org.nebula.service.util.JsonUtils.java Source code

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Here is the source code for org.nebula.service.util.JsonUtils.java

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/*
 * Copyright 2002-2015 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
 *
 *      http://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.nebula.service.util;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.type.CollectionType;

import org.apache.log4j.Logger;

import java.util.List;
import java.util.Map;

public class JsonUtils {

    private final static Logger logger = Logger.getLogger(JsonUtils.class);

    private final static ObjectMapper mapper = new ObjectMapper();

    public final static String toJson(Object obj) {
        try {
            return mapper.writeValueAsString(obj);
        } catch (Exception e) {
            logger.error("Failed to convert the object " + obj + " to json.");
        }
        return "";
    }

    public final static Object toObject(String json, String className) {
        try {
            return mapper.readValue(json, Class.forName(className));
        } catch (Exception e) {
            logger.error("Failed to convert the json " + json + " to object " + className);
        }
        return "";
    }

    public final static <T> T toObject(String json, Class<T> clazz) {
        try {
            return mapper.readValue(json, clazz);
        } catch (Exception e) {
            logger.error("Failed to convert the json " + json + " to object " + clazz, e);
        }
        return null;
    }

    public final static List toList(String json, Class clazz) {
        try {
            final CollectionType javaType = mapper.getTypeFactory().constructCollectionType(List.class, clazz);
            return mapper.readValue(json, javaType);
        } catch (Exception e) {
            logger.error("Failed to convert the json " + json + " to " + clazz.getName() + " list");
        }
        return null;
    }

    public final static Map toMap(String json) {
        try {
            return mapper.readValue(json, new TypeReference<Map<String, Object>>() {
            });
        } catch (Exception e) {
            logger.error("Failed to convert the json " + json + " to map");
        }
        return null;
    }
}