BAEL-6310 - guide to JacksonJr

This commit is contained in:
tudor.marc 2023-06-13 01:00:38 +03:00
parent 25364556e5
commit d902e26e85
8 changed files with 288 additions and 0 deletions

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jackson-jr/pom.xml Normal file
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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://maven.apache.org/POM/4.0.0"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<artifactId>jackson-jr</artifactId>
<name>jackson-jr</name>
<packaging>pom</packaging>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-java</artifactId>
<version>0.0.1-SNAPSHOT</version>
<relativePath>../parent-java</relativePath>
</parent>
<dependencies>
<!--jackson jr all -->
<dependency>
<groupId>com.fasterxml.jackson.jr</groupId>
<artifactId>jackson-jr-all</artifactId>
<version>2.15.2</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.jr</groupId>
<artifactId>jackson-jr-annotation-support</artifactId>
<version>2.15.2</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>RELEASE</version>
<scope>compile</scope>
</dependency>
</dependencies>
</project>

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package com.baeldung.jacksonjr;
import com.fasterxml.jackson.jr.ob.api.ValueReader;
import com.fasterxml.jackson.jr.ob.impl.JSONReader;
import com.fasterxml.jackson.jr.private_.JsonParser;
import java.io.IOException;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
public class CustomDateDeserializer extends ValueReader {
private final static DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd");
public CustomDateDeserializer () {
super(LocalDate.class);
}
@Override
public Object read (JSONReader jsonReader, JsonParser jsonParser) throws IOException {
return LocalDate.parse(jsonParser.getText(), dtf);
}
}

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package com.baeldung.jacksonjr;
import com.fasterxml.jackson.jr.ob.api.ValueWriter;
import com.fasterxml.jackson.jr.ob.impl.JSONWriter;
import com.fasterxml.jackson.jr.private_.JsonGenerator;
import java.io.IOException;
import java.time.LocalDate;
public class CustomDateSerializer implements ValueWriter {
@Override
public void writeValue (JSONWriter jsonWriter, JsonGenerator jsonGenerator, Object o) throws IOException {
jsonGenerator.writeString(o.toString());
}
@Override
public Class<?> valueType () {
return LocalDate.class;
}
}

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package com.baeldung.jacksonjr;
import com.fasterxml.jackson.jr.annotationsupport.JacksonAnnotationExtension;
import com.fasterxml.jackson.jr.ob.JSON;
import com.fasterxml.jackson.jr.ob.JacksonJrExtension;
import com.fasterxml.jackson.jr.ob.api.ExtensionContext;
import java.io.IOException;
import java.util.LinkedHashMap;
public class JacksonJrFeatures {
public static String jsonObject() throws IOException {
return JSON.std
.with(JSON.Feature.PRETTY_PRINT_OUTPUT)
.asString(new LinkedHashMap<String, Object>() {{
put("name", "John Doe");
put("age", 30);
}});
}
public static String jsonComposer() throws IOException {
return JSON.std
.with(JSON.Feature.PRETTY_PRINT_OUTPUT)
.composeString()
.startObject()
.startArrayField("objectArray")
.startObject()
.put("name", "name1")
.put("age", 11)
.end()
.startObject()
.put("name", "name2")
.put("age", 12)
.end()
.end()
.startArrayField("array")
.add(1)
.add(2)
.add(3)
.end()
.startObjectField("object")
.put("name", "name3")
.put("age", 13)
.end()
.put("last", true)
.end()
.finish();
}
public static String objectSerialization(Person person) throws IOException {
return JSON.std
.with(JSON.Feature.PRETTY_PRINT_OUTPUT)
.asString(person);
}
public static String objectAnnotationSerialization(Person person) throws IOException {
return JSON.builder()
.register(JacksonAnnotationExtension.std)
.build()
.with(JSON.Feature.PRETTY_PRINT_OUTPUT)
.asString(person);
}
public static String customObjectSerialization(Person person) throws IOException {
return JSON.builder()
.register(new JacksonJrExtension() {
@Override
protected void register (ExtensionContext extensionContext) {
extensionContext.insertProvider(new MyHandlerProvider());
}
})
.build()
.with(JSON.Feature.PRETTY_PRINT_OUTPUT)
.asString(person);
}
public static Person objectDeserialization(String json) throws IOException {
return JSON.std
.with(JSON.Feature.PRETTY_PRINT_OUTPUT)
.beanFrom(Person.class, json);
}
public static Person customObjectDeserialization(String json) throws IOException {
return JSON.builder()
.register(new JacksonJrExtension() {
@Override
protected void register (ExtensionContext extensionContext) {
extensionContext.insertProvider(new MyHandlerProvider());
}
})
.build()
.with(JSON.Feature.PRETTY_PRINT_OUTPUT)
.beanFrom(Person.class, json);
}
}

