Java tutorial
/* * Copyright 2013-2019 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.integration.support.json; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.Reader; import java.io.Writer; import java.lang.reflect.Type; import java.net.URL; import java.util.Collection; import java.util.Map; import org.springframework.beans.BeanUtils; import org.springframework.integration.mapping.support.JsonHeaders; import org.springframework.util.Assert; import org.springframework.util.ClassUtils; import com.fasterxml.jackson.core.JsonParseException; import com.fasterxml.jackson.core.JsonParser; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.DeserializationFeature; import com.fasterxml.jackson.databind.JavaType; import com.fasterxml.jackson.databind.JsonNode; import com.fasterxml.jackson.databind.MapperFeature; import com.fasterxml.jackson.databind.Module; import com.fasterxml.jackson.databind.ObjectMapper; /** * Jackson 2 JSON-processor (@link https://github.com/FasterXML) * {@linkplain JsonObjectMapper} implementation. * Delegates <code>toJson</code> and <code>fromJson</code> * to the {@linkplain com.fasterxml.jackson.databind.ObjectMapper} * <p> * It customizes Jackson's default properties with the following ones: * <ul> * <li>{@link MapperFeature#DEFAULT_VIEW_INCLUSION} is disabled</li> * <li>{@link DeserializationFeature#FAIL_ON_UNKNOWN_PROPERTIES} is disabled</li> * <li>The well-known modules are registered through the classpath scan</li> * </ul> * * See {@code org.springframework.http.converter.json.Jackson2ObjectMapperBuilder} * in the spring-web for more information. * * @author Artem Bilan * @author Vikas Prasad * * @since 3.0 * */ public class Jackson2JsonObjectMapper extends AbstractJacksonJsonObjectMapper<JsonNode, JsonParser, JavaType> { private static final String UNUSED = "unused"; private final ObjectMapper objectMapper; public Jackson2JsonObjectMapper() { this.objectMapper = new ObjectMapper(); this.objectMapper.configure(MapperFeature.DEFAULT_VIEW_INCLUSION, false); this.objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false); registerWellKnownModulesIfAvailable(); } public Jackson2JsonObjectMapper(ObjectMapper objectMapper) { Assert.notNull(objectMapper, "objectMapper must not be null"); this.objectMapper = objectMapper; } public ObjectMapper getObjectMapper() { return this.objectMapper; } @Override public String toJson(Object value) throws JsonProcessingException { return this.objectMapper.writeValueAsString(value); } @Override public void toJson(Object value, Writer writer) throws IOException { this.objectMapper.writeValue(writer, value); } @Override public JsonNode toJsonNode(Object json) throws IOException { try { if (json instanceof String) { return this.objectMapper.readTree((String) json); } else if (json instanceof byte[]) { return this.objectMapper.readTree((byte[]) json); } else if (json instanceof File) { return this.objectMapper.readTree((File) json); } else if (json instanceof URL) { return this.objectMapper.readTree((URL) json); } else if (json instanceof InputStream) { return this.objectMapper.readTree((InputStream) json); } else if (json instanceof Reader) { return this.objectMapper.readTree((Reader) json); } } catch (JsonParseException e) { if (!(json instanceof String) && !(json instanceof byte[])) { throw e; } // Otherwise the input might not be valid JSON, fallback to TextNode with ObjectMapper.valueToTree() } return this.objectMapper.valueToTree(json); } @Override protected <T> T fromJson(Object json, JavaType type) throws IOException { if (json instanceof String) { return this.objectMapper.readValue((String) json, type); } else if (json instanceof byte[]) { return this.objectMapper.readValue((byte[]) json, type); } else if (json instanceof File) { return this.objectMapper.readValue((File) json, type); } else if (json instanceof URL) { return this.objectMapper.readValue((URL) json, type); } else if (json instanceof InputStream) { return this.objectMapper.readValue((InputStream) json, type); } else if (json instanceof Reader) { return this.objectMapper.readValue((Reader) json, type); } else { throw new IllegalArgumentException("'json' argument must be an instance of: " + supportedJsonTypes + " , but gotten: " + json.getClass()); } } @Override public <T> T fromJson(JsonParser parser, Type valueType) throws IOException { return this.objectMapper.readValue(parser, constructType(valueType)); } @Override @SuppressWarnings({ "unchecked" }) protected JavaType extractJavaType(Map<String, Object> javaTypes) { JavaType classType = this.createJavaType(javaTypes, JsonHeaders.TYPE_ID); if (!classType.isContainerType() || classType.isArrayType()) { return classType; } JavaType contentClassType = this.createJavaType(javaTypes, JsonHeaders.CONTENT_TYPE_ID); if (classType.getKeyType() == null) { return this.objectMapper.getTypeFactory().constructCollectionType( (Class<? extends Collection<?>>) classType.getRawClass(), contentClassType); } JavaType keyClassType = createJavaType(javaTypes, JsonHeaders.KEY_TYPE_ID); return this.objectMapper.getTypeFactory().constructMapType( (Class<? extends Map<?, ?>>) classType.getRawClass(), keyClassType, contentClassType); } @Override protected JavaType constructType(Type type) { return this.objectMapper.constructType(type); } @SuppressWarnings("unchecked") private void registerWellKnownModulesIfAvailable() { try { Class<? extends Module> jdk7Module = (Class<? extends Module>) ClassUtils .forName("com.fasterxml.jackson.datatype.jdk7.Jdk7Module", getClassLoader()); this.objectMapper.registerModule(BeanUtils.instantiateClass(jdk7Module)); } catch (@SuppressWarnings(UNUSED) ClassNotFoundException ex) { // jackson-datatype-jdk7 not available } try { Class<? extends Module> jdk8Module = (Class<? extends Module>) ClassUtils .forName("com.fasterxml.jackson.datatype.jdk8.Jdk8Module", getClassLoader()); this.objectMapper.registerModule(BeanUtils.instantiateClass(jdk8Module)); } catch (@SuppressWarnings(UNUSED) ClassNotFoundException ex) { // jackson-datatype-jdk8 not available } try { Class<? extends Module> javaTimeModule = (Class<? extends Module>) ClassUtils .forName("com.fasterxml.jackson.datatype.jsr310.JavaTimeModule", getClassLoader()); this.objectMapper.registerModule(BeanUtils.instantiateClass(javaTimeModule)); } catch (@SuppressWarnings(UNUSED) ClassNotFoundException ex) { // jackson-datatype-jsr310 not available } // Joda-Time present? if (ClassUtils.isPresent("org.joda.time.LocalDate", getClassLoader())) { try { Class<? extends Module> jodaModule = (Class<? extends Module>) ClassUtils .forName("com.fasterxml.jackson.datatype.joda.JodaModule", getClassLoader()); this.objectMapper.registerModule(BeanUtils.instantiateClass(jodaModule)); } catch (@SuppressWarnings(UNUSED) ClassNotFoundException ex) { // jackson-datatype-joda not available } } // Kotlin present? if (ClassUtils.isPresent("kotlin.Unit", getClassLoader())) { try { Class<? extends Module> kotlinModule = (Class<? extends Module>) ClassUtils .forName("com.fasterxml.jackson.module.kotlin.KotlinModule", getClassLoader()); this.objectMapper.registerModule(BeanUtils.instantiateClass(kotlinModule)); } catch (@SuppressWarnings(UNUSED) ClassNotFoundException ex) { //jackson-module-kotlin not available } } } }