Add JacksonExceptions Test

jackson/src/test/java/org/baeldung/jackson/exception/User.java

@@ -0,0 +1,11 @@
+package org.baeldung.jackson.exception;
+
+public class User {
+    public int id;
+    public String name;
+
+    public User(final int id, final String name) {
+        this.id = id;
+        this.name = name;
+    }
+}

jackson/src/test/java/org/baeldung/jackson/exception/UserWithConflict.java

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+package org.baeldung.jackson.exception;
+
+public class UserWithConflict {
+    public int id;
+    public String name;
+    boolean checked;
+
+    public UserWithConflict() {
+        super();
+    }
+
+    public UserWithConflict(final int id, final String name, final boolean checked) {
+        this.id = id;
+        this.name = name;
+        this.checked = checked;
+    }
+
+    public boolean getChecked() {
+        return checked;
+    }
+
+    public boolean isChecked() {
+        return checked;
+    }
+}

jackson/src/test/java/org/baeldung/jackson/exception/UserWithPrivateFields.java

@@ -0,0 +1,16 @@
+package org.baeldung.jackson.exception;
+
+public class UserWithPrivateFields {
+    int id;
+    String name;
+
+    public UserWithPrivateFields() {
+        super();
+    }
+
+    public UserWithPrivateFields(final int id, final String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+}

jackson/src/test/java/org/baeldung/jackson/exception/UserWithRoot.java

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+package org.baeldung.jackson.exception;
+
+import com.fasterxml.jackson.annotation.JsonRootName;
+
+@JsonRootName(value = "user")
+public class UserWithRoot {
+    public int id;
+    public String name;
+
+    public UserWithRoot() {
+        super();
+    }
+
+    public UserWithRoot(final int id, final String name) {
+        this.id = id;
+        this.name = name;
+    }
+}

jackson/src/test/java/org/baeldung/jackson/exception/Zoo.java

@@ -0,0 +1,19 @@
+package org.baeldung.jackson.exception;
+
+public class Zoo {
+    public Animal animal;
+}
+
+abstract class Animal {
+    public String name;
+
+    protected Animal() {
+    }
+}
+
+class Cat extends Animal {
+    public int lives;
+
+    public Cat() {
+    }
+}

jackson/src/test/java/org/baeldung/jackson/exception/ZooConfigured.java

@@ -0,0 +1,22 @@
+package org.baeldung.jackson.exception;
+
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+
+public class ZooConfigured {
+    public AnimalConfigured animal;
+}
+
+@JsonDeserialize(as = CatConfigured.class)
+abstract class AnimalConfigured {
+    public String name;
+
+    protected AnimalConfigured() {
+    }
+}
+
+class CatConfigured extends AnimalConfigured {
+    public int lives;
+
+    public CatConfigured() {
+    }
+}

