Java replaceAll不区分大小写

缺乏、安全感 2022-04-12 10:01 347阅读 0赞

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][http_hw1287789687.iteye.com_blog_2150897]

[http_hw1287789687.iteye.com_blog_2150897]: http://hw1287789687.iteye.com/blog/2150897