关于java正则表达式非捕获型括号和捕获型括号的研究

        今天在做一个正则表达式的解析时，突然看见一个？：的例子，就看不懂了，然后在网上查了下，竟然是非捕获型括号，意思就是匹配pattern，但不包含在match的group方法里面。

        (?:  pattern)是非捕获型括号  匹配pattern，但不捕获匹配结果。
        (pattern )是捕获型括号。  匹配pattern，匹配pattern并捕获结果,自动获取组号

深入了解还得看例子：

例一：

@Testpublic void test9(){Pattern p = Pattern.compile("(\\d+,)(\\w+)");String s = "123,abc-78,def";Matcher m = p.matcher(s);while(m.find()){  System.out.println("m.group():"+m.group()); //打印所有  System.out.println("m.group(1):"+m.group(0)); //打印所有  System.out.println("m.group(1):"+m.group(1)); //打印数字的  System.out.println("m.group(2):"+m.group(2)); //打印字母的}}

输出：

m.group():123,abc
m.group(1):123,abc
m.group(1):123,
m.group(2):abc
m.group():78,def
m.group(1):78,def
m.group(1):78,
m.group(2):def

 

例二：

@Testpublic void test10(){Pattern p = Pattern.compile("(\\d+)-(\\d+)-(\\d+)\\s+([A-z]+)\\s+([A-z]+)\\s+(\\d+):(\\d+)");String s = "2013-10-26 wei test 15:39";Matcher m = p.matcher(s);if(m.find()){System.out.println(m.groupCount());System.out.println("m.group():"+m.group()); //2013-10-26 wei test 15:39System.out.println("m.group():"+m.group(0)); //2013-10-26 wei test 15:39System.out.println("m.group(1):"+m.group(1)); //2013System.out.println("m.group(2):"+m.group(2)); //10System.out.println("m.group(3):"+m.group(3)); //26System.out.println("m.group(4):"+m.group(4)); //weiSystem.out.println("m.group(5):"+m.group(5)); //testSystem.out.println("m.group(6):"+m.group(6)); //15System.out.println("m.group(7):"+m.group(7)); //39}}

 

例三：

@Testpublic void test11(){Pattern p = Pattern.compile("((\\d+)-(\\d+)-(\\d+))\\s+([A-z]+)\\s+([A-z]+)\\s+((\\d+):(\\d+))");String s = "2013-10-26 wei test 15:39";Matcher m = p.matcher(s);if(m.find()){System.out.println("m.group():"+m.group()); //2013-10-26 wei test 15:39System.out.println("m.group():"+m.group(0)); //2013-10-26 wei test 15:39System.out.println("m.group(1):"+m.group(1)); //2013-10-26System.out.println("m.group(2):"+m.group(2)); //2013System.out.println("m.group(3):"+m.group(3)); //10System.out.println("m.group(4):"+m.group(4)); //26System.out.println("m.group(5):"+m.group(5)); //weiSystem.out.println("m.group(6):"+m.group(6)); //testSystem.out.println("m.group(7):"+m.group(7)); //15:39System.out.println("m.group(8):"+m.group(8)); //15System.out.println("m.group(9):"+m.group(9)); //39}}

例四：

@Testpublic void test12(){Pattern p = Pattern.compile("((?:\\d+)-(\\d+)-(\\d+))\\s+([A-z]+)\\s+([A-z]+)\\s+((\\d+):(\\d+))");String s = "2013-10-26 wei test 15:39";Matcher m = p.matcher(s);if(m.find()){System.out.println(m.groupCount());//8System.out.println("m.group():"+m.group()); //2013-10-26 wei test 15:39System.out.println("m.group():"+m.group(0)); //2013-10-26 wei test 15:39System.out.println("m.group(1):"+m.group(1)); //2013-10-26System.out.println("m.group(2):"+m.group(2)); //10System.out.println("m.group(3):"+m.group(3)); //26System.out.println("m.group(4):"+m.group(4)); //weiSystem.out.println("m.group(5):"+m.group(5)); //testSystem.out.println("m.group(6):"+m.group(6)); //15:39System.out.println("m.group(7):"+m.group(7)); //15System.out.println("m.group(8):"+m.group(8)); //39}}

例五：

@Testpublic void test13(){Pattern p = Pattern.compile("(?:(?:\\d+)-(\\d+)-(\\d+))\\s+([A-z]+)\\s+([A-z]+)\\s+((\\d+):(\\d+))");String s = "2013-10-26 wei test 15:39";Matcher m = p.matcher(s);if(m.find()){System.out.println(m.groupCount());//7System.out.println("m.group():"+m.group()); //2013-10-26 wei test 15:39System.out.println("m.group():"+m.group(0)); //2013-10-26 wei test 15:39System.out.println("m.group(1):"+m.group(1)); //10System.out.println("m.group(2):"+m.group(2)); //26System.out.println("m.group(3):"+m.group(3)); //weiSystem.out.println("m.group(4):"+m.group(4)); //testSystem.out.println("m.group(5):"+m.group(5)); //15:39System.out.println("m.group(6):"+m.group(6)); //15System.out.println("m.group(7):"+m.group(7)); //39}}