gzipresponsewrapper.java

Jodd是一个开源的公用Java基础类库

package jodd.servlet.filters;

import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;

/**
 * Implementation of <b>HttpServletResponseWrapper</b> that works with
 * the CompressionServletResponseStream implementation..
 */

public class GzipResponseWrapper extends HttpServletResponseWrapper {

	/**
	 * Calls the parent constructor which creates a ServletResponse adaptor
	 * wrapping the given response object.
	 *
	 * @param response
	 */
	public GzipResponseWrapper(HttpServletResponse response) {
		super(response);
		origResponse = response;
	}



	/**
	 * Original response
	 */
	protected HttpServletResponse origResponse = null;

	/**
	 * The ServletOutputStream that has been returned by
	 * <code>getOutputStream()</code>, if any.
	 */
	protected ServletOutputStream stream = null;

	/**
	 * The PrintWriter that has been returned by <code>getWriter()</code>, if
	 * any.
	 */
	protected PrintWriter writer = null;

	/**
	 * The threshold number to compress
	 */
	protected int threshold = 0;

	/**
	 * Content type
	 */
	protected String contentType = null;

	// ---------------------------------------------------------------- public
	
	
	/**
	 * Set content type
	 *
	 * @param contentType
	 */
	public void setContentType(String contentType) {
		this.contentType = contentType;
		origResponse.setContentType(contentType);
	}

	/**
	 * Set threshold number
	 *
	 * @param threshold
	 */
	public void setCompressionThreshold(int threshold) {
		this.threshold = threshold;
	}

	/**
	 * Creates and returns a ServletOutputStream to write the content associated
	 * with this Response.
	 *
	 * @return a ServletOutputStream to write the content associated with response
	 * @exception IOException
	 *                   if an input/output error occurs
	 */
	public ServletOutputStream createOutputStream() throws IOException {
		GzipResponseStream stream = new GzipResponseStream(origResponse);
		stream.setBuffer(threshold);
		return stream;
	}


	/**
	 * Finishes a response.
	 */
	public void finishResponse() {
		try {
			if (writer != null) {
				writer.close();
			} else {
				if (stream != null)
					stream.close();
			}
		} catch (IOException e) {
		}
	}

	// ---------------------------------------------------------------- ServletResponse


	/**
	 * Flush the buffer and commit this response.
	 *
	 * @exception IOException
	 *                   if an input/output error occurs
	 */
	public void flushBuffer() throws IOException {
		if (stream != null) {
			((GzipResponseStream)stream).flush();
		}
	}

	/**
	 * Returns the servlet output stream associated with this Response.
	 *
	 * @return servlet output stream associated with this Response
	 * @exception IllegalStateException
	 *                   if <code>getWriter</code> has
	 *                   already been called for this response
	 * @exception IOException
	 *                   if an input/output error occurs
	 */
	public ServletOutputStream getOutputStream() throws IOException {

		if (writer != null) {
			throw new IllegalStateException("getWriter() has already been called for this response");
		}
		if (stream == null) {
			stream = createOutputStream();
		}
		return(stream);

	}

	/**
	 * Returns the writer associated with this Response.
	 *
	 * @return the writer associated with this Response
	 * @exception IllegalStateException
	 *                   if <code>getOutputStream</code> has
	 *                   already been called for this response
	 * @exception IOException
	 *                   if an input/output error occurs
	 */
	public PrintWriter getWriter() throws IOException {

		if (writer != null) {
			return writer;
		}

		if (stream != null) {
			throw new IllegalStateException("getOutputStream() has already been called for this response");
		}

		stream = createOutputStream();
		
		String charEnc = origResponse.getCharacterEncoding();
		if (charEnc != null) {
			writer = new PrintWriter(new OutputStreamWriter(stream, charEnc));
		} else {
			writer = new PrintWriter(stream);
		}
		return(writer);
	}


	public void setContentLength(int length) {
	}

}