AEStringUtils.java

package com.realmo.utils;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * String Utils
 *
 * @author <a href="http://www.trinea.cn" target="_blank">Trinea</a>
 */
public class AEStringUtils {

    /**
     * is null or its length is 0 or it is made by space
     *
     * <pre>
     * isBlank(null) = true;
     * isBlank(&quot;&quot;) = true;
     * isBlank(&quot;  &quot;) = true;
     * isBlank(&quot;a&quot;) = false;
     * isBlank(&quot;a &quot;) = false;
     * isBlank(&quot; a&quot;) = false;
     * isBlank(&quot;a b&quot;) = false;
     * </pre>
     *
     * @param str
     * @return if string is null or its size is 0 or it is made by space, return
     *         true, else return false.
     */
    public static boolean isBlank(String str) {
        return (str == null || str.trim().length() == 0);
    }

    /**
     * is null or its length is 0
     *
     * <pre>
     * isEmpty(null) = true;
     * isEmpty(&quot;&quot;) = true;
     * isEmpty(&quot;  &quot;) = false;
     * </pre>
     *
     * @param str
     * @return if string is null or its size is 0, return true, else return
     *         false.
     */
    public static boolean isEmpty(String str) {
        return (str == null || str.length() == 0);
    }

    /**
     * null string to empty string
     *
     * <pre>
     * nullStrToEmpty(null) = &quot;&quot;;
     * nullStrToEmpty(&quot;&quot;) = &quot;&quot;;
     * nullStrToEmpty(&quot;aa&quot;) = &quot;aa&quot;;
     * </pre>
     *
     * @param str
     * @return
     */
    public static String nullStrToEmpty(String str) {
        return (str == null ? "" : str);
    }

    /**
     * capitalize first letter
     *
     * <pre>
     * capitalizeFirstLetter(null)     =   null;
     * capitalizeFirstLetter("")       =   "";
     * capitalizeFirstLetter("2ab")    =   "2ab"
     * capitalizeFirstLetter("a")      =   "A"
     * capitalizeFirstLetter("ab")     =   "Ab"
     * capitalizeFirstLetter("Abc")    =   "Abc"
     * </pre>
     *
     * @param str
     * @return
     */
    public static String capitalizeFirstLetter(String str) {
        if (isEmpty(str)) {
            return str;
        }

        char c = str.charAt(0);
        return (!Character.isLetter(c) || Character.isUpperCase(c)) ? str
                : new StringBuilder(str.length())
                .append(Character.toUpperCase(c))
                .append(str.substring(1)).toString();
    }

    /**
     * encoded in utf-8
     *
     * <pre>
     * utf8Encode(null)        =   null
     * utf8Encode("")          =   "";
     * utf8Encode("aa")        =   "aa";
     * utf8Encode("啊啊啊啊")   = "%E5%95%8A%E5%95%8A%E5%95%8A%E5%95%8A";
     * </pre>
     *
     * @param str
     * @return
     * @throws UnsupportedEncodingException
     *             if an error occurs
     */
    public static String utf8Encode(String str) {
        if (!isEmpty(str) && str.getBytes().length != str.length()) {
            try {
                return URLEncoder.encode(str, "UTF-8");
            } catch (UnsupportedEncodingException e) {
                throw new RuntimeException(
                        "UnsupportedEncodingException occurred. ", e);
            }
        }
        return str;
    }

    /**
     * encoded in utf-8, if exception, return defultReturn
     *
     * @param str
     * @param defultReturn
     * @return
     */
    public static String utf8Encode(String str, String defultReturn) {
        if (!isEmpty(str) && str.getBytes().length != str.length()) {
            try {
                return URLEncoder.encode(str, "UTF-8");
            } catch (UnsupportedEncodingException e) {
                return defultReturn;
            }
        }
        return str;
    }

    /**
     * decode in utf-8
     *
     * <pre>
     * utf8Decoder(null)        =   null
     * utf8Decoder("")          =   "";
     * utf8Decoder("aa")        =   "aa";
     * utf8Decoder("%E5%95%8A%E5%95%8A%E5%95%8A%E5%95%8A")   = "啊啊啊啊";
     * </pre>
     *
     * @param str
     * @return
     * @throws UnsupportedEncodingException
     *             if an error occurs
     */
    public static String utf8Decoder(String str){
        if (!isEmpty(str) && str.getBytes().length != str.length()) {
            try {
                return URLDecoder.decode(str, "UTF-8");
            } catch (UnsupportedEncodingException e) {
                throw new RuntimeException(
                        "UnsupportedEncodingException occurred. ", e);
            }
        }
        return str;
    }

    /**
     * get innerHtml from href
     *
     * <pre>
     * getHrefInnerHtml(null)                                  = ""
     * getHrefInnerHtml("")                                    = ""
     * getHrefInnerHtml("mp3")                                 = "mp3";
     * getHrefInnerHtml("&lt;a innerHtml&lt;/a&gt;")                    = "&lt;a innerHtml&lt;/a&gt;";
     * getHrefInnerHtml("&lt;a&gt;innerHtml&lt;/a&gt;")                    = "innerHtml";
     * getHrefInnerHtml("&lt;a&lt;a&gt;innerHtml&lt;/a&gt;")                    = "innerHtml";
     * getHrefInnerHtml("&lt;a href="baidu.com"&gt;innerHtml&lt;/a&gt;")               = "innerHtml";
     * getHrefInnerHtml("&lt;a href="baidu.com" title="baidu"&gt;innerHtml&lt;/a&gt;") = "innerHtml";
     * getHrefInnerHtml("   &lt;a&gt;innerHtml&lt;/a&gt;  ")                           = "innerHtml";
     * getHrefInnerHtml("&lt;a&gt;innerHtml&lt;/a&gt;&lt;/a&gt;")                      = "innerHtml";
     * getHrefInnerHtml("jack&lt;a&gt;innerHtml&lt;/a&gt;&lt;/a&gt;")                  = "innerHtml";
     * getHrefInnerHtml("&lt;a&gt;innerHtml1&lt;/a&gt;&lt;a&gt;innerHtml2&lt;/a&gt;")        = "innerHtml2";
     * </pre>
     *
     * @param href
     * @return <ul>
     *         <li>if href is null, return ""</li>
     *         <li>if not match regx, return source</li>
     *         <li>return the last string that match regx</li>
     *         </ul>
     */
    public static String getHrefInnerHtml(String href) {
        if (isEmpty(href)) {
            return "";
        }

