner            scanner.close();              // finds a pattern of any 5 letter plus "for"            System.out.println("\nAny 5 letter plus for : "                               + scanner.findInLine(                                     Pattern.compile(".....for")));              // print the next line of the string            System.out.println("" + scanner.nextLine());        }        catch (IllegalStateException e) {            System.out.println("Exception thrown: " + e);        }    }}

输出:

Target String:Geeksforgeeks has Scanner Class MethodsException thrown: java.lang.IllegalStateException: Scanner closed

findInLine(String pattern)

java.util.Scanner 类的 findInLine(String pattern) 方法试图找到由指定的字符串模式构建的模式的下一次出现，忽略了分隔符。

语法

public String findInLine(String pattern)

参数： 该函数接受一个被扫描的强制性参数字符串模式。

返回值： 该函数返回扫描仪的定界模式。

异常： 如果这个扫描器被关闭，该函数会抛出一个IllegalStateException。

下面的程序说明了上述函数。

程序1 :

// Java program to illustrate the// findInLine() method of Scanner class in Java  import java.util.*;import java.util.regex.Pattern;  public class GFG1 {    public static void main(String[] argv)        throws Exception    {          try {              // Get the string to be searched            String s = "Geeksforgeeks has Scanner Class Methods";              // Print the string            System.out.println("Target String:\n" + s);              // create a new scanner            // with the specified String Object            Scanner scanner = new Scanner(s);              // finds a pattern of any 5 letter plus "for"            System.out.println("\nAny 5 letter plus for : "                               + scanner.findInLine(                                     Pattern.compile(".....for")));              // close the scanner            scanner.close();        }          catch (IllegalStateException e) {            System.out.println("Exception thrown : " + e);        }    }}

输出:

Target String:Geeksforgeeks has Scanner Class MethodsAny 5 letter plus for : Geeksfor

程序2： 演示 IllegalStateException

// Java program to illustrate the// findInLine() method of Scanner class in Java  import java.util.*;import java.util.regex.Pattern;  public class GFG1 {    public static void main(String[] argv)        throws Exception    {          try {              // Get the string to be searched            String s = "Geeksforgeeks has Scanner Class Methods";              // Print the string            System.out.println("Target String:\n" + s);              // create a new scanner            // with the specified String Object            Scanner scanner = new Scanner(s);              // close the scanner            scanner.close();              // finds a pattern of any 5 letter plus "for"            System.out.println("\nAny 5 letter plus for : "                               + scanner.findInLine(                                     Pattern.compile(".....for")));        }          catch (IllegalStateException e) {            System.out.println("Exception thrown : " + e);        }    }}

输出:

Target String:Geeksforgeeks has Scanner Class MethodsException thrown : java.lang.IllegalStateException: Scanner closed

参考资料： https://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html#findInLine(java.util.regex.Pattern)