BAEL-245: Add Enum serialization example (#970)

* Add NDC and JBoss Logging to the demo application

* NDC for Log4j, Log4j2 and JBoss Logging

* Simplify NDC example by making it a single operation instead of two

* Make NDC example as RestController, Use JBoss Logging only as a logging bridge

* Fix merge conflicts in pull request - log-mdc pom.xml updated

* BAEL-445 Update to Spring security SpEL example

* BAEL-445: Change tabs to spaces in the updated code

* BAEL-245: Add Enum Serialization exmaple

* BAEL-245: Remove the folder jackson/src/test/java/com/baeldung/jackson/dtos/withEnum as the example is not used anymore

jackson/src/main/java/com/baeldung/jackson/enums/Distance.java

@@ -0,0 +1,54 @@
+package com.baeldung.jackson.enums;
+
+import com.baeldung.jackson.serialization.DistanceSerializer;
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
+
+/**
+ * Use  @JsonFormat to handle representation of Enum as JSON (available since Jackson 2.1.2)
+ * Use @JsonSerialize to configure a custom Jackson serializer
+ */
+// @JsonFormat(shape = JsonFormat.Shape.OBJECT)
+@JsonSerialize(using = DistanceSerializer.class)
+public enum Distance {
+    KILOMETER("km", 1000), MILE("miles", 1609.34), METER("meters", 1), INCH("inches", 0.0254), CENTIMETER("cm", 0.01), MILLIMETER("mm", 0.001);
+
+    private String unit;
+    private final double meters;
+
+    private Distance(String unit, double meters) {
+        this.unit = unit;
+        this.meters = meters;
+    }
+
+    /**
+     * Use @JsonValue to control marshalling output for an enum
+     */
+    // @JsonValue
+    public double getMeters() {
+        return meters;
+    }
+
+    public String getUnit() {
+        return unit;
+    }
+
+    public void setUnit(String unit) {
+        this.unit = unit;
+    }
+
+    /**
+     * Usage example: Distance.MILE.convertFromMeters(1205.5);
+     */
+    public double convertFromMeters(double distanceInMeters) {
+        return distanceInMeters / meters;
+
+    }
+
+    /**
+     * Usage example: Distance.MILE.convertToMeters(0.5);
+     */
+    public double convertToMeters(double distanceInMeters) {
+        return distanceInMeters * meters;
+    }
+
+}

jackson/src/main/java/com/baeldung/jackson/serialization/DistanceSerializer.java

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+package com.baeldung.jackson.serialization;
+
+import java.io.IOException;
+
+import com.baeldung.jackson.enums.Distance;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.fasterxml.jackson.databind.ser.std.StdSerializer;
+
+public class DistanceSerializer extends StdSerializer<Distance> {
+
+    private static final long serialVersionUID = 1376504304439963619L;
+
+    public DistanceSerializer() {
+        super(Distance.class);
+    }
+
+    public DistanceSerializer(Class<Distance> t) {
+        super(t);
+    }
+
+    public void serialize(Distance distance, JsonGenerator generator, SerializerProvider provider) throws IOException, JsonProcessingException {
+        generator.writeStartObject();
+        generator.writeFieldName("name");
+        generator.writeNumber(distance.name());
+        generator.writeFieldName("unit");
+        generator.writeString(distance.getUnit());
+        generator.writeFieldName("meters");
+        generator.writeNumber(distance.getMeters());
+        generator.writeEndObject();
+    }
+}