        String hrefReg = ".*<[\\s]*a[\\s]*.*>(.+?)<[\\s]*/a[\\s]*>.*";
        Pattern hrefPattern = Pattern
                .compile(hrefReg, Pattern.CASE_INSENSITIVE);
        Matcher hrefMatcher = hrefPattern.matcher(href);
        if (hrefMatcher.matches()) {
            return hrefMatcher.group(1);
        }
        return href;
    }

    /**
     * process special char in html
     *
     * <pre>
     * htmlEscapeCharsToString(null) = null;
     * htmlEscapeCharsToString("") = "";
     * htmlEscapeCharsToString("mp3") = "mp3";
     * htmlEscapeCharsToString("mp3&lt;") = "mp3<";
     * htmlEscapeCharsToString("mp3&gt;") = "mp3\>";
     * htmlEscapeCharsToString("mp3&amp;mp4") = "mp3&mp4";
     * htmlEscapeCharsToString("mp3&quot;mp4") = "mp3\"mp4";
     * htmlEscapeCharsToString("mp3&lt;&gt;&amp;&quot;mp4") = "mp3\<\>&\"mp4";
     * </pre>
     *
     * @param source
     * @return
     */
    public static String htmlEscapeCharsToString(String source) {
        return AEStringUtils.isEmpty(source) ? source : source
                .replaceAll("&lt;", "<").replaceAll("&gt;", ">")
                .replaceAll("&amp;", "&").replaceAll("&quot;", "\"");
    }

    /**
     * transform half width char to full width char
     *
     * <pre>
     * fullWidthToHalfWidth(null) = null;
     * fullWidthToHalfWidth("") = "";
     * fullWidthToHalfWidth(new String(new char[] {12288})) = " ";
     * fullWidthToHalfWidth("！＂＃＄％＆) = "!\"#$%&";
     * </pre>
     *
     * @param s
     * @return
     */
    public static String fullWidthToHalfWidth(String s) {
        if (isEmpty(s)) {
            return s;
        }

        char[] source = s.toCharArray();
        for (int i = 0; i < source.length; i++) {
            if (source[i] == 12288) {
                source[i] = ' ';
                // } else if (source[i] == 12290) {
                // source[i] = '.';
            } else if (source[i] >= 65281 && source[i] <= 65374) {
                source[i] = (char) (source[i] - 65248);
            } else {
                source[i] = source[i];
            }
        }
        return new String(source);
    }

    /**
     * transform full width char to half width char
     *
     * <pre>
     * halfWidthToFullWidth(null) = null;
     * halfWidthToFullWidth("") = "";
     * halfWidthToFullWidth(" ") = new String(new char[] {12288});
     * halfWidthToFullWidth("!\"#$%&) = "！＂＃＄％＆";
     * </pre>
     *
     * @param s
     * @return
     */
    public static String halfWidthToFullWidth(String s) {
        if (isEmpty(s)) {
            return s;
        }

        char[] source = s.toCharArray();
        for (int i = 0; i < source.length; i++) {
            if (source[i] == ' ') {
                source[i] = (char) 12288;
                // } else if (source[i] == '.') {
                // source[i] = (char)12290;
            } else if (source[i] >= 33 && source[i] <= 126) {
                source[i] = (char) (source[i] + 65248);
            } else {
                source[i] = source[i];
            }
        }
        return new String(source);
    }



    public static String escape(String src) {
        int i;
        char j;
        StringBuffer tmp = new StringBuffer();
        tmp.ensureCapacity(src.length() * 6);
        for (i = 0; i < src.length(); i++) {
            j = src.charAt(i);
            if (Character.isDigit(j) || Character.isLowerCase(j)
                    || Character.isUpperCase(j))
                tmp.append(j);
            else if (j < 256) {
                tmp.append("%");
                if (j < 16)
                    tmp.append("0");
                tmp.append(Integer.toString(j, 16));
            } else {
                tmp.append("%u");
                tmp.append(Integer.toString(j, 16));
            }
        }
        return tmp.toString();
    }

    public static String unescape(String src) {
        StringBuffer tmp = new StringBuffer();
        tmp.ensureCapacity(src.length());
        int lastPos = 0, pos = 0;
        char ch;
        while (lastPos < src.length()) {
            pos = src.indexOf("%", lastPos);
            if (pos == lastPos) {
                if (src.charAt(pos + 1) == 'u') {
                    ch = (char) Integer.parseInt(
                            src.substring(pos + 2, pos + 6), 16);
                    tmp.append(ch);
                    lastPos = pos + 6;
                } else {
                    ch = (char) Integer.parseInt(
                            src.substring(pos + 1, pos + 3), 16);
                    tmp.append(ch);
                    lastPos = pos + 3;
                }
            } else {
                if (pos == -1) {
                    tmp.append(src.substring(lastPos));
                    lastPos = src.length();
                } else {
                    tmp.append(src.substring(lastPos, pos));
                    lastPos = pos;
                }
            }
        }
        return tmp.toString();
    }


}