diff --git a/jackson-2/src/main/java/com/baeldung/jackson/entities/File.java b/jackson-2/src/main/java/com/baeldung/jackson/entities/File.java new file mode 100644 index 0000000000..0e8829e927 --- /dev/null +++ b/jackson-2/src/main/java/com/baeldung/jackson/entities/File.java @@ -0,0 +1,25 @@ +package com.baeldung.jackson.entities; + +public class File { + + private Long id; + + private String name; + + public Long getId() { + return id; + } + + public void setId(Long id) { + this.id = id; + } + + public String getName() { + return name; + } + + public void setName(String name) { + this.name = name; + } + +} \ No newline at end of file diff --git a/jackson-2/src/main/java/com/baeldung/jackson/entities/Folder.java b/jackson-2/src/main/java/com/baeldung/jackson/entities/Folder.java new file mode 100644 index 0000000000..c49e46b204 --- /dev/null +++ b/jackson-2/src/main/java/com/baeldung/jackson/entities/Folder.java @@ -0,0 +1,82 @@ +package com.baeldung.jackson.entities; + +import java.util.ArrayList; +import java.util.Date; +import java.util.List; + +import com.fasterxml.jackson.annotation.JsonIgnore; + +public class Folder { + + private Long id; + + private String name; + + private String owner; + + private Date created; + + private Date modified; + + private Date lastAccess; + + @JsonIgnore + private List files = new ArrayList<>(); + + public Long getId() { + return id; + } + + public void setId(Long id) { + this.id = id; + } + + public String getName() { + return name; + } + + public void setName(String name) { + this.name = name; + } + + public String getOwner() { + return owner; + } + + public void setOwner(String owner) { + this.owner = owner; + } + + public Date getCreated() { + return created; + } + + public void setCreated(Date created) { + this.created = created; + } + + public Date getModified() { + return modified; + } + + public void setModified(Date modified) { + this.modified = modified; + } + + public Date getLastAccess() { + return lastAccess; + } + + public void setLastAccess(Date lastAccess) { + this.lastAccess = lastAccess; + } + + public List getFiles() { + return files; + } + + public void setFiles(List files) { + this.files = files; + } + +} \ No newline at end of file diff --git a/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderBeanSerializerModifier.java b/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderBeanSerializerModifier.java new file mode 100644 index 0000000000..a3add58dc4 --- /dev/null +++ b/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderBeanSerializerModifier.java @@ -0,0 +1,21 @@ +package com.baeldung.jackson.serialization.custom.serializer; + +import com.baeldung.jackson.entities.Folder; +import com.fasterxml.jackson.databind.BeanDescription; +import com.fasterxml.jackson.databind.JsonSerializer; +import com.fasterxml.jackson.databind.SerializationConfig; +import com.fasterxml.jackson.databind.ser.BeanSerializerModifier; + +public class FolderBeanSerializerModifier extends BeanSerializerModifier { + + @Override + public JsonSerializer modifySerializer(SerializationConfig config, BeanDescription beanDesc, JsonSerializer serializer) { + + if (beanDesc.getBeanClass().equals(Folder.class)) { + return new FolderSerializerWithDefaultSerializerStored((JsonSerializer) serializer); + } + + return serializer; + } + +} diff --git a/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializer.java b/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializer.java new file mode 100644 index 0000000000..f385e63e09 --- /dev/null +++ b/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializer.java @@ -0,0 +1,36 @@ +package com.baeldung.jackson.serialization.custom.serializer; + +import java.io.IOException; + +import com.baeldung.jackson.entities.File; +import com.baeldung.jackson.entities.Folder; +import com.fasterxml.jackson.core.JsonGenerator; +import com.fasterxml.jackson.databind.SerializerProvider; +import