exportfilter.java

exTreme taglib的使用

/*
 * Copyright 2004 original author or authors.
 *
 * 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.extremecomponents.table.filter;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

import org.apache.avalon.framework.logger.ConsoleLogger;
import org.apache.avalon.framework.logger.Logger;
import org.apache.commons.lang.StringUtils;
import org.apache.fop.apps.Driver;
import org.apache.fop.messaging.MessageHandler;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.extremecomponents.table.handler.ExportHandler;
import org.extremecomponents.util.MimeUtils;
import org.xml.sax.InputSource;

/**
 * Filter to handle the incoming FOP requests to generate the PDF document.
 * 
 * 
 * <filter><filter-name>ExportFilter </filter-name> <display-name>ExportFilter
 * </display-name> <filter-class>org.extremecomponents.table.filter.ExportFilter
 * </filter-class> </filter> <filter-mapping><filter-name>ExportFilter
 * </filter-name> <url-pattern>* </url-pattern> </filter-mapping>
 * 
 * <!-- Action Servlet Configuration --> <filter-mapping>
 * <filter-name>ExportFilter </filter-name> <servlet-name>eXtremeTest
 * </servlet-name> </filter-mapping>
 * 
 * @author jeff johnston
 */
public class ExportFilter implements Filter {
    private Logger log = null;

    public void init(FilterConfig filterConfig)
            throws ServletException {
    }

    public void destroy() {
    }

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        String invokeExport = null;
        String exportName = null;

        if (ExportFilterUtils.isExportMode(request)) {
            invokeExport = ExportFilterUtils.findInvokeExport(request);
            exportName = ExportFilterUtils.findExportName(request);
            GenericResponseWrapper wrapper = new GenericResponseWrapper((HttpServletResponse) response);
            chain.doFilter(request, wrapper);
        } else {
            chain.doFilter(request, response);
        }

        if (StringUtils.isNotBlank(invokeExport)) {
            setResponseHeaders((HttpServletResponse) response, exportName);
            try {
                if (exportName.endsWith(ExportHandler.PDF))
                    handlePDF(request, response);
                else if (exportName.endsWith(ExportHandler.XLS))
                    handleXLS(request, response);
                else if (exportName.endsWith(ExportHandler.TXT) || exportName.endsWith(ExportHandler.CSV))
                    handleTXT(request, response);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    protected void handleXLS(ServletRequest request, ServletResponse response)
            throws Exception {
        HSSFWorkbook wb = (HSSFWorkbook) request.getAttribute(ExportHandler.EXPORT_DATA);
        if ( wb != null ) {
            wb.write(response.getOutputStream());
            response.getOutputStream().flush();
            response.getOutputStream().close();
        }
    }

    protected void handlePDF(ServletRequest request, ServletResponse response)
            throws Exception {
        String output = (String) request.getAttribute(ExportHandler.EXPORT_DATA);
        if ( output != null ) {
            InputStream is = new ByteArrayInputStream(output.getBytes("UTF-8"));
            renderFO(new InputSource(is), (HttpServletResponse) response);
        }
    }

    protected void handleTXT(ServletRequest request, ServletResponse response)
            throws Exception {
        String output = (String) request.getAttribute(ExportHandler.EXPORT_DATA);
        if ( output != null ) {
            byte[] content = output.getBytes();
            response.setContentLength(content.length);
            response.getOutputStream().write(content);
            response.getOutputStream().flush();
            response.getOutputStream().close();
        }
    }

    protected void renderFO(InputSource foFile, HttpServletResponse response)
            throws Exception {
        ByteArrayOutputStream out = new ByteArrayOutputStream();

        Driver driver = new Driver(foFile, out);

        if (log == null) {
            log = new ConsoleLogger(ConsoleLogger.LEVEL_WARN);
            MessageHandler.setScreenLogger(log);
        }

        driver.setLogger(log);
        driver.setRenderer(Driver.RENDER_PDF);
        driver.run();

        byte[] content = out.toByteArray();
        response.setContentLength(content.length);
        response.getOutputStream().write(content);
        response.getOutputStream().flush();
        response.getOutputStream().close();
    }

    protected void setResponseHeaders(HttpServletResponse response, String exportName) {
        String mimeType = MimeUtils.getFileMimeType(exportName);
        if (StringUtils.isNotBlank(mimeType)) {
            response.setContentType(mimeType);
        }

        response.setHeader("Content-Disposition", "attachment;filename=\"" + exportName + "\"");
        response.setHeader("Pragma", "public");
        response.setDateHeader("Expires", (System.currentTimeMillis() + 1000));
    }
}