Merge pull request #15339 from Michaelin007/jackson

MismatchedInputException: Cannot deserialize instance

jackson-modules/jackson-exceptions/src/main/java/com/baeldung/mismatchedinputexception/Animals.java

@@ -0,0 +1,27 @@
+package com.baeldung.mismatchedinputexception;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public class Animals {
+
+    private final int id;
+    private String name;
+
+
+    public Animals(@JsonProperty("id") int id, @JsonProperty("name")String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

jackson-modules/jackson-exceptions/src/main/java/com/baeldung/mismatchedinputexception/Book.java

@@ -0,0 +1,27 @@
+package com.baeldung.mismatchedinputexception;
+
+public class Book {
+
+    private int id;
+    private String title;
+
+    public Book(int id, String title) {
+        this.id = id;
+        this.title = title;
+    }
+
+    public Book() {
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+}

jackson-modules/jackson-exceptions/src/test/java/com/baeldung/mismatchedinputexception/MismatchedinputExceptionUnitTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.mismatchedinputexception;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class MismatchedinputExceptionUnitTest {
+
+    @Test
+    void givenJsonString_whenDeserializingToJavaObjectWithImmutableField_thenIdIsCorrect() throws JsonProcessingException {
+        String jsonString = "{\"id\":10,\"name\":\"Dog\"}";
+        ObjectMapper mapper = new ObjectMapper();
+        Animals animal = mapper.readValue(jsonString, Animals.class);
+        assertEquals(animal.getId(),10);
+    }
+
+    @Test
+    void givenJsonString_whenDeserializingToBook_thenIdIsCorrect() throws JsonProcessingException {
+        String jsonString = "{\"id\":\"10\",\"title\":\"Harry Potter\"}";
+        ObjectMapper mapper = new ObjectMapper();
+        Book book = mapper.readValue(jsonString, Book.class);
+        assertEquals(book.getId(),10);
+    }
+
+
+    @Test
+    void givenJsonString_whenDeserializingToBookList_thenTitleIsCorrect() throws JsonProcessingException {
+        String jsonString = "[{\"id\":\"10\",\"title\":\"Harry Potter\"}]";
+        ObjectMapper mapper = new ObjectMapper();
+        List<Book> book = mapper.readValue(jsonString, new TypeReference<List<Book>>(){});
+        assertEquals(book.get(0).getTitle(),"Harry Potter");
+    }
+
+}