java.util.regex.Matcher.usePattern(Pattern newPattern)方法

java.util.regex.Matcher.usePattern(Pattern newPattern)方法更改此Matcher用于查找匹配项的Pattern。

声明

以下是java.util.regex.Matcher.usePattern(Pattern newPattern)方法的声明。

public Matcher usePattern(Pattern newPattern)

参数

• newPattern - 此匹配器使用的新模式。

返回值

这个匹配。

异常

IllegalArgumentException - 如果newPattern为null则抛出此异常。

示例

以下示例显示了java.util.regex.Matcher.usePattern(Pattern newPattern)方法的用法。

package com.zaixian;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class MatcherDemo {
   private static String REGEX = "(a*b)(foo)";
   private static String INPUT = "aabfooaabfooabfoob";

   public static void main(String[] args) {
      // create a pattern
      Pattern pattern = Pattern.compile(REGEX);

      // get a matcher object
      Matcher matcher = pattern.matcher(INPUT); 

      while(matcher.find()) {
         //Prints the start index of the subsequence captured by the given group.
         System.out.println("Second Capturing Group, (foo) Match String start(): "+matcher.start(1));
      }  
      matcher.reset();
      matcher.usePattern(Pattern.compile("(a*b)(foob)"));

      while(matcher.find()) {
         //Prints the start index of the subsequence captured by the given group.
         System.out.println("Second Capturing Group, (fooab) Match String start(): "+matcher.start(1));
      }  
   }
}

编译并运行上面的程序，这将产生以下结果 -

Second Capturing Group, (foo) Match String start(): 0
Second Capturing Group, (foo) Match String start(): 6
Second Capturing Group, (foo) Match String start(): 12
Second Capturing Group, (fooab) Match String start(): 12