String操作助手类(原创)

/**
 * String操作助手类
 * 
 * @author FiliRon
 * @see
 */
public final class StringHelper {
 /**
  * 判断字符串是否为null,或者""。
  * 
  * @param str
  * @return
  */
 public static boolean isNullString(String str) {
  return (str == null || "".equals(str)) ? true : false;
 }

 /**
  * 首字母大写
  * 
  * @param source
  * @return
  */
 public static String upperFirstChar(String source) {
  if (source == null || "".equals(source)) {
   return source;
  }
  String firstChar = source.substring(0, 1);
  return firstChar.toUpperCase() + source.substring(1);
 }

 /**
  * 将输入串进行XML编码,主要替换的字符如下:

  * "&" ==> "&" 
 "<" ==> "<" 

  * ">" ==> ">" 

  * """ ==> """ 

  * "'" ==> "'" 

  * 
  * @param s_string
  *            输入串
  * @return XML编码后的串
  */
 public static String encodedXml(String s_string) {
  if (s_string == null) {
   return "";
  }
  s_string = replaceStr(s_string, "&", "&");
  s_string = replaceStr(s_string, "<", "<");
  s_string = replaceStr(s_string, ">", ">");
  s_string = replaceStr(s_string, "转义符"", """);
  s_string = replaceStr(s_string, "'", "'");
  return s_string;
 }

 /**
  * 把源字符串中的oldString以newString来替换掉,如果oldString为null或空则返回源字符串,如果newString为null则认为空
  * 
  * @param source
  *            源字符串
  * @param oldString
  *            被替换的字符串
  * @param newString
  *            新的字符串
  * @return 替换后的字符串
  */
 public static String replaceStr(String source, String oldString,
   String newString) {
  if (oldString == null || oldString.length() == 0) {
   return source;
  }
  if (source == null) {
   return "";
  }
  if (newString == null) {
   newString = "";
  }

  StringBuffer output = new StringBuffer();
  int lengthOfSource = source.length();
  int lengthOfOld = oldString.length();
  int posStart = 0;
  int pos;
  while ((pos = source.indexOf(oldString, posStart)) >= 0) {
   output.append(source.substring(posStart, pos));
   output.append(newString);
   posStart = pos + lengthOfOld;
  }
  if (posStart < lengthOfSource) {
   output.append(source.substring(posStart));
  }
  return output.toString();
 }
}