Here's a Java JAX-RS chart exporter

stephen.friedrich · Wed Aug 01, 2012 10:27 pm

If somebody is using JAX-RS, this might be helpful.
Specify the exporting URL on client side:

new Highcharts.Chart({
                exporting: {
                    url: 'chart-export',
                    ...
                },

and include this resource class on the server:

Code: Select all

import org.apache.batik.transcoder.*;
import org.apache.batik.transcoder.image.JPEGTranscoder;
import org.apache.batik.transcoder.image.PNGTranscoder;
import org.apache.fop.svg.PDFTranscoder;

import javax.ws.rs.DefaultValue;
import javax.ws.rs.FormParam;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.core.Response;
import java.io.ByteArrayOutputStream;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;

@Path("chart-export")
public class ChartExportResource {
    public ChartExportResource() {
    }

    @POST
    public Response doExport(@FormParam("filename") @DefaultValue("chart") String fileName,
                             @FormParam("width") @DefaultValue("800") float width,
                             @FormParam("type") @DefaultValue("application/pdf") String type,
                             @FormParam("svg") String svg) throws TranscoderException
    {
        String suffix = "";
        byte[] data;
        String charset = "";
        if ("image/svg+xml".equals(type)) {
            suffix = ".svg";
            data = getUtf8Bytes(svg);
            charset = ";charset=utf-8";
        }
        else {
            Transcoder transcoder;
            if ("application/pdf".equals(type)) {
                transcoder = new PDFTranscoder();
                suffix = ".pdf";
            }
            else if ("image/png".equals(type)) {
                transcoder = new PNGTranscoder();
                suffix = ".png";
            }
            else if ("image/jpeg".equals(type)) {
                transcoder = new JPEGTranscoder();
                suffix = ".jpeg";
            }
            else {
                throw new IllegalArgumentException("Cannot export chart. Unsupported type " + type);
            }
            data = transcode(transcoder, width, svg);
        }

        //noinspection StringToUpperCaseOrToLowerCaseWithoutLocale
        if (!fileName.toLowerCase().endsWith(suffix)) {
            fileName += suffix;
        }

        Response.ResponseBuilder responseBuilder = Response.ok(data, type + charset)
                                                           .header("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
        return responseBuilder.build();
    }

    private byte[] transcode(Transcoder transcoder, float width, String svg) throws TranscoderException {
        transcoder.addTranscodingHint(SVGAbstractTranscoder.KEY_WIDTH, width);
        TranscoderInput input = new TranscoderInput(new StringReader(svg));
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        TranscoderOutput output = new TranscoderOutput(baos);
        transcoder.transcode(input, output);
        byte[] data = baos.toByteArray();
        return data;
    }

    private byte[] getUtf8Bytes(String text) {
        try {
            return text.getBytes("utf-8");
        }
        catch (UnsupportedEncodingException ignore) {
            // Can't happen: UTF-8 is guaranteed to be supported by Java
            return null;
        }
    }
}