BAEL-5193-Deserialize Snake Case With Jackson (#11341)

* BAEL-5193-deserialize-snake-case

* refactor

* refactor

Co-authored-by: tienvn4 <tienvn4@ghtk.co>

jackson-modules/jackson-conversions-2/src/main/java/com/baeldung/jackson/snakecase/User.java

@@ -0,0 +1,22 @@
+package com.baeldung.jackson.snakecase;
+
+public class User {
+    private String firstName;
+    private String lastName;
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+}

jackson-modules/jackson-conversions-2/src/main/java/com/baeldung/jackson/snakecase/UserWithPropertyNames.java

@@ -0,0 +1,26 @@
+package com.baeldung.jackson.snakecase;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public class UserWithPropertyNames {
+    @JsonProperty("first_name")
+    private String firstName;
+    @JsonProperty("last_name")
+    private String lastName;
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+}

jackson-modules/jackson-conversions-2/src/main/java/com/baeldung/jackson/snakecase/UserWithSnakeStrategy.java

@@ -0,0 +1,26 @@
+package com.baeldung.jackson.snakecase;
+
+import com.fasterxml.jackson.databind.PropertyNamingStrategy;
+import com.fasterxml.jackson.databind.annotation.JsonNaming;
+
+@JsonNaming(PropertyNamingStrategy.SnakeCaseStrategy.class)
+public class UserWithSnakeStrategy {
+    private String firstName;
+    private String lastName;
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+}

jackson-modules/jackson-conversions-2/src/test/java/com/baeldung/jackson/snakecase/SnakeCaseUnitTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.jackson.snakecase;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.PropertyNamingStrategy;
+import com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class SnakeCaseUnitTest {
+
+    private static final String JSON = "{\"first_name\": \"Jackie\", \"last_name\": \"Chan\"}";
+
+    @Test(expected = UnrecognizedPropertyException.class)
+    public void whenExceptionThrown_thenExpectationSatisfied() throws Exception {
+        ObjectMapper objectMapper = new ObjectMapper();
+        objectMapper.readValue(JSON, User.class);
+    }
+
+    @Test
+    public void givenSnakeCaseJson_whenParseWithJsonPropertyAnnotation_thenGetExpectedObject() throws Exception {
+        ObjectMapper objectMapper = new ObjectMapper();
+        UserWithPropertyNames user = objectMapper.readValue(JSON, UserWithPropertyNames.class);
+        assertEquals("Jackie", user.getFirstName());
+        assertEquals("Chan", user.getLastName());
+    }
+
+    @Test
+    public void givenSnakeCaseJson_whenParseWithJsonNamingAnnotation_thenGetExpectedObject() throws Exception {
+        ObjectMapper objectMapper = new ObjectMapper();
+        UserWithSnakeStrategy user = objectMapper.readValue(JSON, UserWithSnakeStrategy.class);
+        assertEquals("Jackie", user.getFirstName());
+        assertEquals("Chan", user.getLastName());
+    }
+
+    @Test
+    public void givenSnakeCaseJson_whenParseWithCustomMapper_thenGetExpectedObject() throws Exception {
+        ObjectMapper objectMapper = new ObjectMapper().setPropertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);
+        User user = objectMapper.readValue(JSON, User.class);
+        assertEquals("Jackie", user.getFirstName());
+        assertEquals("Chan", user.getLastName());
+    }
+
+}