stringutils.java

数据库备份程序示例

import java.util.*;

public class StringUtils extends Object
{
	public static String stringValueFromVector(Vector anArray,char aChar)
	{
		StringBuffer buff = new StringBuffer();
		
		if(anArray != null)
		{
			buff.append(anArray.elementAt(0));
		
			if(buff.length() > 0)
			{
				int i,max;
			
				max = anArray.size();
			
				for(i=1;i<max;i++)
				{
					if(aChar != '\0') buff.append(aChar);
					buff.append(anArray.elementAt(i));
				}
			}
		}
		
		return buff.toString();
	}
	
	public static String join(String[] strings, String delimiter)
	{
		StringBuffer sb = new StringBuffer();
		int stringCount=0;
		int i;
		
		if(strings != null) stringCount = strings.length;

		if(delimiter == null)
		{
			delimiter = " ";
		}

		for(i=0; i < stringCount; i++)
		{
			sb.append(strings[i]);
			if(i+1 < stringCount)
			{
				sb.append(delimiter);
			}
		}
		
		return sb.toString();
	}

	/**
	 * Joins an array of strings into a single string separated by a space
	 *
	 * @param     strings an array of strings to join
	 * @return    The joined strings.
	 */
	public static String join(String[] strings)
	{
		return StringUtils.join(strings, " ");
	}
	
	public static Vector vectorFromString(String str, String delimiter)
	{
		Vector dynaArr = new Vector();
		int curdex = 0;
		int lastdex = 0;
		int dellength = 0;
		int strlen = 0;

		if(str != null) strlen = str.length();
		
		if(delimiter == null)
		{
			delimiter = " ";
		}
		
		dellength = delimiter.length();

		if(strlen == 0)
		{
			return null;
		}
		try
		{
			while(lastdex != -1)
			{
				lastdex = str.indexOf(delimiter, curdex);
				if(lastdex == -1)
				{
					dynaArr.addElement(str.substring(curdex, strlen));
				}
				else
				{
					dynaArr.addElement(str.substring(curdex, lastdex));
				}
				curdex = lastdex + dellength;
			}
		}
		catch (StringIndexOutOfBoundsException ex)
		{
			dynaArr.addElement(str.substring(curdex, strlen));
		}
		
		return dynaArr;
	}

	public static String[] split(String str)
	{
		return StringUtils.split(str, " ");
	}

	public static String[] split(String str, String delimiter)
	{
		Vector dynaArr;
		String[] strings;
		int i,max = 0;
		
		dynaArr = vectorFromString(str,delimiter);

		max = dynaArr.size();
		
		strings = new String[max];

		for(i=0; i<max; i++)
		{
			strings[i] = (String)dynaArr.elementAt(i);
		}
		
		return strings;
	}
	
	public static Vector splitLines(String str)
	{
		Vector retVal = new Vector();
		char c;
		int i,max;
		StringBuffer curLine = new StringBuffer();
		
		if(str == null) return retVal;
		
		max = str.length();
		
		for(i=0;i<max;i++)
		{
			c = str.charAt(i);
			
			if((c=='\n')||(c=='\r'))
			{
				if(curLine.length()>0)
					retVal.addElement(curLine.toString());
					
				curLine.setLength(0);
			}
			else
			{
				curLine.append(c);
			}
		}
		
		if(curLine.length()>0)
			retVal.addElement(curLine.toString());
		
		return retVal;
	}
	
	private static void printElements(String[] strings)
	{
		for(int i = 0; i<strings.length; i++)
		{
			System.out.println(strings[i]);
		}
	}
	
	public static String removeTags(String s)
	{
		StringBuffer buffer = new StringBuffer();
		String retVal = s;
		int i,max;
		boolean inTag;
		char c;
		
		if(s == null) return s;
		
		if(s.indexOf("<") >= 0)
		{
			inTag = false;
			
			max = s.length();
			
			for(i=0;i<max;i++)
			{
				c = s.charAt(i);
				
