Java tutorial
/* * Copyright (c) 2011-2019 Contributors to the Eclipse Foundation * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License 2.0 which is available at * http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0 * which is available at https://www.apache.org/licenses/LICENSE-2.0. * * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 */ package io.vertx.core.json; import io.vertx.core.ServiceHelper; import io.vertx.core.buffer.Buffer; import io.vertx.core.json.jackson.JacksonFactory; import io.vertx.core.spi.JsonFactory; import io.vertx.core.spi.json.JsonCodec; /** * @author <a href="http://tfox.org">Tim Fox</a> */ public class Json { /** * */ public static final JsonCodec CODEC = JsonFactory.INSTANCE.codec(); /** * Load the factory with the {@code ServiceLoader}, when no factory is found then a factory * using Jackson will be returned. * <br/> * When {@code jackson-databind} is available then a codec using it will be used otherwise * the codec will only use {@code jackson-core} and provide best effort mapping. */ public static io.vertx.core.spi.JsonFactory load() { io.vertx.core.spi.JsonFactory factory = ServiceHelper .loadFactoryOrNull(io.vertx.core.spi.JsonFactory.class); if (factory == null) { factory = JacksonFactory.INSTANCE; } return factory; } /** * Encode a POJO to JSON using the underlying Jackson mapper. * * @param obj a POJO * @return a String containing the JSON representation of the given POJO. * @throws EncodeException if a property cannot be encoded. */ public static String encode(Object obj) throws EncodeException { return CODEC.toString(obj); } /** * Encode a POJO to JSON using the underlying Jackson mapper. * * @param obj a POJO * @return a Buffer containing the JSON representation of the given POJO. * @throws EncodeException if a property cannot be encoded. */ public static Buffer encodeToBuffer(Object obj) throws EncodeException { return CODEC.toBuffer(obj); } /** * Encode a POJO to JSON with pretty indentation, using the underlying Jackson mapper. * * @param obj a POJO * @return a String containing the JSON representation of the given POJO. * @throws EncodeException if a property cannot be encoded. */ public static String encodePrettily(Object obj) throws EncodeException { return CODEC.toString(obj, true); } /** * Decode a given JSON string to a POJO of the given class type. * @param str the JSON string. * @param clazz the class to map to. * @param <T> the generic type. * @return an instance of T * @throws DecodeException when there is a parsing or invalid mapping. */ public static <T> T decodeValue(String str, Class<T> clazz) throws DecodeException { return CODEC.fromString(str, clazz); } /** * Decode a given JSON string. * * @param str the JSON string. * * @return a JSON element which can be a {@link JsonArray}, {@link JsonObject}, {@link String}, ...etc if the content is an array, object, string, ...etc * @throws DecodeException when there is a parsing or invalid mapping. */ public static Object decodeValue(String str) throws DecodeException { return decodeValue(str, Object.class); } /** * Decode a given JSON buffer. * * @param buf the JSON buffer. * * @return a JSON element which can be a {@link JsonArray}, {@link JsonObject}, {@link String}, ...etc if the buffer contains an array, object, string, ...etc * @throws DecodeException when there is a parsing or invalid mapping. */ public static Object decodeValue(Buffer buf) throws DecodeException { return decodeValue(buf, Object.class); } /** * Decode a given JSON buffer to a POJO of the given class type. * @param buf the JSON buffer. * @param clazz the class to map to. * @param <T> the generic type. * @return an instance of T * @throws DecodeException when there is a parsing or invalid mapping. */ public static <T> T decodeValue(Buffer buf, Class<T> clazz) throws DecodeException { return CODEC.fromBuffer(buf, clazz); } }