stringutils.java

这是一个轻便的j2ee的web应用框架,是一个在多个项目中运用的实际框架,采用struts,hebinate,xml等技术,有丰富的tag,role,navigation,session,dictio

package com.esimple.framework.util;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;

public abstract class StringUtils {

	/**
	 * Count the occurrences of the substring in string s
	 * @param s string to search in. Returns 0 if this is null
	 * @param sub string to search for. Return 0 if this is null.
	 */
	public static int countOccurrencesOf(String s, String sub) {
		if (s == null || sub == null || "".equals(sub))
			return 0;
		int count = 0, pos = 0, idx = 0;
		while ((idx = s.indexOf(sub, pos)) != -1) {
			++count;
			pos = idx + sub.length();
		}
		return count;
	}

	/**
	 * Replaces all occurences of a substring within a string with another string.
	 * @param inString String to examine
	 * @param oldPattern String to replace
	 * @param newPattern String to insert
	 * @return a String with the replacements
	 */
	public static String replace(String inString, String oldPattern, String newPattern) {
		// Pick up error conditions
		if (inString == null)
			return null;
		if (oldPattern == null || newPattern == null)
			return inString;

		StringBuffer sbuf = new StringBuffer();      // Output StringBuffer we'll build up
		int pos = 0;                        // Our position in the old string
		int index = inString.indexOf(oldPattern); // The index of an occurrence we've found, or -1
		int patLen = oldPattern.length();
		while (index >= 0) {
			sbuf.append(inString.substring(pos, index));
			sbuf.append(newPattern);
			pos = index + patLen;
			index = inString.indexOf(oldPattern, pos);
		}
		sbuf.append(inString.substring(pos));     // Remember to append any characters to the right of a match
		return sbuf.toString();
	}

	/**
	 * Delete all occurrences of the given substring.
	 * @param pattern pattern to delete all occurrences of
	 */
	public static String delete(String inString, String pattern) {
		return replace(inString, pattern, "");
	}

	/**
	 * Delete any character in a given string.
	 * @param chars characters to delete e.g. az\n will delete as, zs and new lines
	 */
	public static String deleteAny(String inString, String chars) {
		if (inString == null || chars == null)
			return inString;
		StringBuffer out = new StringBuffer();
		for (int i = 0; i < inString.length(); i++) {
			char c = inString.charAt(i);
			if (chars.indexOf(c) == -1) {
				out.append(c);
			}
		}
		return out.toString();
	}

	/**
	 * Tokenize the given String into a String array via a StringTokenizer.
	 * @param s the String to tokenize
	 * @param delimiters the delimiter characters, assembled as String
	 * @param trimTokens trim the tokens via String.trim
	 * @param ignoreEmptyTokens omit empty tokens from the result array
	 * @return an array of the tokens
	 * @see java.util.StringTokenizer
	 * @see java.lang.String#trim
	 */
	public static String[] split(String s, String delimiters,
	                                             boolean trimTokens, boolean ignoreEmptyTokens) {
		StringTokenizer st = new StringTokenizer(s, delimiters);
		List tokens = new ArrayList();
		while (st.hasMoreTokens()) {
			String token = st.nextToken();
			if (trimTokens) {
				token = token.trim();
			}
			if (!(ignoreEmptyTokens && token.length() == 0)) {
				tokens.add(token);
			}
		}
		return (String[]) tokens.toArray(new String[tokens.size()]);
	}

	/**
	 * Take a String which is a delimited list and convert it to a String array
	 * @param s String
	 * @param delimiter delimiter. This will not be returned
	 * @return an array of the tokens in the list
	 */
	public static String[] delimitedListToStringArray(String s, String delimiter) {
		if (s == null)
			return new String[0];
		if (delimiter == null)
			return new String[]{s};

		List l = new LinkedList();
		int pos = 0;
		int delpos = 0;
		while ((delpos = s.indexOf(delimiter, pos)) != -1) {
			l.add(s.substring(pos, delpos));
			pos = delpos + delimiter.length();
		}
		if (pos <= s.length()) {
			// add rest of String
			l.add(s.substring(pos));
		}

		return (String[]) l.toArray(new String[l.size()]);
	}

	/**
	 * Convert a CSV list into an array of Strings.
	 * @param s CSV list
	 * @return an array of Strings. Returns the empty array if
	 * s is null.
	 */
	public static String[] commaDelimitedListToStringArray(String s) {
		return delimitedListToStringArray(s, ",");
	}

