驼峰转下划线 下划线转驼峰

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

/**
 * 驼峰转换工具
 */
public class HumpUtil {
    private static Pattern linePattern = Pattern.compile("_(\\w)");

    /**
     * 驼峰转下划线
     *
     * @param str
     * @return
     */
    public static String humpToLine(String str) {
        return str.replaceAll("[A-Z]", "_$0").toLowerCase();
    }

    /**
     * 下划线转驼峰
     *
     * @param str
     * @return
     */
    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();
    }
}