一些常用的字符串处理方法

在工作过程中发现经常需要对某些字符串进行处理，所以就封装了加一些常用的

package com.dbyl.libarary.utils;

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

public class StringUtils {
    /**
     * This method is for judge the string null or not null
     * 
     * @author Young
     * @param str
     * @return
     */
    public static boolean isNull(String str) {
        return (str == null ? true : false);
    }

    /**
     * This method is for judge the string is empty or not
     * 
     * @author Young
     * @param str
     * @return
     */
    public static boolean isEmpty(String str) {
        return (str.equals("") ? true : false);
    }

    /**
     * This method is for judge null or empty
     * 
     * @author Young
     * @param str
     * @return
     */
    public static boolean isNullOrEmpty(String str) {
        return (isNull(str) || isEmpty(str));
    }

    /**
     * This method is for get the matcher string
     * 
     * @author Young
     * @param source
     * @param rex
     * @return
     */
    public static String getMatch(String source, String rex) {
        Pattern pattern = Pattern.compile(rex);
        Matcher matcher = pattern.matcher(source);
        if (matcher.find()) {
            return source.substring(matcher.start(), matcher.end());
        }
        return null;

    }

    /**
     * get the match group
     * 
     * @author Young
     * @param source
     * @param rex
     * @param groupIndex
     * @return
     */
    public static String getMatchGroup(String source, String rex, int groupIndex) {
        Pattern pattern = Pattern.compile(rex);
        Matcher matcher = pattern.matcher(source);
        if (matcher.find()) {
            return matcher.group(groupIndex);
        }
        return null;

    }

    /**
     * This method is for replaceAll the string
     * 
     * @author Young
     * @param source
     * @param rex
     * @param replaceBy
     */
    public static void replaceAll(String source, String rex, String replaceBy) {
        Pattern pattern = Pattern.compile(rex);
        Matcher matcher = pattern.matcher(source);
        if (matcher.find()) {
            matcher.replaceAll(replaceBy);
        }
    }

    /**
     * This method is for judge is match 
     * @author Young
     * @param source
     * @param rex
     * @return
     */
    public static boolean isMatch(String source, String rex) {
        Pattern pattern = Pattern.compile(rex);
        Matcher matcher = pattern.matcher(source);
        return matcher.matches();
    }
}