com.fasterxml.jackson.databind.ser.std.StdSerializer; + +public class FolderSerializer extends StdSerializer { + + public FolderSerializer() { + super(Folder.class); + } + + @Override + public void serialize(Folder value, JsonGenerator gen, SerializerProvider provider) throws IOException { + + gen.writeStartObject(); + gen.writeStringField("name", value.getName()); + + gen.writeArrayFieldStart("files"); + for (File file : value.getFiles()) { + gen.writeStartObject(); + gen.writeNumberField("id", file.getId()); + gen.writeStringField("name", file.getName()); + gen.writeEndObject(); + } + gen.writeEndArray(); + + gen.writeEndObject(); + + } + +} diff --git a/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializerWithCallingOwnSerializer.java b/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializerWithCallingOwnSerializer.java new file mode 100644 index 0000000000..ed5d9fffb8 --- /dev/null +++ b/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializerWithCallingOwnSerializer.java @@ -0,0 +1,30 @@ +package com.baeldung.jackson.serialization.custom.serializer; + +import java.io.IOException; + +import com.baeldung.jackson.entities.Folder; +import com.fasterxml.jackson.core.JsonGenerator; +import com.fasterxml.jackson.databind.SerializerProvider; +import com.fasterxml.jackson.databind.ser.std.StdSerializer; + +public class FolderSerializerWithCallingOwnSerializer extends StdSerializer { + + public FolderSerializerWithCallingOwnSerializer() { + super(Folder.class); + } + + @Override + public void serialize(Folder value, JsonGenerator gen, SerializerProvider provider) throws IOException { + + gen.writeStartObject(); + gen.writeStringField("name", value.getName()); + + provider.defaultSerializeField("files", value.getFiles(), gen); + + provider.defaultSerializeField("details", value, gen); + + gen.writeEndObject(); + + } + +} diff --git a/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializerWithDefaultSerializerStored.java b/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializerWithDefaultSerializerStored.java new file mode 100644 index 0000000000..d4a95cd939 --- /dev/null +++ b/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializerWithDefaultSerializerStored.java @@ -0,0 +1,35 @@ +package com.baeldung.jackson.serialization.custom.serializer; + +import java.io.IOException; + +import com.baeldung.jackson.entities.Folder; +import com.fasterxml.jackson.core.JsonGenerator; +import com.fasterxml.jackson.databind.JsonSerializer; +import com.fasterxml.jackson.databind.SerializerProvider; +import com.fasterxml.jackson.databind.ser.std.StdSerializer; + +public class FolderSerializerWithDefaultSerializerStored extends StdSerializer { + + private final JsonSerializer defaultSerializer; + + public FolderSerializerWithDefaultSerializerStored(JsonSerializer defaultSerializer) { + super(Folder.class); + this.defaultSerializer = defaultSerializer; + } + + @Override + public void serialize(Folder value, JsonGenerator gen, SerializerProvider provider) throws IOException { + + gen.writeStartObject(); + gen.writeStringField("name", value.getName()); + + provider.defaultSerializeField("files", value.getFiles(), gen); + + gen.writeFieldName("details"); + defaultSerializer.serialize(value, gen, provider); + + gen.writeEndObject(); + + } + +} diff --git a/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializerWithInternalObjectMapper.java b/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializerWithInternalObjectMapper.java new file mode 100644 index 0000000000..b23dc32205 --- /dev/null +++ b/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializerWithInternalObjectMapper.java @@ -0,0 +1,34 @@ +package com.baeldung.jackson.serialization.custom.serializer; + +import java.io.IOException; + +import com.baeldung.jackson.entities.Folder; +import com.fasterxml.jackson.core.JsonGenerator; +import com.fasterxml.jackson.databind.ObjectMapper; +import