大驼峰-小驼峰-下划线互转以及首字母大、小写工具类

 自己写的大小驼峰和下划线互转工具类，使用中有问题的话希望大家可以给我评论反馈一下，我继续改进。

/**
 * String工具
 *
 * @author 随风
 */
public class WordTransformUtil {

    /**
     * 定义下划线
     */
    private static final char UNDERLINE = '_';

    public enum Camel{

        bigCamel(2,"大驼峰"),
        smallCamel(1,"小驼峰");

        final Integer type;
        final String message;

        Camel(Integer type, String message) {
            this.type = type;
            this.message = message;
        }
    }

    /**
     * 驼峰转下划线工具
     */
    public static String camelToUnderline(String param) {
        if (isNotBlank(param)) {
            int len = param.length();
            StringBuilder sb = new StringBuilder(len);
            if (Character.isUpperCase(param.charAt(0))) {
                sb.append(Character.toLowerCase(param.charAt(0)));
            } else {
                sb.append(param.charAt(0));
            }
            for (int i = 1; i < len; i++) {
                char c = param.charAt(i);
                if (Character.isUpperCase(c)) {
                    sb.append(UNDERLINE);
                    sb.append(Character.toLowerCase(c));
                } else {
                    sb.append(c);
                }
            }
            return sb.toString();
        } else {
            return "";
        }
    }

    private static boolean isBlank(CharSequence cs) {
        int strLen;
        if (cs != null && (strLen = cs.length()) != 0) {
            for (int i = 0; i < strLen; ++i) {
                if (!Character.isWhitespace(cs.charAt(i))) {
                    return false;
                }
            }
            return true;
        } else {
            return true;
        }
    }

    private static boolean isNotBlank(CharSequence cs) {
        return !isBlank(cs);
    }


    /**
     * 下划线转驼峰工具
     */
    public static String underlineToCamel(String param, Camel camel) {
        if (isNotBlank(param)) {
            int len = param.length();
            StringBuilder sb = new StringBuilder(len);
            for (int i = 0; i < len; i++) {
                char c = param.charAt(i);
                if (c == 95) {
                    ++i;
                    if (i < len) {
                        sb.append(Character.toUpperCase(param.charAt(i)));
                    }
                } else {
                    sb.append(c);
                }
            }
            char firstChar = sb.charAt(0);
            if (camel.type == 2) {
                if (Character.isLowerCase(firstChar)) {
                    sb.replace(0, 1, String.valueOf(Character.toUpperCase(firstChar)));
                }
            } else if (camel.type == 1) {
                if (Character.isUpperCase(firstChar)) {
                    sb.replace(0, 1, String.valueOf(Character.toLowerCase(firstChar)));
                }
            }
            return sb.toString();
        } else {
            return "";
        }
    }

    /**
     * 下划线转驼峰工具,默认小驼峰
     */
    public static String underlineToCamel(String param) {
        if (isNotBlank(param)) {
            int len = param.length();
            StringBuilder sb = new StringBuilder(len);
            for (int i = 0; i < len; i++) {
                char c = param.charAt(i);
                if (c == 95) {
                    ++i;
                    if (i < len) {
                        sb.append(Character.toUpperCase(param.charAt(i)));
                    }
                } else {
                    sb.append(c);
                }
            }
            char firstChar = sb.charAt(0);
            if (Character.isUpperCase(firstChar)) {
                sb.replace(0, 1, String.valueOf(Character.toLowerCase(firstChar)));
            }
            return sb.toString();
        } else {
            return "";
        }
    }

    //首字母转小写
    public static String toLowerCaseFirstOne(String s) {
        if (Character.isLowerCase(s.charAt(0))) {
            return s;
        } else {
            return Character.toLowerCase(s.charAt(0)) + s.substring(1);
        }
    }

    //首字母转大写
    public static String toUpperCaseFirstOne(String s) {
        if (Character.isUpperCase(s.charAt(0))) {
            return s;
        } else {
            return Character.toUpperCase(s.charAt(0)) + s.substring(1);
        }
    }
}