java驼峰法和下划线法字符串的相互转换

java驼峰法和下划线法字符串的相互转换

 1 import java.util.regex.Matcher;
 import java.util.regex.Pattern;

 public class CamelAndUnderLineConverter {
     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
     }
 }