Pattern & Matcher

Pattern pattern=Pattern.compile("java");
		Matcher matcher=pattern.matcher(" java Java JaVa  JAVA  jAva  iiidd");
		while (matcher.find())
		{
			System.out.println(matcher.group()+":start->end:"+matcher.start()+"->"+matcher.end());
		}

结果
java:start->end:1->5
此时只能匹配第一个java

若要匹配大小写不分 需要compile方法的另外一个重载方法

Pattern pattern=Pattern.compile("java",Pattern.CASE_INSENSITIVE);
		Matcher matcher=pattern.matcher(" java Java JaVa  JAVA  jAva  iiidd");
		while (matcher.find())
		{
			System.out.println(matcher.group()+":start->end:"+matcher.start()+"->"+matcher.end());
		}

结果
java:start->end:1->5
Java:start->end:6->10
JaVa:start->end:11->15
JAVA:start->end:17->21
jAva:start->end:23->27

3 把奇数位置的匹配值替换成JAVA 偶数的替换成Java

	
		Pattern pattern=Pattern.compile("java" ,Pattern.CASE_INSENSITIVE);
		Matcher matcher=pattern.matcher(" java Java JaVa  JAVA  jAva  iiidd");
		StringBuffer buffer=new StringBuffer();
		 int i=0;
		while (matcher.find())
		{
			i++;
			if(i%2==0)
			{
				matcher.appendReplacement(buffer, "JAVA");
			}
			else {
				matcher.appendReplacement(buffer, "java");
			}
		}
		matcher.appendTail(buffer);
		System.out.println(buffer);

结果
  java JAVA java  JAVA  java  iiidd

matcher.appendTail(buffer);是将匹配的剩下的尾巴append到StringBuffer的末尾