Java replaceAll不区分大小写

Java 中replaceAll如何忽略大小写呢?
方式一:在正则表达式前面添加(?i)

@Test
public void test_replaceAll1() {
	String input = "I like Java,jAva is very easy and jaVa is so popular.";
	String replacement = "cccc";

	System.out.println(input);
	System.out.println(input.replaceAll("(?i)java", replacement));
}

 输出结果：

I like Java,jAva is very easy and jaVa is so popular.
I like cccc,cccc is very easy and cccc is so popular.

 

方式二:使用Matcher 的appendReplacement 方法

@Test
public void test_replaceAll2() {
	String input = "I like Java,jAva is very easy and jaVa is so popular.";
	String regex = "java";
	String replacement = "cccc";

	StringBuffer sb = replaceAll2(input, regex, replacement);
	System.out.println(input);
	System.out.println(sb);

}

/***
 * replaceAll,忽略大小写
 * 
 * @param input
 * @param regex
 * @param replacement
 * @return
 */
public StringBuffer replaceAll2(String input, String regex,
		String replacement) {
	Pattern p = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
	Matcher m = p.matcher(input);
	StringBuffer sb = new StringBuffer();
	boolean result = m.find();
	while (result) {
		m.appendReplacement(sb, replacement);
		result = m.find();
	}
	m.appendTail(sb);
	return sb;
}

 输出结果：

I like Java,jAva is very easy and jaVa is so popular.
I like cccc,cccc is very easy and cccc is so popular.

 

方式三:使用Matcher 的replaceAll

/*** 
 * replaceAll,忽略大小写 
 *  
 * @param input 
 * @param regex 
 * @param replacement 
 * @return 
 */  
public String replaceAll3(String input, String regex, String replacement) {  
    Pattern p = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);  
    Matcher m = p.matcher(input);  
    String result = m.replaceAll(replacement);  
    return result;  
}  

@Test  
public void test_replaceAll3() {  
    String input = "I like Java,jAva is very easy and jaVa is so popular.";  
    String regex = "java";  
    String replacement = "cccc";  

    String sb = replaceAll3(input, regex, replacement);  
    System.out.println(input);  
    System.out.println(sb);  

}  

输出结果：

I like Java,jAva is very easy and jaVa is so popular.
I like cccc,cccc is very easy and cccc is so popular.

 

参考：

http://hw1287789687.iteye.com/blog/2150897