return writer;
else {
outputType = OUTPUT_WRITER;
writer = new PrintWriter(new OutputStreamWriter(buffer,
getCharacterEncoding()));
return writer;
}
}
public ServletOutputStream getOutputStream() throws IOException {
if (outputType == OUTPUT_WRITER)
throw new IllegalStateException();
else if (outputType == OUTPUT_STREAM)
return output;
else {
outputType = OUTPUT_STREAM;
output = new WrappedOutputStream(buffer);
return output;
}
}
public void flushBuffer() throws IOException {
if (outputType == OUTPUT_WRITER)
writer.flush();
if (outputType == OUTPUT_STREAM)
output.flush();
}
public void reset() {
outputType = OUTPUT_NONE;
buffer.reset();
}
/**
* Call this method to get cached response data.
*
* @return byte array buffer.
* @throws IOException
*/
public byte[] getResponseData() throws IOException {
flushBuffer();
return buffer.toByteArray();
}
/**
* This class is used to wrap a ServletOutputStream and store output stream
* in byte[] buffer.
*/
class WrappedOutputStream extends ServletOutputStream {
private ByteArrayOutputStream buffer;
public WrappedOutputStream(ByteArrayOutputStream buffer) {
this.buffer = buffer;
}
public void write(int b) throws IOException {
buffer.write(b);
}
public byte[] toByteArray() {
return buffer.toByteArray();
}
}
}
(2).GZipFilter类
Java代码
public class GZipFilter implements Filter {
public void init(FilterConfig arg0) throws ServletException {
}
public void doFilter(ServletRequest request, ServletResponse
response,
FilterChain chain) throws IOException, ServletException {
HttpServletResponse httpResponse = (HttpServletResponse)
response;
CachedResponseWrapper wrapper = new
CachedResponseWrapper(httpResponse);
// 写入wrapper:
chain.doFilter(request, wrapper);
// 对响应进行处理，这里是进行GZip压缩:
byte[] data = GZipUtil.gzip(wrapper.getResponseData());
httpResponse.setHeader("Content-Encoding", "gzip");
httpResponse.setContentLength(data.length);
ServletOutputStream output = response.getOutputStream();
output.write(data);
output.flush();
}
public void destroy() {
}
}
public class GZipFilter implements Filter {
public void init(FilterConfig arg0) throws ServletException {
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
HttpServletResponse httpResponse = (HttpServletResponse) response;
CachedResponseWrapper wrapper = new CachedResponseWrapper(httpResponse);
// 写入wrapper:
chain.doFilter(request, wrapper);
// 对响应进行处理，这里是进行GZip压缩:
byte[] data = GZipUtil.gzip(wrapper.getResponseData());
httpResponse.setHeader("Content-Encoding", "gzip");
httpResponse.setContentLength(data.length);
ServletOutputStream output = response.getOutputStream();
output.write(data);
output.flush();
}
public void destroy() {
}
}
(3).GZipUtil类
Java代码
public final class GZipUtil {
/** * Do a gzip operation. */
public static byte[