				if(c == '<') inTag = true;
				else if(c == '>') inTag = false;
				else if(!inTag)
				{
					if(c == '\n') buffer.append(' ');
					else if(c == '\t') buffer.append(' ');
					else if(c != '\r') buffer.append(c);
				}
			}
			
			retVal = buffer.toString();
		}
		
		return retVal;
	}
	
	final static String octalDigits = "01234567";
	final static String hexDigits = "0123456789abcdefABCDEF";
	final static String escChars = "\n\t\b\r\f\\\'\"";
	final static String unescChars = "ntbrf\\'\"";

	public static String unescape(String cstring)
	{
		if(cstring==null) return cstring;
		
	    int len = cstring.length();
	    StringBuffer sb = new StringBuffer(len);
	    int val;
	    int unesc;

	    for(int i=0; i<len; i++)
	    {
	      char ch = cstring.charAt(i);

	      if(ch=='\\')
	      {
	            i++;
	            ch = cstring.charAt(i);

	            if(ch>='0' && ch<='7')
	            {
	              val=0;
	              
	              for (int j=i; j-i<3 && octalDigits.indexOf(ch=cstring.charAt(j))!=-1; j++)
	              {
	                    val = val*8 + (((int)ch)-'0');
	              }
	              
	              ch = (char)val;
	              i+=3-1;
	            }
	            else if(ch=='u')
	            {
	              i++;
	              val=0;
	              
	              for(int j=i; j-i<4; j++)
	              {
	                    ch=cstring.charAt(j);
	                    
	                    if (hexDigits.indexOf(ch)==-1)
	                    {
	                    	return null;
	                    }
	                    
	                    val *= 16;
	                    
	                    if (Character.isDigit(ch)) val += (((int)ch)-'0');
	                    else if (Character.isLowerCase(ch)) val += (((int)ch)-'a');
	                    else val += (((int)ch)-'A');
	              }
	              
	              i+=4-1;
	              ch = (char)val;
	            }
	            else if((unesc=unescChars.indexOf(ch))!=-1)
	            {
	              ch = escChars.charAt(unesc);
	            }
	            else
	            {
	                //leave it
	            }
	      }

	      sb.append(ch);        // usually have some translated character to append now
	    }

	    return sb.toString();
	}

	public static String escape(String raw)
	{
		if(raw==null) return raw;
		
		int max = raw.length();
	    StringBuffer sb = new StringBuffer(max*2);
	    int unesc;
		int len;
		String hex;

	    for (int i=0; i<max; i++)
	    {
			char ch = raw.charAt(i);
			int ich = (int)ch;

			if ((unesc=escChars.indexOf(ch))!=-1)
			{
			    sb.append('\\');
			    sb.append(unescChars.charAt(unesc));
			}
			else if(ch<' ' || ich>=0x7f /*|| ich>0xff*/)
			{     // not printable or Unicode
			    sb.append("\\u");
			    
			    hex =  Integer.toHexString(ich);
			    len = hex.length();
			    
			    for(int j=len;j<4;j++) sb.append('0');
			    
			    sb.append(hex);
			}
			else
			{
			    sb.append(ch);
			}
	    }       

	    return sb.toString();
	}
	
	public static String htmlEncode(String val)
	{
		StringBuffer	buf = new StringBuffer(val.length() + 8);
		char			c;

		for(int i = 0; i < val.length(); i++)
		{
			c = val.charAt(i);
			
			switch(c)
			{
				case '<':
					buf.append("&lt;");
					break;
				case '>':
					buf.append("&gt;");
					break;
				case '&':
					buf.append("&amp;");
					break;
				case '\"':
					buf.append("&quot;");
					break;
				default:
					buf.append(c);
					break;
			}
		}
		
		return buf.toString();
	}

	public static void main(String[] args)
	{
		String[] strings;

		strings = StringUtils.split("This is a test to see what is going on ");
		printElements(strings);

		System.out.println(StringUtils.join(strings));

		strings = StringUtils.split("This is a test::This is another:: space", "::");
		printElements(strings);

		System.out.println(StringUtils.join(strings, "::"));
		
		System.out.println(StringUtils.escape("\n\t\b\r\'\""));
	}
}