package com.yueqian.project.common;

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

public class StringTools {
	private static Pattern linePattern = Pattern.compile("_(\\w)");
	private static Pattern humpPattern = Pattern.compile("[A-Z]");
	/**
	 * 驼峰转下划线,最后转为大写
	 * @param str
	 * @return
	 */
	public static String humpToLine(String str) {
	    Matcher matcher = humpPattern.matcher(str);
	    StringBuffer sb = new StringBuffer();
	    while (matcher.find()) {
	        matcher.appendReplacement(sb, "_" + matcher.group(0).toUpperCase());
	    }
	    matcher.appendTail(sb);
	    return sb.toString().toUpperCase();
	}

	/**
	 * 下划线转驼峰,正常输出
	 * @param str
	 * @return
	 */
	public static String lineToHump(String str) {
	    Matcher matcher = linePattern.matcher(str.toLowerCase());
	    StringBuffer sb = new StringBuffer();
	    while (matcher.find()) {
	        matcher.appendReplacement(sb, matcher.group(1).toUpperCase());
	    }
	    matcher.appendTail(sb);
	    return sb.toString();
	}
	
	/**
     * 处理null,将null的数据转为str
     * @param str
     * @return
     */
    public static String nullToStr(String str){
        if(str==null){
            return "";
        }
        return str;
    }
}