java,下划线与驼峰命名转换

下划线与驼峰命名转换

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
}
}

不纠结""_"+matcher.group(0).toLowerCase()"的话，humpToLine2效率会比humpToLine高一些，看String#replaceAll方法源码即可。