FileView.java

/*
 Copyright 2006 - 2009 Under Dusken

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
package org.pegadi.webapp.view;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.servlet.view.AbstractView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.Map;

public class FileView extends AbstractView {

    private final Logger log = LoggerFactory.getLogger(getClass());

    protected void renderMergedOutputModel(Map map, HttpServletRequest request,
                                           HttpServletResponse response) throws IOException {
        // get the file from the map
        File file = (File) map.get("file");

        // check if it exists
        if (file == null || !file.exists() || !file.canRead()) {
            log.warn("Error reading: " + file);
            try {
                response.sendError(404);
            } catch (IOException e) {
                log.error("Could not write to response", e);
            }
            return;
        }
        // give some info in the response
        response.setContentType(getServletContext().getMimeType(
                file.getAbsolutePath()));
        // files does not change so often, allow three days caching
        response.setHeader("Cache-Control", "max-age=259200");
        response.setContentLength((int) file.length());

        // start writing to the response
        BufferedOutputStream out = null;
        BufferedInputStream in = null;
        try {
            out = new BufferedOutputStream(response.getOutputStream());
            in = new BufferedInputStream(new FileInputStream(file));
            int c = in.read();
            while (c != -1) {
                out.write(c);
                c = in.read();
            }
        } finally {
            if (in != null) {
                in.close();
            }
            if (out != null) {
                out.flush();
                out.close();
            }
        }
    }
}