com.fasterxml.jackson.databind.SerializerProvider; +import com.fasterxml.jackson.databind.ser.std.StdSerializer; + +public class FolderSerializerWithInternalObjectMapper extends StdSerializer { + + public FolderSerializerWithInternalObjectMapper() { + super(Folder.class); + } + + @Override + public void serialize(Folder value, JsonGenerator gen, SerializerProvider provider) throws IOException { + + gen.writeStartObject(); + gen.writeStringField("name", value.getName()); + + // we access internal mapper to delegate the serialization of File list + ObjectMapper mapper = (ObjectMapper) gen.getCodec(); + + gen.writeFieldName("files"); + String stringValue = mapper.writeValueAsString(value.getFiles()); + gen.writeRawValue(stringValue); + + gen.writeEndObject(); + + } + +} diff --git a/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializerWithSerializerProvider.java b/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializerWithSerializerProvider.java new file mode 100644 index 0000000000..81990a084d --- /dev/null +++ b/jackson-2/src/main/java/com/baeldung/jackson/serialization/custom/serializer/FolderSerializerWithSerializerProvider.java @@ -0,0 +1,29 @@ +package com.baeldung.jackson.serialization.custom.serializer; + +import java.io.IOException; + +import com.baeldung.jackson.entities.Folder; +import com.fasterxml.jackson.core.JsonGenerator; +import com.fasterxml.jackson.databind.SerializerProvider; +import com.fasterxml.jackson.databind.ser.std.StdSerializer; + +public class FolderSerializerWithSerializerProvider extends StdSerializer { + + public FolderSerializerWithSerializerProvider() { + super(Folder.class); + } + + @Override + public void serialize(Folder value, JsonGenerator gen, SerializerProvider provider) throws IOException { + + gen.writeStartObject(); + gen.writeStringField("name", value.getName()); + + // we delegate the File list serialization to its default serializer + provider.defaultSerializeField("files", value.getFiles(), gen); + + gen.writeEndObject(); + + } + +} \ No newline at end of file diff --git a/jackson-2/src/test/java/com/baeldung/jackson/serialization/custom/serializer/CallingDefaultSerializerUnitTest.java b/jackson-2/src/test/java/com/baeldung/jackson/serialization/custom/serializer/CallingDefaultSerializerUnitTest.java new file mode 100644 index 0000000000..b067e7b501 --- /dev/null +++ b/jackson-2/src/test/java/com/baeldung/jackson/serialization/custom/serializer/CallingDefaultSerializerUnitTest.java @@ -0,0 +1,166 @@ +package com.baeldung.jackson.serialization.custom.serializer; + +import static org.junit.Assert.assertTrue; +import static org.junit.jupiter.api.Assertions.assertEquals; + +import java.io.IOException; +import java.time.Instant; +import java.util.ArrayList; +import java.util.Date; +import java.util.HashMap; +import java.util.List; +import java.util.Map; + +import org.junit.Before; +import org.junit.Test; + +import com.baeldung.jackson.entities.File; +import com.baeldung.jackson.entities.Folder; +import com.fasterxml.jackson.core.type.TypeReference; +import com.fasterxml.jackson.databind.ObjectMapper; +import com.fasterxml.jackson.databind.module.SimpleModule; + +public class CallingDefaultSerializerUnitTest { + + private ObjectMapper mapper; + private Folder mockFolder; + private TypeReference> mapType; + + @Before + public void setup() { + + mapType = new TypeReference>() { + }; + + mapper = new ObjectMapper(); + + mockFolder = new Folder(); + mockFolder.setId(1L); + mockFolder.setName("Root Folder"); + mockFolder.setOwner("root"); + mockFolder.setCreated(Date.from(Instant.now().minusSeconds(60))); + mockFolder.setModified(Date.from(Instant.now().minusSeconds(30))); + mockFolder.setLastAccess(Date.from(Instant.now())); + + File file1 = new File(); + file1.setId(1L); + file1.setName("File 1"); + + File file2 = new File(); + file2.setId(2L); + file2.setName("File 2"); + + List