support setting char encoding on output XML

Author: pjfanning

src/main/java/com/fasterxml/jackson/dataformat/xml/XmlFactory.java

@@ -517,6 +517,22 @@ public ToXmlGenerator createGenerator(OutputStream out, JsonEncoding enc) throws
                 _generatorFeatures, _xmlGeneratorFeatures,
                 _objectCodec, _createXmlWriter(ctxt, out), _nameProcessor);
     }
+
+    /**
+     * @param out
+     * @param encoding
+     * @return
+     * @throws IOException
+     * @since 2.16
+     */
+    public ToXmlGenerator createGenerator(OutputStream out, String encoding) throws IOException
+    {
+        // false -> we won't manage the stream unless explicitly directed to
+        final IOContext ctxt = _createContext(_createContentReference(out), false);
+        return new ToXmlGenerator(ctxt,
+                _generatorFeatures, _xmlGeneratorFeatures,
+                _objectCodec, _createXmlWriter(ctxt, out, encoding), _nameProcessor, encoding);
+    }
 
     @Override
     public ToXmlGenerator createGenerator(Writer out) throws IOException
@@ -689,10 +705,15 @@ protected JsonGenerator _createGenerator(Writer out, IOContext ctxt) throws IOEx
      */
 
     protected XMLStreamWriter _createXmlWriter(IOContext ctxt, OutputStream out) throws IOException
+    {
+        return _createXmlWriter(ctxt, out, "UTF-8");
+    }
+
+    protected XMLStreamWriter _createXmlWriter(IOContext ctxt, OutputStream out, String encoding) throws IOException
     {
         XMLStreamWriter sw;
         try {
-            sw = _xmlOutputFactory.createXMLStreamWriter(_decorate(ctxt, out), "UTF-8");
+            sw = _xmlOutputFactory.createXMLStreamWriter(_decorate(ctxt, out), encoding);
         } catch (Exception e) {
             throw new JsonGenerationException(e.getMessage(), e, null);
         }

src/main/java/com/fasterxml/jackson/dataformat/xml/XmlMapper.java

@@ -1,6 +1,7 @@
 package com.fasterxml.jackson.dataformat.xml;
 
 import java.io.IOException;
+import java.io.OutputStream;
 
 import javax.xml.stream.XMLInputFactory;
 import javax.xml.stream.XMLOutputFactory;
@@ -9,6 +10,7 @@
 
 import com.fasterxml.jackson.core.*;
 import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.core.util.ByteArrayBuilder;
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.cfg.CoercionAction;
 import com.fasterxml.jackson.databind.cfg.CoercionInputShape;
@@ -392,4 +394,34 @@ public void writeValue(XMLStreamWriter w0, Object value) throws IOException {
         // NOTE: above call should do flush(); and we should NOT close here.
         // Finally, 'g' has no buffers to release.
     }
+
+    /**
+     * Method that can be used to serialize any Java value as
+     * a byte array.
+
+     * @param value value to write as XML bytes
+     * @param encoding character encoding for the XML output
+     * @return byte array representing the XML output
+     * @throws JsonProcessingException
+     * @since 2.16
+     */
+    public byte[] writeValueAsBytes(Object value, String encoding) throws JsonProcessingException {
+        try (ByteArrayBuilder bb = new ByteArrayBuilder(_jsonFactory._getBufferRecycler())) {
+            _writeValueAndClose(createGenerator(bb, encoding), value);
+            final byte[] result = bb.toByteArray();
+            bb.release();
+            return result;
+        } catch (JsonProcessingException e) { // to support [JACKSON-758]
+            throw e;
+        } catch (IOException e) { // shouldn't really happen, but is declared as possibility so:
+            throw JsonMappingException.fromUnexpectedIOE(e);
+        }
+    }
+
+    private JsonGenerator createGenerator(OutputStream out, String encoding) throws IOException {
+        this._assertNotNull("out", out);
+        JsonGenerator g = ((XmlFactory) _jsonFactory).createGenerator(out, encoding);
+        this._serializationConfig.initialize(g);
+        return g;
+    }
 }

src/main/java/com/fasterxml/jackson/dataformat/xml/ser/ToXmlGenerator.java

@@ -3,6 +3,7 @@
 import java.io.*;
 import java.math.BigDecimal;
 import java.math.BigInteger;
+import java.nio.charset.StandardCharsets;
 import java.util.*;
 
 import javax.xml.XMLConstants;
@@ -213,6 +214,13 @@ private Feature(boolean defaultState) {
      */
     protected XmlNameProcessor.XmlName _nameToEncode = new XmlNameProcessor.XmlName();
 
+    /**
+     * The character encoding for the XML output
+     *
+     * @since 2.16
+     */
+    protected final String _encoding;
+
     /*
     /**********************************************************
     /* Life-cycle
@@ -221,16 +229,24 @@ private Feature(boolean defaultState) {
 
     public ToXmlGenerator(IOContext ctxt, int stdFeatures, int xmlFeatures,
             ObjectCodec codec, XMLStreamWriter sw, XmlNameProcessor nameProcessor)
+    {
+        this(ctxt, stdFeatures, xmlFeatures, codec, sw, nameProcessor, StandardCharsets.UTF_8.name());
+    }
+
+    public ToXmlGenerator(IOContext ctxt, int stdFeatures, int xmlFeatures,
+                          ObjectCodec codec, XMLStreamWriter sw, XmlNameProcessor nameProcessor,
+                          String encoding)
     {
         super(stdFeatures, codec);
         _formatFeatures = xmlFeatures;
         _ioContext = ctxt;
         _originalXmlWriter = sw;
+        _encoding = encoding;
         _xmlWriter = Stax2WriterAdapter.wrapIfNecessary(sw);
         _stax2Emulation = (_xmlWriter != sw);
         _nameProcessor = nameProcessor;
         _xmlPrettyPrinter = (_cfgPrettyPrinter instanceof XmlPrettyPrinter) ?
-        		(XmlPrettyPrinter) _cfgPrettyPrinter : null;
+                (XmlPrettyPrinter) _cfgPrettyPrinter : null;
     }
 
     /**
@@ -245,9 +261,9 @@ public void initGenerator()  throws IOException
         _initialized = true;
         try {
             if (Feature.WRITE_XML_1_1.enabledIn(_formatFeatures)) {
-                _xmlWriter.writeStartDocument("UTF-8", "1.1");
+                _xmlWriter.writeStartDocument(_encoding, "1.1");
             } else if (Feature.WRITE_XML_DECLARATION.enabledIn(_formatFeatures)) {
-                _xmlWriter.writeStartDocument("UTF-8", "1.0");
+                _xmlWriter.writeStartDocument(_encoding, "1.0");
             } else {
                 return;
             }