如何从字符串中删除多个特殊字符，而无需任何内置函数，例如下面的jdk 1.4的replaceAll（）

Question

Using the below function i am able to simply remove a single special character, need multiple types of them to be removed from a single String.

static public String replaceAll(String str, String replace, String replacement )  
{       
StringBuffer sb = new StringBuffer( str );  
int firstOccurrence = sb.toString().indexOf( replace );  

while( firstOccurrence != -1 )   
{     
sb.replace( firstOccurrence, firstOccurrence + replace.length(), replacement );  
         firstOccurrence = sb.toString().indexOf( replace );  
}  

return sb.toString();   
} 

Needs this so it works below jdk 1.4 without all the inbuilt function like replaceAll()

Thanks.

Answer 1

What I would do is remove all special characters, such as control characters, non-ASCII special characters as well as the ASCII ones like this.

public static String stripSpecialCharacters(String str) {
   StringBuffer sb = new StringBuffer();
    for(int i=0;i<str.length();i++) {
        char ch = str.charAt(i);
        if (Character.isLetterOrDigit(ch) || Character.isSpaceChar(ch))
            sb.append(ch);
    }
    return sb.toString();
}

Note: you want to avoid creating multiple characters or re-arranging characters in a StringBuffer as these become O(N^2) operations in this context.

Answer 2

Edit: Your question title says that you want to replace multiple characters, , i have used a simple method to replace multiple special characters in "replace" by a specified character..

EDIT:

static public String replaceAll(String str, String replace, char replacement )  
{    
String T=""; 
int flag=0;  
for(int i=0;i<str.length();i++)
{
      char a=str.charAt(i);
      for(int j=0;j<replace.length();j++)
      {
          if(a==replace.charAt(j))
          flag=1;
      }
      if(flag==1)
      {
          T+=replacement;
          flag=0;
      }
      else
          T+=a;
}
return T;   
}

this should work in all versions.. i have tested this method with jdk that was available around 8 years ago..

Answer 3

This might be what you're looking for, assuming you can use the replaceAll function you provided:

static public String replaceAll(String str, String[] replace, String replacement )  
{        
    String replaced = str;
    for(int i=0; i<replace.length; i++)
    {
        replaced = replaceAll(str, replace[i], replacement);
    } 
    return replaced;
} 

Edit: I may have misunderstood your question, I thought you were looking for a way to replace multiple characters with a single method call, in which case you would pass the array of characters you want to replace as the second parameter in this function.

Answer 4

You can try this too. But I am not sure lower version than jdk 1.4 supports with toCharArray()

 public static String replaceAll(String str, String replace, String replacement )
  {
    char[] strArray =str.toCharArray();
    StringBuffer sb=new StringBuffer();
    for(int i=0;i<strArray.length;i++){
       if(strArray[i]==replace.toCharArray()[0]){
         sb.append(replacement);
       }else {
           sb.append(strArray[i]);
       }
    }
    return sb.toString();
 }