Java tutorial
/** This file is part of Waarp Project. Copyright 2009, Frederic Bregier, and individual contributors by the @author tags. See the COPYRIGHT.txt in the distribution for a full listing of individual contributors. All Waarp Project is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. Waarp is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Waarp . If not, see <http://www.gnu.org/licenses/>. */ package org.waarp.common.json; import java.io.IOException; import java.util.HashMap; import java.util.Map; import com.fasterxml.jackson.core.JsonGenerator; 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.JsonNode; import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.node.ArrayNode; import com.fasterxml.jackson.databind.node.ObjectNode; /** * Abstract Json Handler * * @author "Frederic Bregier" * */ public class JsonHandler { /** * JSON parser */ public static final ObjectMapper mapper = new ObjectMapper() .configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES, true) .configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true) .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false) .configure(JsonGenerator.Feature.ESCAPE_NON_ASCII, true); protected JsonHandler() { } /** * * @return an empty ObjectNode */ public static ObjectNode createObjectNode() { return mapper.createObjectNode(); } /** * * @return an empty ArrayNode */ public static ArrayNode createArrayNode() { return mapper.createArrayNode(); } /** * * @param value * @return the objectNode or null if an error occurs */ public static ObjectNode getFromString(String value) { try { return (ObjectNode) mapper.readTree(value); } catch (JsonProcessingException e) { return null; } catch (IOException e) { return null; } } /** * * @param object * @return the Json representation of the object */ public static String writeAsString(Object object) { try { return mapper.writeValueAsString(object); } catch (JsonProcessingException e) { return "{}"; } } /** * * @param object * @return the Json representation of the object in Pretty Print format */ public static String prettyPrint(Object object) { try { return mapper.writerWithDefaultPrettyPrinter().writeValueAsString(object); } catch (JsonProcessingException e) { return "{}"; } } /** * * @param node * @param field * @return the String if the field exists, else null */ public final static String getString(ObjectNode node, String field) { return getValue(node, field, (String) null); } /** * * @param node * @param field * @return the String if the field exists, else null */ public final static String getString(ObjectNode node, Enum<?> field) { return getValue(node, field.name(), (String) null); } /** * * @param node * @param field * @param defValue * @return the String if the field exists, else defValue */ public final static String getValue(ObjectNode node, String field, String defValue) { JsonNode elt = node.get(field); if (elt != null) { String val = elt.asText(); if (val.equals("null")) { return defValue; } return val; } return defValue; } /** * * @param node * @param field * @param defValue * @return the Boolean if the field exists, else defValue */ public final static Boolean getValue(ObjectNode node, String field, boolean defValue) { return node.path(field).asBoolean(defValue); } /** * * @param node * @param field * @param defValue * @return the Double if the field exists, else defValue */ public final static Double getValue(ObjectNode node, String field, double defValue) { return node.path(field).asDouble(defValue); } /** * * @param node * @param field * @param defValue * @return the Long if the field exists, else defValue */ public final static Long getValue(ObjectNode node, String field, long defValue) { return node.path(field).asLong(defValue); } /** * * @param node * @param field * @param defValue * @return the Integer if the field exists, else defValue */ public final static Integer getValue(ObjectNode node, String field, int defValue) { return node.path(field).asInt(defValue); } /** * * @param node * @param field * @param defValue * @return the byte array if the field exists, else defValue */ public final static byte[] getValue(ObjectNode node, String field, byte[] defValue) { JsonNode elt = node.get(field); if (elt != null) { try { return elt.binaryValue(); } catch (IOException e) { return defValue; } } return defValue; } /** * * @param node * @param field * @param value */ public final static void setValue(ObjectNode node, String field, boolean value) { node.put(field, value); } /** * * @param node * @param field * @param value */ public final static void setValue(ObjectNode node, String field, double value) { node.put(field, value); } /** * * @param node * @param field * @param value */ public final static void setValue(ObjectNode node, String field, int value) { node.put(field, value); } /** * * @param node * @param field * @param value */ public final static void setValue(ObjectNode node, String field, long value) { node.put(field, value); } /** * * @param node * @param field * @param value */ public final static void setValue(ObjectNode node, String field, String value) { if (value == null || value.isEmpty()) { return; } node.put(field, value); } /** * * @param node * @param field * @param value */ public final static void setValue(ObjectNode node, String field, byte[] value) { if (value == null || value.length == 0) { return; } node.put(field, value); } /** * * @param node * @param field * @return True if all fields exist */ public final static boolean exist(ObjectNode node, String... field) { for (String string : field) { if (!node.has(string)) return false; } return true; } /** * * @param node * @param field * @param defValue * @return the String if the field exists, else defValue */ public final static String getValue(ObjectNode node, Enum<?> field, String defValue) { return getValue(node, field.name(), defValue); } /** * * @param node * @param field * @param defValue * @return the Boolean if the field exists, else defValue */ public final static Boolean getValue(ObjectNode node, Enum<?> field, boolean defValue) { return node.path(field.name()).asBoolean(defValue); } /** * * @param node * @param field * @param defValue * @return the Double if the field exists, else defValue */ public final static Double getValue(ObjectNode node, Enum<?> field, double defValue) { return node.path(field.name()).asDouble(defValue); } /** * * @param node * @param field * @param defValue * @return the Long if the field exists, else defValue */ public final static Long getValue(ObjectNode node, Enum<?> field, long defValue) { return node.path(field.name()).asLong(defValue); } /** * * @param node * @param field * @param defValue * @return the Integer if the field exists, else defValue */ public final static Integer getValue(ObjectNode node, Enum<?> field, int defValue) { return node.path(field.name()).asInt(defValue); } /** * * @param node * @param field * @param defValue * @return the byte array if the field exists, else defValue */ public final static byte[] getValue(ObjectNode node, Enum<?> field, byte[] defValue) { return getValue(node, field.name(), defValue); } /** * * @param node * @param field * @param value */ public final static void setValue(ObjectNode node, Enum<?> field, boolean value) { node.put(field.name(), value); } /** * * @param node * @param field * @param value */ public final static void setValue(ObjectNode node, Enum<?> field, double value) { node.put(field.name(), value); } /** * * @param node * @param field * @param value */ public final static void setValue(ObjectNode node, Enum<?> field, int value) { node.put(field.name(), value); } /** * * @param node * @param field * @param value */ public final static void setValue(ObjectNode node, Enum<?> field, long value) { node.put(field.name(), value); } /** * * @param node * @param field * @param value */ public final static void setValue(ObjectNode node, Enum<?> field, String value) { if (value == null || value.isEmpty()) { return; } node.put(field.name(), value); } /** * * @param node * @param field * @param value */ public final static void setValue(ObjectNode node, Enum<?> field, byte[] value) { if (value == null || value.length == 0) { return; } node.put(field.name(), value); } /** * * @param node * @param field * @return True if all fields exist */ public final static boolean exist(ObjectNode node, Enum<?>... field) { for (Enum<?> enm : field) { if (!node.has(enm.name())) return false; } return true; } /** * * @param value * @return the corresponding HashMap */ public static Map<String, Object> getMapFromString(String value) { if (value != null && !value.isEmpty()) { Map<String, Object> info = null; try { info = mapper.readValue(value, new TypeReference<Map<String, Object>>() { }); } catch (JsonParseException e1) { } catch (JsonMappingException e1) { } catch (IOException e1) { } if (info == null) { info = new HashMap<String, Object>(); } return info; } else { return new HashMap<String, Object>(); } } }