java常用字符串操作函數

/**


分割字符串
*
@param str String 原始字符串
@param splitsign String 分隔符
@return String[] 分割后的字符串數組
*/
@SuppressWarnings("unchecked")
public static String[] split(String str, String splitsign) {
int index;
if (str == null || splitsign == null)
 return null;
ArrayList al = new ArrayList();
while ((index = str.indexOf(splitsign)) != -1) {
 al.add(str.substring(0, index));
 str = str.substring(index + splitsign.length());
}
al.add(str);
return (String[]) al.toArray(new String[0]);
}

/**

替換字符串
*
@param from String 原始字符串
@param to String 目標字符串
@param source String 母字符串
@return String 替換后的字符串
*/
public static String replace(String from, String to, String source) {
if (source == null || from == null || to == null)
 return null;
StringBuffer bf = new StringBuffer("");
int index = -1;
while ((index = source.indexOf(from)) != -1) {
 bf.append(source.substring(0, index) + to);
 source = source.substring(index + from.length());
 index = source.indexOf(from);
}
bf.append(source);
return bf.toString();
}

/**

替換字符串，能能夠在HTML頁面上直接顯示(替換雙引號和小于號)
*
@param str String 原始字符串
@return String 替換后的字符串
*/
public static String htmlencode(String str) {
if (str == null) {
 return null;
}
return replace("\"", """, replace("<", "<", str));
}


/**

替換字符串，將被編碼的轉換成原始碼（替換成雙引號和小于號）
*
@param str String
@return String
*/
public static String htmldecode(String str) {
if (str == null) {
 return null;
}
return replace(""", "\"", replace("<", "<", str));
}


private static final String _BR = "<br/>";
/**

在頁面上直接顯示文本內容，替換小于號，空格，回車，TAB
*
@param str String 原始字符串
@return String 替換后的字符串
*/
public static String htmlshow(String str) {
if (str == null) {
 return null;
}
str = replace("<", "<", str);
str = replace(" ", " ", str);
str = replace("\r\n", _BR, str);
str = replace("\n", _BR, str);
str = replace("\t", "    ", str);
return str;
}


/**

返回指定字節長度的字符串
*
@param str String 字符串
@param length int 指定長度
@return String 返回的字符串
*/
public static String toLength(String str, int length) {
if (str == null) {
 return null;
}
if (length <= 0) {
 return "";
}
try {
 if (str.getBytes("GBK").length <= length) {
   return str;
 }
} catch (Exception ex) {
}
StringBuffer buff = new StringBuffer();
int index = 0;
char c;
length -= 3;
while (length > 0) {
 c = str.charAt(index);
 if (c < 128) {
   length--;
 } else {
   length--;
   length--;
 }
 buff.append(c);
 index++;
}
buff.append("...");
return buff.toString();
}


/**

判斷是否為整數
*
@param str 傳入的字符串
@return 是整數返回true,否則返回false
/
public static boolean isInteger(String str) {
Pattern pattern = Pattern.compile("^[-\\+]?[\\d]$");
return pattern.matcher(str).matches();
}

/**

判斷是否為浮點數，包括double和float
*
@param str 傳入的字符串
@return 是浮點數返回true,否則返回false
/
public static boolean isDouble(String str) {
Pattern pattern = Pattern.compile("^[-\\+]?[.\\d]$");
return pattern.matcher(str).matches();
}

/**

判斷輸入的字符串是否符合Email樣式.
*
@param str 傳入的字符串
@return 是Email樣式返回true,否則返回false
/
public static boolean isEmail(String str) {
Pattern pattern = Pattern.compile("^\\w+([-+.]\\w+)@\\w+([-.]\\w+)\\.\\w+([-.]\\w+)$");
return pattern.matcher(str).matches();
}

/**

判斷輸入的字符串是否為純漢字
*
@param str 傳入的字符竄
@return 如果是純漢字返回true,否則返回false
*/
public static boolean isChinese(String str) {
Pattern pattern = Pattern.compile("[\u0391-\uFFE5]+$");
return pattern.matcher(str).matches();
}

/**

是否為空白,包括null和""
*
@param str
@return
*/
public static boolean isBlank(String str) {
return str == null || str.trim().length() == 0;
}

/**

判斷是不是合法手機
handset 手機號碼
*/
public static boolean isHandset(String handset) {
try {
 if(!handset.substring(0,1).equals("1")) {
  return false;
 }
 if (handset==null || handset.length()!=11) {
  return false;
 }
 String check = "^[0123456789]+$";
 Pattern regex = Pattern.compile(check);
 Matcher matcher = regex.matcher(handset);
 boolean isMatched = matcher.matches();
 if(isMatched) {
  return true;
 } else {
  return false;
 }
} catch (RuntimeException e) {
 return false;
}
}
}</pre>