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package com.baeldung.jacksonjr;
import com.fasterxml.jackson.jr.ob.api.ReaderWriterProvider;
import com.fasterxml.jackson.jr.ob.api.ValueReader;
import com.fasterxml.jackson.jr.ob.api.ValueWriter;
import com.fasterxml.jackson.jr.ob.impl.JSONReader;
import com.fasterxml.jackson.jr.ob.impl.JSONWriter;
import java.time.LocalDate;
public class MyHandlerProvider extends ReaderWriterProvider {
public ValueWriter findValueWriter (JSONWriter writeContext,
Class<?> type) {
if (type == LocalDate.class) {
return new CustomDateSerializer();
}
return null;
}
@Override
public ValueReader findValueReader (JSONReader readContext, Class<?> type) {
if (type.equals(LocalDate.class)) {
return new CustomDateDeserializer();
}
return null;
}
}

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package com.baeldung.jacksonjr;
import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.time.LocalDate;
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Person {
@JsonProperty("person_name")
private String name;
private int age;
private LocalDate birthDate;
}

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package com.baeldung.jacksonjr;
import org.junit.jupiter.api.Test;
import java.io.IOException;
import java.time.LocalDate;
import static org.junit.jupiter.api.Assertions.*;
public class JacksonJrFeaturesUnitTest {
@Test
public void whenSerializingObject_thenReturnJson() throws IOException {
String json = JacksonJrFeatures.jsonObject();
assertTrue(json.contains("name"));
assertTrue(json.contains("age"));
}
@Test
public void whenSerializingComposer_thenReturnJson() throws IOException {
String json = JacksonJrFeatures.jsonComposer();
assertTrue(json.contains("objectArray"));
assertTrue(json.contains("object"));
}
@Test
public void whenSerializingSimpleObject_thenAnnotationIsNotConsidered() throws IOException {
Person person = new Person("John Doe", 30, null);
String json = JacksonJrFeatures.objectSerialization(person);
assertTrue(json.contains("name"));
assertFalse(json.contains("person_name"));
}
@Test
public void whenDeserializingJsonObject_thenObjectsAreEqual() throws IOException {
Person person = new Person("John Doe", 30, null);
String json = JacksonJrFeatures.objectSerialization(person);
Person deserializedPerson = JacksonJrFeatures.objectDeserialization(json);
assertEquals(person, deserializedPerson);
}
@Test
public void whenSerializingWithAnnotations_thenAnnotationIsConsidered() throws IOException {
Person person = new Person("John Doe", 30, null);
String json = JacksonJrFeatures.objectAnnotationSerialization(person);
assertTrue(json.contains("person_name"));
}
@Test
public void whenSerializingCustomObject_thenLocalDateIsSerializedAsString() throws IOException {
Person person = new Person("John Doe", 30, LocalDate.now());
String json = JacksonJrFeatures.customObjectSerialization(person);
System.out.println(json);
assertTrue(json.contains("birthDate"));
}
@Test
public void whenDeserializingCustomObject_thenLocalDateIsDeserialized() throws IOException {
Person person = new Person("John Doe", 30, LocalDate.now());
String json = JacksonJrFeatures.customObjectSerialization(person);
Person deserializedPerson = JacksonJrFeatures.customObjectDeserialization(json);
assertEquals(person, deserializedPerson);
}
}

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<module>custom-pmd</module>
<module>data-structures</module>
<module>ddd-contexts</module>
<module>jackson-jr</module>
<module>jackson-modules</module>
<module>jmh</module>
<module>deeplearning4j</module>