Java正则实现EL表达式

	public static void main(String[] args) {
		
		Map map = new HashMap(2);
		map.put("name", "Jame Gosling");
		map.put("alias", "Rod Johnson");
		
		String line = "${name} did a great job, so ${alias} did.";
		
		String regex = "\\$\\{[^\\}]+\\}";
		
		Pattern p = Pattern.compile(regex);
		Matcher m = p.matcher(line);
		
		String g;
		while (m.find()) {
			g = m.group();
			g = g.substring(2, g.length() - 1);
			line = m.replaceFirst(map.get(g) + "");
			m = p.matcher(line);
		}
		System.out.println(line);
		
	}

利用分组简化代码:

	public static void main(String[] args) {   
	       
	    Map map = new HashMap(2);   
	    map.put("name", "Jame Gosling");   
	    map.put("alias", "Rod Johnson");   
	       
	    String line = "${name} did a great job, so ${alias} did.";   
	       
	    String regex = "\\$\\{([^\\}]+)\\}";   
	       
	    Pattern p = Pattern.compile(regex);   
	    Matcher m = p.matcher(line);   
	       
	    String g;   
	    while (m.find()) {   
	        g = m.group(1);   
	        line = m.replaceFirst(map.get(g) + "");   
	        m = p.matcher(line);   
	    }   
	    System.out.println(line);   
	       
	}   

输出:

Jame Gosling did a great job, so Rod Johnson did.

Java 正则去除字符串两头的空格

String username = " Rod johnson ";
//Pattern p = Pattern.compile("^[\\s]+$");
String to = username.replaceAll("^\\s+|\\s+$", "");
System.out.println(to);