filtertag.java

servlet与jsp核心编程 书籍源码 部分

package coreservlets.tags;

import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import java.io.*;
import coreservlets.*;

/** A tag that replaces <, >, ", and & with their HTML
 *  character entities (&lt;, &gt;, &quot;, and &amp;).
 *  After filtering, arbitrary strings can be placed
 *  in either the page body or in HTML attributes.
 *  <P>
 *  Taken from Core Servlets and JavaServer Pages
 *  from Prentice Hall and Sun Microsystems Press,
 *  http://www.coreservlets.com/.
 *  &copy; 2000 Marty Hall; may be freely used or adapted.
 */

public class FilterTag extends BodyTagSupport {
  public int doAfterBody() {
    BodyContent body = getBodyContent();
    String filteredBody =
      ServletUtilities.filter(body.getString());
    try {
      JspWriter out = body.getEnclosingWriter();
      out.print(filteredBody);
    } catch(IOException ioe) {
      System.out.println("Error in FilterTag: " + ioe);
    }
    // SKIP_BODY means I'm done. If I wanted to evaluate
    // and handle the body again, I'd return EVAL_BODY_TAG.
    return(SKIP_BODY);
  }
}