Bael 5679 json to protobuf (#12702)

* Initial Changes

* Update ProtobufUtilUnitTest.java

* Changes for JSON to Protobuf

* Corrected the file name

* Update ProtobufUtilUnitTest.java

* Update ProtobufUtilUnitTest.java

* Update ProtobufUtilUnitTest.java

* Removed confusing changes

spring-protobuf/src/main/java/com/baeldung/protobuf/convert/ProtobufUtil.java

@@ -0,0 +1,24 @@
+package com.baeldung.protobuf.convert;
+
+import java.io.IOException;
+
+import com.google.protobuf.AbstractMessage.Builder;
+import com.google.protobuf.Message;
+import com.google.protobuf.MessageOrBuilder;
+import com.google.protobuf.Struct;
+import com.google.protobuf.util.JsonFormat;
+
+public class ProtobufUtil {
+
+    public static String toJson(MessageOrBuilder messageOrBuilder) throws IOException {
+        return JsonFormat.printer().print(messageOrBuilder);
+    }
+
+    @SuppressWarnings("unchecked")
+    public static Message fromJson(String json) throws IOException {
+        Builder structBuilder = Struct.newBuilder();
+        JsonFormat.parser().ignoringUnknownFields().merge(json, structBuilder);
+        return structBuilder.build();
+    }
+
+}

spring-protobuf/src/test/java/com/baeldung/protobuf/convert/ProtobufUtilUnitTest.java

@@ -1,13 +1,7 @@
 package com.baeldung.protobuf.convert;
 
-import java.io.BufferedReader;
-import java.io.ByteArrayInputStream;
+
 import java.io.IOException;
-import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.io.Reader;
-import java.nio.charset.Charset;
-import java.nio.charset.StandardCharsets;
 
 import org.junit.Assert;
 import org.junit.jupiter.api.Test;
@@ -16,28 +10,29 @@ import com.google.protobuf.Message;
 
 public class ProtobufUtilUnitTest {
 
-    public static String jsonInput = "{\r\n" + "  \"boolean\": true,\r\n" + "  \"color\": \"gold\",\r\n"
-            + "  \"object\": {\r\n" + "    \"a\": \"b\",\r\n" + "    \"c\": \"d\"\r\n" + "  },\r\n"
-            + "  \"string\": \"Hello World\"\r\n" + "}";
+    public static String jsonStr = "{\r\n"
+            + "  \"boolean\": true,\r\n"
+            + "  \"color\": \"gold\",\r\n"
+            + "  \"object\": {\r\n"
+            + "    \"a\": \"b\",\r\n"
+            + "    \"c\": \"d\"\r\n"
+            + "  },\r\n"
+            + "  \"string\": \"Hello World\"\r\n"
+            + "}";
+
+    @Test
+    public void givenJson_convertToProtobuf() throws IOException {
+        Message protobuf = ProtobufUtil.fromJson(jsonStr);
+        Assert.assertTrue(protobuf.toString().contains("key: \"boolean\""));
+        Assert.assertTrue(protobuf.toString().contains("string_value: \"Hello World\""));
+    }
 
     @Test
     public void givenProtobuf_convertToJson() throws IOException {
-        Message fromJson = ProtobuffUtil.fromJson(jsonInput);
-
-        InputStream inputStream = new ByteArrayInputStream(fromJson.toByteArray());
-
-        StringBuilder textBuilder = new StringBuilder();
-        try (Reader reader = new BufferedReader(
-                new InputStreamReader(inputStream, Charset.forName(StandardCharsets.UTF_8.name())))) {
-            int c = 0;
-            while ((c = reader.read()) != -1) {
-                textBuilder.append((char) c);
-            }
-        }
-        String json = ProtobuffUtil.toJson(fromJson);
+        Message protobuf = ProtobufUtil.fromJson(jsonStr);
+        String json = ProtobufUtil.toJson(protobuf);
         Assert.assertTrue(json.contains("\"boolean\": true"));
         Assert.assertTrue(json.contains("\"string\": \"Hello World\""));
         Assert.assertTrue(json.contains("\"color\": \"gold\""));
     }
-
 }