jackson/src/test/java/org/baeldung/jackson/test/JacksonExceptionsTest.java

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+package org.baeldung.jackson.test;
+
+import static org.hamcrest.Matchers.containsString;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.baeldung.jackson.dtos.User;
+import org.baeldung.jackson.exception.UserWithPrivateFields;
+import org.baeldung.jackson.exception.UserWithRoot;
+import org.baeldung.jackson.exception.Zoo;
+import org.baeldung.jackson.exception.ZooConfigured;
+import org.junit.Test;
+
+import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
+import com.fasterxml.jackson.annotation.PropertyAccessor;
+import com.fasterxml.jackson.core.JsonFactory;
+import com.fasterxml.jackson.core.JsonParseException;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.JsonMappingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException;
+
+public class JacksonExceptionsTest {
+
+    // JsonMappingException: Can not construct instance of
+    @Test(expected = JsonMappingException.class)
+    public void givenAbstractClass_whenDeserializing_thenException() throws IOException {
+        final String json = "{\"animal\":{\"name\":\"lacy\"}}";
+        final ObjectMapper mapper = new ObjectMapper();
+
+        mapper.reader().withType(Zoo.class).readValue(json);
+    }
+
+    @Test
+    public void givenAbstractClassConfigured_whenDeserializing_thenCorrect() throws IOException {
+        final String json = "{\"animal\":{\"name\":\"lacy\"}}";
+        final ObjectMapper mapper = new ObjectMapper();
+
+        mapper.reader().withType(ZooConfigured.class).readValue(json);
+    }
+
+    // JsonMappingException: No serializer found for class
+    @Test(expected = JsonMappingException.class)
+    public void givenClassWithPrivateFields_whenSerializing_thenException() throws IOException {
+        final UserWithPrivateFields user = new UserWithPrivateFields(1, "John");
+
+        final ObjectMapper mapper = new ObjectMapper();
+        mapper.writer().writeValueAsString(user);
+    }
+
+    @Test
+    public void givenClassWithPrivateFields_whenConfigureSerializing_thenCorrect() throws IOException {
+        final UserWithPrivateFields user = new UserWithPrivateFields(1, "John");
+
+        final ObjectMapper mapper = new ObjectMapper();
+        mapper.setVisibility(PropertyAccessor.FIELD, Visibility.ANY);
+
+        final String result = mapper.writer().writeValueAsString(user);
+        assertThat(result, containsString("John"));
+    }
+
+    // JsonMappingException: No suitable constructor found
+    @Test(expected = JsonMappingException.class)
+    public void givenNoDefaultConstructor_whenDeserializing_thenException() throws IOException {
+        final String json = "{\"id\":1,\"name\":\"John\"}";
+        final ObjectMapper mapper = new ObjectMapper();
+
+        mapper.reader().withType(org.baeldung.jackson.exception.User.class).readValue(json);
+    }
+
+    @Test
+    public void givenDefaultConstructor_whenDeserializing_thenCorrect() throws IOException {
+        final String json = "{\"id\":1,\"name\":\"John\"}";
+        final ObjectMapper mapper = new ObjectMapper();
+
+        final User user = mapper.reader().withType(User.class).readValue(json);
+        assertEquals("John", user.name);
+    }
+
+    // JsonMappingException: Root name does not match expected
+    @Test(expected = JsonMappingException.class)
+    public void givenWrappedJsonString_whenDeserializing_thenException() throws IOException {
+        final String json = "{\"user\":{\"id\":1,\"name\":\"John\"}}";
+
+        final ObjectMapper mapper = new ObjectMapper();
+        mapper.enable(DeserializationFeature.UNWRAP_ROOT_VALUE);
+
+        mapper.reader().withType(User.class).readValue(json);
+    }
+
+    @Test
+    public void givenWrappedJsonStringAndConfigureClass_whenDeserializing_thenCorrect() throws IOException {
+        final String json = "{\"user\":{\"id\":1,\"name\":\"John\"}}";
+
+        final ObjectMapper mapper = new ObjectMapper();
+        mapper.enable(DeserializationFeature.UNWRAP_ROOT_VALUE);
+
+        final UserWithRoot user = mapper.reader().withType(UserWithRoot.class).readValue(json);
+        assertEquals("John", user.name);
+    }
+
+    // JsonMappingException: Can not deserialize instance of
+    @Test(expected = JsonMappingException.class)
+    public void givenJsonOfArray_whenDeserializing_thenException() throws JsonProcessingException, IOException {
+        final String json = "[{\"id\":1,\"name\":\"John\"},{\"id\":2,\"name\":\"Adam\"}]";
+        final ObjectMapper mapper = new ObjectMapper();
+
+        mapper.reader().withType(User.class).readValue(json);
+    }
+
+    @Test
+    public void givenJsonOfArray_whenDeserializing_thenCorrect() throws JsonProcessingException, IOException {
+        final String json = "[{\"id\":1,\"name\":\"John\"},{\"id\":2,\"name\":\"Adam\"}]";
+        final ObjectMapper mapper = new ObjectMapper();
+
+        final List<User> users = mapper.reader().withType(new TypeReference<List<User>>() {
+        }).readValue(json);
+
+        assertEquals(2, users.size());
+    }
+
+    // UnrecognizedPropertyException
+    @Test(expected = UnrecognizedPropertyException.class)
+    public void givenJsonStringWithExtra_whenDeserializing_thenException() throws IOException {
+        final String json = "{\"id\":1,\"name\":\"John\", \"checked\":true}";
+
+        final ObjectMapper mapper = new ObjectMapper();
+        mapper.reader().withType(User.class).readValue(json);
+    }
+
+    @Test
+    public void givenJsonStringWithExtra_whenConfigureDeserializing_thenCorrect() throws IOException {
+        final String json = "{\"id\":1,\"name\":\"John\", \"checked\":true}";
+
+        final ObjectMapper mapper = new ObjectMapper();
+        mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
+
+        final User user = mapper.reader().withType(User.class).readValue(json);
+        assertEquals("John", user.name);
+    }
+
+    // JsonParseException: Unexpected character (''' (code 39))
+    @Test(expected = JsonParseException.class)
+    public void givenStringWithSingleQuotes_whenDeserializing_thenException() throws JsonProcessingException, IOException {
+        final String json = "{'id':1,'name':'John'}";
+        final ObjectMapper mapper = new ObjectMapper();
+
+        mapper.reader().withType(User.class).readValue(json);
+    }
+
+    @Test
+    public void givenStringWithSingleQuotes_whenConfigureDeserializing_thenCorrect() throws JsonProcessingException, IOException {
+        final String json = "{'id':1,'name':'John'}";
+
+        final JsonFactory factory = new JsonFactory();
+        factory.enable(JsonParser.Feature.ALLOW_SINGLE_QUOTES);
+        final ObjectMapper mapper = new ObjectMapper(factory);
+
+        final User user = mapper.reader().withType(User.class).readValue(json);
+        assertEquals("John", user.name);
+    }
+
+
+
+}