Fix #1911

Author: cowtowncoder

release-notes/VERSION-2.x

@@ -4,6 +4,12 @@ Project: jackson-databind
 === Releases === 
 ------------------------------------------------------------------------
 
+2.9.5 (not released yet)
+
+#1911: Allow serialization of `BigDecimal` as String, using
+  `@JsonFormat(shape=Shape.String)`, config overrides
+ (suggested by cen1@github)
+
 2.9.4 (24-Jan-2018)
 
 #1382: `@JsonProperty(access=READ_ONLY)` unxepected behaviour with `Collections`

src/main/java/com/fasterxml/jackson/databind/ser/std/NumberSerializer.java

@@ -5,11 +5,13 @@
 import java.math.BigDecimal;
 import java.math.BigInteger;
 
+import com.fasterxml.jackson.annotation.JsonFormat;
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;
 import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper;
+import com.fasterxml.jackson.databind.ser.ContextualSerializer;
 
 /**
  * As a fallback, we may need to use this serializer for other
@@ -20,6 +22,7 @@
 @SuppressWarnings("serial")
 public class NumberSerializer
     extends StdScalarSerializer<Number>
+    implements ContextualSerializer
 {
     /**
      * Static instance that is only to be used for {@link java.lang.Number}.
@@ -37,6 +40,21 @@ public NumberSerializer(Class<? extends Number> rawType) {
         _isInt = (rawType == BigInteger.class);
     }
 
+    @Override
+    public JsonSerializer<?> createContextual(SerializerProvider prov,
+            BeanProperty property) throws JsonMappingException
+    {
+        JsonFormat.Value format = findFormatOverrides(prov, property, handledType());
+        if (format != null) {
+            switch (format.getShape()) {
+            case STRING:
+                return ToStringSerializer.instance;
+            default:
+            }
+        }
+        return this;
+    }
+
     @Override
     public void serialize(Number value, JsonGenerator g, SerializerProvider provider) throws IOException
     {

src/test/java/com/fasterxml/jackson/databind/ser/jdk/NumberSerTest.java

@@ -19,10 +19,19 @@ public class NumberSerTest extends BaseMapTest
 
     static class IntWrapper {
         public int i;
-
         public IntWrapper(int value) { i = value; }
     }
-    
+
+    static class DoubleWrapper {
+        public double value;
+        public DoubleWrapper(double v) { value = v; }
+    }
+
+    static class BigDecimalWrapper {
+        public BigDecimal value;
+        public BigDecimalWrapper(BigDecimal v) { value = v; }
+    }
+
     static class IntAsString {
         @JsonFormat(shape=JsonFormat.Shape.STRING)
         @JsonProperty("value")
@@ -39,6 +48,16 @@ static class DoubleAsString {
         public double value = -0.5;
     }
 
+    static class BigIntegerAsString {
+        @JsonFormat(shape=JsonFormat.Shape.STRING)
+        public BigInteger value = BigInteger.valueOf(123456L);
+    }
+
+    static class BigDecimalAsString {
+        @JsonFormat(shape=JsonFormat.Shape.STRING)
+        public BigDecimal value = BigDecimal.valueOf(0.25);
+    }
+    
     static class NumberWrapper {
         // ensure it will use `Number` as statically force type, when looking for serializer
         @JsonSerialize(as=Number.class)
@@ -87,15 +106,26 @@ public void testNumbersAsString() throws Exception
         assertEquals(aposToQuotes("{'value':'3'}"), MAPPER.writeValueAsString(new IntAsString()));
         assertEquals(aposToQuotes("{'value':'4'}"), MAPPER.writeValueAsString(new LongAsString()));
         assertEquals(aposToQuotes("{'value':'-0.5'}"), MAPPER.writeValueAsString(new DoubleAsString()));
+        assertEquals(aposToQuotes("{'value':'0.25'}"), MAPPER.writeValueAsString(new BigDecimalAsString()));
+        assertEquals(aposToQuotes("{'value':'123456'}"), MAPPER.writeValueAsString(new BigIntegerAsString()));
     }
 
     public void testConfigOverridesForNumbers() throws Exception
     {
         ObjectMapper mapper = new ObjectMapper();
         mapper.configOverride(Integer.TYPE) // for `int`
             .setFormat(JsonFormat.Value.forShape(JsonFormat.Shape.STRING));
+        mapper.configOverride(Double.TYPE) // for `double`
+            .setFormat(JsonFormat.Value.forShape(JsonFormat.Shape.STRING));
+        mapper.configOverride(BigDecimal.class)
+            .setFormat(JsonFormat.Value.forShape(JsonFormat.Shape.STRING));
+
         assertEquals(aposToQuotes("{'i':'3'}"),
                 mapper.writeValueAsString(new IntWrapper(3)));
+        assertEquals(aposToQuotes("{'value':'0.75'}"),
+                mapper.writeValueAsString(new DoubleWrapper(0.75)));
+        assertEquals(aposToQuotes("{'value':'-0.5'}"),
+                mapper.writeValueAsString(new BigDecimalWrapper(BigDecimal.valueOf(-0.5))));
     }
 
     public void testNumberType() throws Exception