files = new ArrayList<>(); + files.add(file1); + files.add(file2); + mockFolder.setFiles(files); + + } + + @Test + public void givenFolder_whenSerialized_onlyNameAndFilesFieldsSerialized() throws IOException { + + SimpleModule module = new SimpleModule(); + module.addSerializer(new FolderSerializer()); + mapper.registerModule(module); + + String json = mapper.writeValueAsString(mockFolder); + + HashMap actual = mapper.readValue(json, mapType); + + assertTrue(actual.containsKey("name")); + assertTrue(actual.containsKey("files")); + assertEquals(mockFolder.getName(), actual.get("name")); + + List actualFiles = (List) actual.get("files"); + assertEquals(mockFolder.getFiles().size(), actualFiles.size()); + + } + + @Test + public void givenFolder_whenSerializedWithSerializerProvider_onlyNameAndFilesFieldsSerialized() throws IOException { + + SimpleModule module = new SimpleModule(); + module.addSerializer(new FolderSerializerWithSerializerProvider()); + mapper.registerModule(module); + + String json = mapper.writeValueAsString(mockFolder); + + HashMap actual = mapper.readValue(json, mapType); + + assertTrue(actual.containsKey("name")); + assertTrue(actual.containsKey("files")); + assertEquals(mockFolder.getName(), actual.get("name")); + + List actualFiles = (List) actual.get("files"); + assertEquals(mockFolder.getFiles().size(), actualFiles.size()); + + } + + @Test + public void givenFolder_whenSerializedWithInternalObjectMapper_onlyNameAndFilesFieldsSerialized() throws IOException { + + SimpleModule module = new SimpleModule(); + module.addSerializer(new FolderSerializerWithInternalObjectMapper()); + mapper.registerModule(module); + + String json = mapper.writeValueAsString(mockFolder); + + HashMap actual = mapper.readValue(json, mapType); + + assertTrue(actual.containsKey("name")); + assertTrue(actual.containsKey("files")); + assertEquals(mockFolder.getName(), actual.get("name")); + + List actualFiles = (List) actual.get("files"); + assertEquals(mockFolder.getFiles().size(), actualFiles.size()); + + } + + @Test(expected = StackOverflowError.class) + public void givenFolder_whenSerializedWithCallingOwnSerializer_exceptionOccured() throws IOException { + + SimpleModule module = new SimpleModule(); + module.addSerializer(new FolderSerializerWithCallingOwnSerializer()); + mapper.registerModule(module); + + mapper.writeValueAsString(mockFolder); + + } + + @Test + public void givenFolder_whenSerializedWithDefaultSerializerStored_NameAndFilesAndDetailsFieldsSerialized() throws IOException { + + SimpleModule module = new SimpleModule(); + module.setSerializerModifier(new FolderBeanSerializerModifier()); + mapper.registerModule(module); + + String json = mapper.writeValueAsString(mockFolder); + + HashMap actual = mapper.readValue(json, mapType); + + assertTrue(actual.containsKey("name")); + assertTrue(actual.containsKey("files")); + assertEquals(mockFolder.getName(), actual.get("name")); + + List actualFiles = (List) actual.get("files"); + assertEquals(mockFolder.getFiles().size(), actualFiles.size()); + + Map actualDetails = (Map) actual.get("details"); + assertTrue(actualDetails.containsKey("id")); + assertTrue(actualDetails.containsKey("name")); + assertTrue(actualDetails.containsKey("owner")); + assertTrue(actualDetails.containsKey("created")); + assertTrue(actualDetails.containsKey("modified")); + assertTrue(actualDetails.containsKey("lastAccess")); + + assertEquals(mockFolder.getId().longValue(), ((Number)actualDetails.get("id")).longValue()); + assertEquals(mockFolder.getName(), actualDetails.get("name")); + assertEquals(mockFolder.getOwner(), actualDetails.get("owner")); + assertEquals(mockFolder.getCreated(), new Date((long) actualDetails.get("created"))); + assertEquals(mockFolder.getModified(), new Date((long) actualDetails.get("modified"))); + assertEquals(mockFolder.getLastAccess(), new Date((long) actualDetails.get("lastAccess"))); + + } + +}