转义字符，将正则的关键字转义

@param c 字符
@return 转义后的文本
491320
public static String escape(char c) {
		final StringBuilder builder = new StringBuilder();
		if (RE_KEYS.contains(c)) {
			builder.append('\\');
		}
		builder.append(c);
		return builder.toString();
	}
31356
public static boolean isNumber(char c){
        //大部分字符在这个范围
        if(c > '9' && c < '０'){
            return false;
        }
        if(c < '0'){
            return false;
        }
        if(c > '９'){
            return false;
        }
        return true;
    }
940975
public static String getCellValue(Cell c) {
        String o;
        switch (c.getCellTypeEnum()) {
            case BLANK:
                o = "";
                break;
            case BOOLEAN:
                o = String.valueOf(c.getBooleanCellValue());
                break;
            case FORMULA:
                o = calculationFormula(c);
                break;
            case NUMERIC:
                if (DateUtil.isCellDateFormatted(c)) {
                    o = DateUtils.date2Str(c.getDateCellValue());
                } else {
                    o = String.valueOf(c.getNumericCellValue());
                    o = matchDoneBigDecimal(o);
                    o = RegularUtils.converNumByReg(o);
                }
                break;
            case STRING:
                o = c.getStringCellValue();
                break;
            default:
                o = null;
                break;
        }
        return o;
    }
834129
public int[] getMetricsTT(int c) {
        if (cmapExt != null)
            return (int[])cmapExt.get(Integer.valueOf(c));
        HashMap map = null;
        if (fontSpecific)
            map = cmap10;
        else
            map = cmap31;
        if (map == null)
            return null;
        if (fontSpecific) {
            if ((c & 0xffffff00) == 0 || (c & 0xffffff00) == 0xf000)
                return (int[])map.get(Integer.valueOf(c & 0xff));
            else
                return null;
        }
        else
            return (int[])map.get(Integer.valueOf(c));
    }
745773
public static String getBrief(String str, int len, char c) {
		if (str == null)
			return "";
		if (str.length() < len)
			return str;
		return new StringBuffer(str.substring(0, len - 3)).append(c).append(c)
				.append(c).toString();
	}
228370
public static boolean isLetterNumber(char c) {
		return (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || (c >= 'A' && c <= 'Z') || c == '_' || c == '.'
				|| c == '@' || c == '#' || c == '$' || c == '+' || c == '-';
	}
1026795
private String getTypeString(Class<?> c)
   {
      String result = TYPE_MAP.get(c);
      if (result == null)
      {
         result = c.getName();
         if (!result.endsWith(";") && !result.startsWith("["))
         {
            result = "L" + result + ";";
         }
      }
      return result;
   }
434419
private static String classToString(final Class<?> c) {
        if (c.isArray()) {
            return toString(c.getComponentType()) + "[]";
        }

        final StringBuilder buf = new StringBuilder();

        if (c.getEnclosingClass() != null) {
            buf.append(classToString(c.getEnclosingClass())).append('.').append(c.getSimpleName());
        } else {
            buf.append(c.getName());
        }
        if (c.getTypeParameters().length > 0) {
            buf.append('<');
            appendAllTo(buf, ", ", c.getTypeParameters());
            buf.append('>');
        }
        return buf.toString();
    }
1007754
public static String wrapCharArray(char[] c)
    {
        if (c == null)
            return null;

        String s = null;

