java字符串替换字符串实例,对replace方法的重写

package com.citycollege.stw;

public class testreplace {

public static final String replace( String line, String oldString, String newString )
{
if (line == null)
{
return null;
}
int i=0;
if ( ( i=line.indexOf( oldString, i ) ) >= 0 )
{
char [] line2 = line.toCharArray(); //字符串放入数组
char [] newString2 = newString.toCharArray(); //要替换的字符串
int oLength = oldString.length(); //被替换的字符串的长度
StringBuffer buf = new StringBuffer(line2.length);
buf.append(line2, 0, i).append(newString2);
i += oLength;
int j = i;
while( ( i=line.indexOf( oldString, i ) ) > 0 )
{
buf.append(line2, j, i-j).append(newString2);
i += oLength;
j = i;
}
buf.append(line2, j, line2.length - j);
return buf.toString();
}
return line;
}

public static void main(String args[]){
String s="I OK OK best OK" +
"She OK OK BESTU OK";
String s1=replace(s,"OK","hello");
System.out.println(s1);

String s2="I OK OK best OK";
String temp="hello";
String s3=s2.replace("0K", temp);

System.out.println(s3);

}

}