Added method U.streamJsonToXml(jsonInputStream, xmlOutputStream, identStep)

src/main/java/com/github/underscore/U.java

@@ -103,6 +103,7 @@ public class U<T> extends Underscore<T> {
             java.util.regex.Pattern.compile(
                     UPPER + "+(?=" + UPPER + LOWER + ")|" + UPPER + "?" + LOWER + "|" + UPPER
                             + "+|\\d+");
+    private static final String ENCODING = "#encoding";
 
     static {
         String[] deburredLetters =
@@ -2826,8 +2827,8 @@ public static void fileJsonToXml(
         Path xmlFilePath = Paths.get(xmlFileName);
         String lineSeparator = System.lineSeparator();
         if (result instanceof Map) {
-            if (((Map) result).containsKey("#encoding")) {
-                String encoding = String.valueOf(((Map) result).get("#encoding"));
+            if (((Map) result).containsKey(ENCODING)) {
+                String encoding = String.valueOf(((Map) result).get(ENCODING));
                 Files.write(
                         xmlFilePath,
                         formatString(Xml.toXml((Map) result, identStep), lineSeparator)
@@ -2850,6 +2851,35 @@ public static void fileJsonToXml(String jsonFileName, String xmlFileName) throws
         fileJsonToXml(jsonFileName, xmlFileName, Xml.XmlStringBuilder.Step.TWO_SPACES);
     }
 
+    public static void streamJsonToXml(
+            InputStream jsonInputStream,
+            OutputStream xmlOutputStream,
+            Xml.XmlStringBuilder.Step identStep)
+            throws IOException {
+        byte[] bytes = jsonInputStream.readAllBytes();
+        String jsonText = new String(removeBom(bytes), detectEncoding(bytes));
+        Object jsonObject = U.fromJson(jsonText);
+        String lineSeparator = System.lineSeparator();
+        String xml;
+        if (jsonObject instanceof Map) {
+            xml = formatString(Xml.toXml((Map<?, ?>) jsonObject, identStep), lineSeparator);
+            if (((Map) jsonObject).containsKey(ENCODING)) {
+                String encoding = String.valueOf(((Map) jsonObject).get(ENCODING));
+                xmlOutputStream.write(xml.getBytes(encoding));
+            } else {
+                xmlOutputStream.write(xml.getBytes(StandardCharsets.UTF_8));
+            }
+        } else {
+            xml = formatString(Xml.toXml((List<?>) jsonObject, identStep), lineSeparator);
+            xmlOutputStream.write(xml.getBytes(StandardCharsets.UTF_8));
+        }
+    }
+
+    public static void streamJsonToXml(InputStream jsonInputStream, OutputStream xmlOutputStream)
+            throws IOException {
+        streamJsonToXml(jsonInputStream, xmlOutputStream, Xml.XmlStringBuilder.Step.TWO_SPACES);
+    }
+
     public static byte[] removeBom(byte[] bytes) {
         if ((bytes.length >= 3) && (bytes[0] == -17) && (bytes[1] == -69) && (bytes[2] == -65)) {
             return Arrays.copyOfRange(bytes, 3, bytes.length);

src/test/java/com/github/underscore/UnderscoreTest.java

@@ -1226,4 +1226,86 @@ void testListResult(@TempDir Path tempDir) throws IOException {
                 xmlStr,
                 "Should write XML using UTF-8 when result is a List");
     }
+
+    @Test
+    void testStreamJsonToXml_ObjectMap_DefaultEncoding() throws Exception {
+        String inputJson = "{\"root\":\"value\"}";
+        ByteArrayInputStream inputStream =
+                new ByteArrayInputStream(inputJson.getBytes(StandardCharsets.UTF_8));
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        U.streamJsonToXml(inputStream, outputStream);
+        String expectedXml =
+                "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
+                        + System.lineSeparator()
+                        + "<root>value</root>";
+        String actualXml = outputStream.toString(StandardCharsets.UTF_8);
+        assertEquals(
+                expectedXml,
+                actualXml,
+                "XML output should match expected XML for simple JSON object with default encoding");
+    }
+
+    @Test
+    void testStreamJsonToXml_ObjectMap_CustomEncoding() throws Exception {
+        String inputJson = "{\"root\":\"value\",\"#encoding\":\"UTF-16\"}";
+        ByteArrayInputStream inputStream =
+                new ByteArrayInputStream(inputJson.getBytes(StandardCharsets.UTF_8));
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        U.streamJsonToXml(inputStream, outputStream, Xml.XmlStringBuilder.Step.TWO_SPACES);
+        String expectedXml =
+                "<?xml version=\"1.0\" encoding=\"UTF-16\"?>"
+                        + System.lineSeparator()
+                        + "<root>value</root>";
+        String actualXml = outputStream.toString(StandardCharsets.UTF_16);
+        assertEquals(
+                expectedXml,
+                actualXml,
+                "XML output should match expected XML for simple JSON object with default encoding");
+    }
+
+    @Test
+    void testStreamJsonToXml_List() throws Exception {
+        String inputJson = "[{\"item\":42}]";
+        ByteArrayInputStream inputStream =
+                new ByteArrayInputStream(inputJson.getBytes(StandardCharsets.UTF_8));
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        U.streamJsonToXml(inputStream, outputStream, Xml.XmlStringBuilder.Step.TWO_SPACES);
+        String expectedXml =
+                "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
+                        + System.lineSeparator()
+                        + "<root>"
+                        + System.lineSeparator()
+                        + "  <element array=\"true\">"
+                        + System.lineSeparator()
+                        + "    <item number=\"true\">42</item>"
+                        + System.lineSeparator()
+                        + "  </element>"
+                        + System.lineSeparator()
+                        + "</root>";
+        String actualXml = outputStream.toString(StandardCharsets.UTF_8);
+        assertEquals(
+                expectedXml,
+                actualXml,
+                "XML output should match expected XML for JSON array root with default encoding");
+    }
+
+    @Test
+    void testStreamJsonToXml_InvalidJson_ThrowsException() {
+        String inputJson = "invalid";
+        ByteArrayInputStream inputStream =
+                new ByteArrayInputStream(inputJson.getBytes(StandardCharsets.UTF_8));
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        Exception exception =
+                assertThrows(
+                        Json.ParseException.class,
+                        () ->
+                                U.streamJsonToXml(
+                                        inputStream,
+                                        outputStream,
+                                        Xml.XmlStringBuilder.Step.TWO_SPACES));
+        String actualMessage = exception.getMessage();
+        assertTrue(
+                actualMessage.contains("Expected value"),
+                "Should throw exception if JSON is invalid");
+    }
 }