Merge pull request #1536 from petersmythe/fix/improve-dispatcher-logging

Improve dispatcher error logging for client errors

Author: petersmythe

geowebcache/core/src/main/java/org/geowebcache/GeoWebCacheDispatcher.java

@@ -316,6 +316,9 @@ public ServletOutputStream getOutputStream() throws IOException {
                     CacheResult.OTHER,
                     runtimeStats);
             LOG.warning(e.getMessage());
+        } catch (IllegalArgumentException e) {
+            ResponseUtils.writeErrorPage(response, 400, e.getMessage(), runtimeStats);
+            LOG.log(Level.WARNING, e.getMessage());
         } catch (Exception e) {
             if (!(e instanceof BadTileException) || LOG.isLoggable(Level.FINE)) {
                 LOG.severe(e.getMessage() + " " + request.getRequestURL().toString());