replacetextstream.java

tomcat与java web 这本书的配套源代码

import java.io.*;
import javax.servlet.*;


class ReplaceTextStream extends ServletOutputStream {
     private OutputStream intStream;
     private ByteArrayOutputStream baStream;
     private boolean closed = false;

     private String oldStr;
     private String newStr;

     public ReplaceTextStream(OutputStream outStream,
                              String searchStr,
                              String replaceStr) {
          intStream = outStream;
          baStream = new ByteArrayOutputStream();
          oldStr = searchStr;
          newStr = replaceStr;
     }

    public void write(int a)throws IOException{
       baStream.write(a);
    }

   public void println(String s)throws IOException{
     s=s+"\n";
     byte[] bs=s.getBytes();
     baStream.write(bs);
   }

   public void close() throws java.io.IOException {
          if (!closed) {

            processStream();
            intStream.close();
            closed = true;
          }
       }

    public void flush() throws java.io.IOException {
        if (baStream.size() != 0) {
             if (! closed) {
              processStream();           // need to synchronize the flush!
              baStream = new ByteArrayOutputStream();
              }
           }
        }

     public void processStream() throws java.io.IOException {
         intStream.write(replaceContent(baStream.toByteArray()));
         intStream.flush();
     }



     public byte []  replaceContent(byte [] inBytes) {

          String retVal ="";
          String firstPart="";

          String tpString = new String(inBytes);
          String srchString = (new String(inBytes)).toLowerCase();

          int endBody = srchString.indexOf(oldStr);

          if (endBody != -1) {
               firstPart = tpString.substring(0, endBody);
           retVal = firstPart + newStr +
                  tpString.substring(endBody + oldStr.length());

            } else {
              retVal=tpString;
            }

          return retVal.getBytes();

    }
}