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;
 2 import java.util.regex.Pattern;
 3 
 4 public class CamelAndUnderLineConverter {
 5     private static Pattern linePattern = Pattern.compile("_(\\w)");
 6 
 7     /**
 8      * 下划线转驼峰
 9      */
10     public static String lineToHump(String str) {
11         str = str.toLowerCase();
12         Matcher matcher = linePattern.matcher(str);
13         StringBuffer sb = new StringBuffer();
14         while (matcher.find()) {
15             matcher.appendReplacement(sb, matcher.group(1).toUpperCase());
16         }
17         matcher.appendTail(sb);
18         return sb.toString();
19     }
20 
21     /**
22      * 驼峰转下划线(简单写法，效率低于{@link #humpToLine2(String)})
23      */
24     public static String humpToLine(String str) {
25         return str.replaceAll("[A-Z]", "_$0").toLowerCase();
26     }
27 
28     private static Pattern humpPattern = Pattern.compile("[A-Z]");
29 
30     /**
31      * 驼峰转下划线,效率比上面高
32      */
33     public static String humpToLine2(String str) {
34         Matcher matcher = humpPattern.matcher(str);
35         StringBuffer sb = new StringBuffer();
36         while (matcher.find()) {
37             matcher.appendReplacement(sb, "_" + matcher.group(0).toLowerCase());
38         }
39         matcher.appendTail(sb);
40         return sb.toString();
41     }
42 
43     public static void main(String[] args) {
44         String lineToHump = lineToHump("f_parent_no_leader");
45         System.out.println(lineToHump);// fParentNoLeader
46         System.out.println(humpToLine(lineToHump));// f_parent_no_leader
47         System.out.println(humpToLine2(lineToHump));// f_parent_no_leader
48     }
49 }