Bael 2721 - JSON deserialization mapping different JSON fields to same Java field (#6434)

* BAEL-2721 Examples of @JsonAlias and Gson's alternate parameter

* BAEL-2721 Update class and method names for JsonAlias and GsonAlternate

gson/src/main/java/org/baeldung/gson/entities/Weather.java

@@ -0,0 +1,40 @@
+package org.baeldung.gson.entities;
+
+import com.google.gson.annotations.SerializedName;
+
+public class Weather {
+
+    @SerializedName(value = "location", alternate = "place")
+    private String location;
+
+    @SerializedName(value = "temp", alternate = "temperature")
+    private int temp;
+
+    @SerializedName(value = "outlook", alternate = "weather")
+    private String outlook;
+
+    public String getLocation() {
+        return location;
+    }
+
+    public void setLocation(String location) {
+        this.location = location;
+    }
+
+    public int getTemp() {
+        return temp;
+    }
+
+    public void setTemp(int temp) {
+        this.temp = temp;
+    }
+
+    public String getOutlook() {
+        return outlook;
+    }
+
+    public void setOutlook(String outlook) {
+        this.outlook = outlook;
+    }
+
+}

gson/src/test/java/org/baeldung/gson/deserialization/GsonAlternateUnitTest.java

@@ -0,0 +1,39 @@
+package org.baeldung.gson.deserialization;
+
+import static org.junit.Assert.assertEquals;
+
+import org.baeldung.gson.entities.Weather;
+import org.junit.Test;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+
+public class GsonAlternateUnitTest {
+
+    @Test
+    public void givenTwoJsonFormats_whenDeserialized_thenWeatherObjectsCreated() throws Exception {
+
+        Gson gson = new GsonBuilder().create();
+
+        Weather weather = gson.fromJson("{" + 
+            "\"location\": \"London\"," + 
+            "\"temp\": 15," + 
+            "\"weather\": \"Cloudy\"" + 
+            "}", Weather.class);
+
+        assertEquals("London", weather.getLocation());
+        assertEquals("Cloudy", weather.getOutlook());
+        assertEquals(15, weather.getTemp());
+
+        weather = gson.fromJson("{" + 
+            "\"place\": \"Lisbon\"," + 
+            "\"temperature\": 35," + 
+            "\"outlook\": \"Sunny\"" + 
+            "}", Weather.class);
+
+        assertEquals("Lisbon", weather.getLocation());
+        assertEquals("Sunny", weather.getOutlook());
+        assertEquals(35, weather.getTemp());
+
+    }
+}

jackson/src/main/java/com/baeldung/jackson/entities/Weather.java

@@ -0,0 +1,44 @@
+package com.baeldung.jackson.entities;
+
+import com.fasterxml.jackson.annotation.JsonAlias;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public class Weather {
+
+    @JsonProperty("location")
+    @JsonAlias("place")
+    private String location;
+
+    @JsonProperty("temp")
+    @JsonAlias("temperature")
+    private int temp;
+
+    @JsonProperty("outlook")
+    @JsonAlias("weather")
+    private String outlook;
+
+    public String getLocation() {
+        return location;
+    }
+
+    public void setLocation(String location) {
+        this.location = location;
+    }
+
+    public int getTemp() {
+        return temp;
+    }
+
+    public void setTemp(int temp) {
+        this.temp = temp;
+    }
+
+    public String getOutlook() {
+        return outlook;
+    }
+
+    public void setOutlook(String outlook) {
+        this.outlook = outlook;
+    }
+
+}

jackson/src/test/java/com/baeldung/jackson/deserialization/jsonalias/JsonAliasUnitTest.java

@@ -0,0 +1,38 @@
+package com.baeldung.jackson.deserialization.jsonalias;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import com.baeldung.jackson.entities.Weather;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+public class JsonAliasUnitTest {
+
+    @Test
+    public void givenTwoJsonFormats_whenDeserialized_thenWeatherObjectsCreated() throws Exception {
+
+        ObjectMapper mapper = new ObjectMapper();
+
+        Weather weather = mapper.readValue("{" + 
+            "\"location\": \"London\"," + 
+            "\"temp\": 15," + 
+            "\"weather\": \"Cloudy\"" + 
+            "}", Weather.class);
+
+        assertEquals("London", weather.getLocation());
+        assertEquals("Cloudy", weather.getOutlook());
+        assertEquals(15, weather.getTemp());
+
+        weather = mapper.readValue("{" + 
+            "\"place\": \"Lisbon\"," + 
+            "\"temperature\": 35," + 
+            "\"outlook\": \"Sunny\"" + 
+            "}", Weather.class);
+
+        assertEquals("Lisbon", weather.getLocation());
+        assertEquals("Sunny", weather.getOutlook());
+        assertEquals(35, weather.getTemp());
+
+    }
+}