Java駝峰命名和下劃線命名轉換
阿新 • • 發佈:2018-12-02
import java.util.regex.Matcher; import java.util.regex.Pattern; /** * 駝峰命名轉換 * * @author 47475 * */ public class Tool { private static Pattern linePattern = Pattern.compile("_(\\w)"); /** * 下劃線轉駝峰 ,大寫自動轉小寫<br /> * 例如:USER_NAME->userName<br /> * USERNAME->userName<br /> * USER_NAME->userName<br /> * fParentNoLeader->fParentNoLeader * */ public static String lineToHump(String str) { /** 正則表示式寫法 */ 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(); /** 字串比較寫法 */ /* * if (str == null || "".equals(str.trim())) { return ""; } int len = * str.length(); StringBuilder sb = new StringBuilder(len); for (int i = 0; i < * len; i++) { char c = str.charAt(i); if (c == '_') { if (++i < len) { * sb.append(Character.toUpperCase(str.charAt(i))); } } else { sb.append(c); } } * return sb.toString(); */ } private static Pattern humpPattern = Pattern.compile("[A-Z]"); /** * 駝峰轉下劃線,大寫自動轉小寫<br /> * 例如: USER_NAME->user_name USERNAME->userName<br /> * f_parent_no_leader->f_parent_no_leader */ public static String humpToLine(String str) { /** 簡單寫法,效率不高 */ // return str.replaceAll("[A-Z]", "_$0").toLowerCase(); /** 正則表示式高效寫法 */ 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(); /** 字串比較寫法 */ /* * if (str == null || "".equals(str.trim())) { return ""; } int len = * str.length(); StringBuilder sb = new StringBuilder(len); for (int i = 0; i < * len; i++) { char c = str.charAt(i); if (Character.isUpperCase(c)) { * sb.append('_'); sb.append(Character.toLowerCase(c)); } else { sb.append(c); } * } return sb.toString(); */ } public static void main(String[] args) { System.out.println(lineToHump("user_name"));// userName System.out.println(humpToLine("userName"));// user_name } }