	/**
	 * Convenience method to convert a CSV string list to a set.
	 * Note that this will suppress duplicates.
	 * @param s CSV String
	 * @return a Set of String entries in the list
	 */
	public static Set commaDelimitedListToSet(String s) {
		Set set = new TreeSet();
		String[] tokens = commaDelimitedListToStringArray(s);
		for (int i = 0; i < tokens.length; i++)
			set.add(tokens[i]);
		return set;
	}

	/**
	 * Convenience method to return a String array as a delimited (e.g. CSV)
	 * String. Useful for toString() implementations
	 * @param arr array to display. Elements may be of any type (toString() will be
	 * called on each element).
	 * @param delim delimiter to use (probably a ,)
	 */
	public static String arrayToDelimitedString(Object[] arr, String delim) {
		if (arr == null)
			return "null";
		else {
			StringBuffer sb = new StringBuffer();
			for (int i = 0; i < arr.length; i++) {
				if (i > 0)
					sb.append(delim);
				sb.append(arr[i]);
			}
			return sb.toString();
		}
	}

	/**
	 * Convenience method to return a Collection as a delimited (e.g. CSV)
	 * String. Useful for toString() implementations.
	 * @param c Collection to display
	 * @param delim delimiter to use (probably a ",")
	 */
	public static String collectionToDelimitedString(Collection c, String delim) {
		if (c == null)
			return "null";
		StringBuffer sb = new StringBuffer();
		Iterator itr = c.iterator();
		int i = 0;
		while (itr.hasNext()) {
			if (i++ > 0)
				sb.append(delim);
			sb.append(itr.next());
		}
		return sb.toString();
	}

	/**
	 * Convenience method to return a String array as a CSV String.
	 * Useful for toString() implementations.
	 * @param arr array to display. Elements may be of any type (toString() will be
	 * called on each element).
	 */
	public static String arrayToCommaDelimitedString(Object[] arr) {
		return arrayToDelimitedString(arr, ",");
	}

	/**
	 * Convenience method to return a Collection as a CSV String.
	 * Useful for toString() implementations.
	 * @param c Collection to display
	 */
	public static String collectionToCommaDelimitedString(Collection c) {
		return collectionToDelimitedString(c, ",");
	}

	public static String[] addStringToArray(String[] arr, String s) {
		String[] newArr = new String[arr.length + 1];
		System.arraycopy(arr, 0, newArr, 0, arr.length);
		newArr[arr.length] = s;
		return newArr;
	}
	/** Removes all spaces from a string */
	public static String removeSpaces(String str) {
		StringBuffer newString = new StringBuffer();
		for (int i = 0; i < str.length(); i++) {
			if (str.charAt(i) != ' ')
				newString.append(str.charAt(i));
		}
		return newString.toString();        
	}
	/**
	 * 本地字符集转换成unicode。
	 * @return java.lang.String
	 */
	public static String native2unicode(String s) {
		if(s==null || s.length()==0) {
			return null;
		}
		byte [] buffer = new byte[s.length()];

		for(int i=0;i<s.length();i++) {
			buffer[i] = (byte)s.charAt(i);
		}

		return new String(buffer);
	}

	/**
	 * unicode转为本地字符集
	 * @ param String Unicode编码的字符串
	 * @ return String
	 */
	public static String unicode2native(String s) {
		if(s==null || s.length()==0) {
			return null;
		}
		char [] buffer = new char[s.length() * 2];
		char c;
		int j=0;
		for(int i=0;i<s.length();i++) {
			if(s.charAt(i)>=0x100){
				c = s.charAt(i);
				byte [] buf = (""+c).getBytes();
				buffer[j++] = (char)buf[0];
				buffer[j++] = (char)buf[1];
			} else {
				buffer[j++] = s.charAt(i);
			}
		}
		return new String(buffer,0,j);
	}	
}