Java Scanner match()方法及示例

java.util.Scanner 类的 match() 方法返回该扫描器最后一次执行的扫描操作的匹配结果。

语法

public MatchResult match()

返回值 ：该函数返回最后一次匹配操作的匹配结果。

异常 ：如果没有进行过匹配，或者最后一次匹配不成功，该函数会抛出IllegalStateException。

下面的程序说明了上述函数。

程序1 :

// Java program to illustrate the
// match() method of Scanner class in Java
// without parameter
  
import java.util.*;
  
public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {
  
        String s = "GFG Geeks!";
  
        // create a new scanner
        // with the specified String Object
        Scanner scanner = new Scanner(s);
  
        // check if next token is "GFG"
        System.out.println("" + scanner.hasNext("GFG"));
  
        // find the last match and print it
        System.out.println("" + scanner.match());
  
        // print the line
        System.out.println("" + scanner.nextLine());
  
        // close the scanner
        scanner.close();
    }
}

输出:

true
java.util.regex.Matcher[pattern=GFG region=0, 10 lastmatch=GFG]
GFG Geeks!

程序2： 演示IllegalStateException

// Java program to illustrate the
// match() method of Scanner class in Java
// without parameter
  
import java.util.*;
  
public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {
  
        try {
  
            String s = "GFG Geeks!";
  
            // create a new scanner
            // with the specified String Object
            Scanner scanner = new Scanner(s);
  
            // check if next token is "gopal"
            System.out.println("" + scanner.hasNext("gopal"));
  
            // find the last match and print it
            System.out.println("" + scanner.match());
  
            // print the line
            System.out.println("" + scanner.nextLine());
  
            // close the scanner
            scanner.close();
        }
  
        catch (IllegalStateException e) {
            System.out.println("Exception caught is: " + e);
        }
    }
}

输出:

false
Exception caught is: java.lang.IllegalStateException: No match result available

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