Java中的扫描仪 findInLine() 方法及示例

findInLine（模式模式）

Java.util.Scanner类的findInLine(Pattern pattern)方法尝试查找指定模式忽略分隔符的下一个匹配项。如果在下一行分隔符之前找到该模式，则扫描程序会越过匹配的输入并返回与该模式匹配的字符串。如果在直到下一行分隔符的输入中没有检测到这样的模式，则返回 null 并且扫描仪的位置不变。

句法：

public String findInLine(Pattern pattern)

参数：该函数接受一个强制参数Pattern pattern ，它是被扫描的模式。

返回值：该函数返回扫描仪的分隔模式。

异常：如果此扫描仪关闭，该函数将引发IllegalStateException 。

下面的程序说明了上述函数：

方案一：

// 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

方案二：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（字符串模式）

java.util.Scanner类的findInLine(String pattern)方法尝试查找从指定字符串模式构造的模式的下一个匹配项，忽略分隔符。

句法：

public String findInLine(String pattern)

参数：该函数接受扫描的强制参数字符串模式。

返回值：该函数返回扫描仪的分隔模式。

异常：如果此扫描仪关闭，该函数将引发IllegalStateException 。

下面的程序说明了上述函数：

方案一：

// 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

方案二：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： https: Java Java.util.regex.Pattern)