java下划线与驼峰命名互转

asfx站长

2021.07.12 15:17:19 阅读 1351

```
public class Tool {
	private static Pattern linePattern = Pattern.compile("_(\\w)");
 
	/** 下划线转驼峰 */
	public static String lineToHump(String str) {
		str = str.toLowerCase();
		Matcher matcher = linePattern.matcher(str);
		StringBuffer sb = new StringBuffer();
		while (matcher.find()) {
			matcher.appendReplacement(sb, matcher.group(1).toUpperCase());
		}
		matcher.appendTail(sb);
		return sb.toString();
	}
 
	/** 驼峰转下划线(简单写法，效率低于{@link #humpToLine2(String)}) */
	public static String humpToLine(String str) {
		return str.replaceAll("[A-Z]", "_$0").toLowerCase();
	}
 
	private static Pattern humpPattern = Pattern.compile("[A-Z]");
 
	/** 驼峰转下划线,效率比上面高 */
	public static String humpToLine2(String str) {
		Matcher matcher = humpPattern.matcher(str);
		StringBuffer sb = new StringBuffer();
		while (matcher.find()) {
			matcher.appendReplacement(sb, "_" + matcher.group(0).toLowerCase());
		}
		matcher.appendTail(sb);
		return sb.toString();
	}
 
	public static void main(String[] args) {
		String lineToHump = lineToHump("f_parent_no_leader");
		System.out.println(lineToHump);// fParentNoLeader
		System.out.println(humpToLine(lineToHump));// f_parent_no_leader
		System.out.println(humpToLine2(lineToHump));// f_parent_no_leader
	}
}

```