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 Methods

Any 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 Methods
Exception 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 Methods

Any 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 Methods
Exception 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)