        if (stringConstructor != null)
        {
            try
            {
                s = stringConstructor.newInstance(0, c.length, c);
            } 
            catch (InvocationTargetException ite) {
                // The underlying constructor failed. Unwrapping the exception.
                Throwable cause = ite.getCause();
                logger.error("Underlying string constructor threw an error: {}",
                    cause == null ? ite.getMessage() : cause.getMessage());
            }
            catch (Exception e)
            {
                JVMStabilityInspector.inspectThrowable(e);
                // Swallowing as we'll just use a copying constructor
            }
        }
        return s == null ? new String(c) : s;
    }
904070
public static Type getType(final Class c) {
        if (c.isPrimitive()) {
            if (c == Integer.TYPE) {
                return INT_TYPE;
            } else if (c == Void.TYPE) {
                return VOID_TYPE;
            } else if (c == Boolean.TYPE) {
                return BOOLEAN_TYPE;
            } else if (c == Byte.TYPE) {
                return BYTE_TYPE;
            } else if (c == Character.TYPE) {
                return CHAR_TYPE;
            } else if (c == Short.TYPE) {
                return SHORT_TYPE;
            } else if (c == Double.TYPE) {
                return DOUBLE_TYPE;
            } else if (c == Float.TYPE) {
                return FLOAT_TYPE;
            } else /* if (c == Long.TYPE) */{
                return LONG_TYPE;
            }
        } else {
            return getType(getDescriptor(c));
        }
    }
459363
public static String padleft(String s, int len, char c) {
        s = s.trim();
        if (s.length() > len) {
            return s;
        }
        final StringBuilder sb = new StringBuilder(len);
        int fill = len - s.length();
        while (fill-- > 0) {
            sb.append(c);
        }
        sb.append(s);
        return sb.toString();
    }
557049
private static String escape(char c) {
		switch (c) {
		case '\b':
			return "\\b";
		case '\t':
			return "\\t";
		case '\n':
			return "\\n";
		case '\f':
			return "\\f";
		case '\r':
			return "\\r";
		default:
			if (c < StrUtil.C_SPACE || //
					(c >= '\u0080' && c <= '\u00a0') || //
					(c >= '\u2000' && c <= '\u2010') || //
					(c >= '\u2028' && c <= '\u202F') || //
					(c >= '\u2066' && c <= '\u206F')//
			) {
				return HexUtil.toUnicodeHex(c);
			} else {
				return Character.toString(c);
			}
		}
	}
250399
public static String getClassPath(Class<?> c) {
		String strClassFullName = c.getName();
		String strClassName = strClassFullName.substring(strClassFullName
				.lastIndexOf(".") + 1);
		String strClassPathName = getClassPathName(c);

		ClassLoader cl = c.getClassLoader();
		if (cl == null) {
			cl = ClassLoader.getSystemClassLoader();
			return null;
		}

		URL urlClass = cl.getResource(strClassPathName);
		if (urlClass == null)
			return null;

		String strUrl = urlClass.toString();
		return strUrl.substring(0, strUrl.lastIndexOf(strClassName));
	}
1003532
protected int charGroup(char c) {
    int         result;

    result = 0;

    if ( (c >= 'a') && (c <= 'z') )
      result = 2;
    else if ( (c >= '0') && (c <= '9') )
      result = 1;

    return result;
  }
1122456
private String getSymbolName(char c)
   {
      String result = null;

      switch (c)
      {
         case ',':
         {
            result = "Comma";
            break;
         }

         case '.':
         {
            result = "Period";
            break;
         }
      }

      return result;
   }
752772
protected KeyBucket getBucket(char c) {
        if (c > this.buckets.length) {
            // can't handle non-ASCII chars
            return null;
        }
        int index = c;
        // if we're case-insensitive, push uppercase into lowercase buckets
        if (!isCaseSensitive() && (c >= 'A' && c <= 'Z')) {
            index += 32;
        }
        return this.buckets[index];
    }
1098461
public int[] getMetricsTT(int c) {
        if (cmapExt != null) {
            return (int[])cmapExt.get(Integer.valueOf(c));
        }
        if (!fontSpecific && cmap31 != null) { 
            return (int[])cmap31.get(Integer.valueOf(c));
        }
        if (fontSpecific && cmap10 != null) { 
            return (int[])cmap10.get(Integer.valueOf(c));
        }
        if (cmap31 != null) { 
            return (int[])cmap31.get(Integer.valueOf(c));
        }
        if (cmap10 != null) {
            return (int[])cmap10.get(Integer.valueOf(c));
        }
        return null;
    }