com.rockagen.commons.util.JsonUtil.java Source code

Introduction

Here is the source code for com.rockagen.commons.util.JsonUtil.java

Source

/*
 * Copyright 2014 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 com.rockagen.commons.util;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.StringWriter;
import java.net.URL;
import java.text.DateFormat;
import java.text.SimpleDateFormat;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;

/**
 * JSON UTILS
 * 
 * @author RA
 * @since JDK1.6
 * @since JACKSON 2.2.0
 */
public class JsonUtil {

    // ~ Instance fields ==================================================

    /**
     * 
     */
    private static final Logger log = LoggerFactory.getLogger(JsonUtil.class);
    /**
     * ObjectMapper
     */
    private static final ThreadLocal<ObjectMapper> threadMapper = new ThreadLocal<ObjectMapper>();
    /**
     * JsonFactory
     */
    private static final ThreadLocal<JsonFactory> threadJsonFactory = new ThreadLocal<JsonFactory>();

    // ~ Constructors ==================================================

    /**
     */
    private JsonUtil() {

    }

    // ~ Methods ==================================================

    /**
     * return a ObjectMapper if exist,else new ObjectMapper
     * 
     * @return ObjectMapper
     */
    public static ObjectMapper getMapper() {

        ObjectMapper mapper = threadMapper.get();
        if (mapper == null) {
            mapper = initMapper();
            threadMapper.set(mapper);

        }
        return mapper;
    }

    /**
     * Initialize mapper
     * 
     * @return initialized {@link ObjectMapper}
     */
    private static ObjectMapper initMapper() {

        ObjectMapper mapper = new ObjectMapper();
        // to enable standard indentation ("pretty-printing"):
        mapper.enable(SerializationFeature.INDENT_OUTPUT);
        // to allow serialization of "empty" POJOs (no properties to serialize)
        // (without this setting, an exception is thrown in those cases)
        mapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);
        // set writer flush after writer value
        mapper.enable(SerializationFeature.FLUSH_AFTER_WRITE_VALUE);
        // ObjectMapper will call close() and root values that implement
        // java.io.Closeable;
        // including cases where exception is thrown and serialization does not
        // completely succeed.
        mapper.enable(SerializationFeature.CLOSE_CLOSEABLE);
        // to write java.util.Date, Calendar as number (timestamp):
        mapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
        // disable default date to timestamp
        mapper.disable(SerializationFeature.WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS);

        // DeserializationFeature for changing how JSON is read as POJOs:

        // to prevent exception when encountering unknown property:
        mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
        // disable default date to timestamp
        mapper.disable(DeserializationFeature.READ_DATE_TIMESTAMPS_AS_NANOSECONDS);
        // to allow coercion of JSON empty String ("") to null Object value:
        mapper.enable(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT);
        DateFormat df = new SimpleDateFormat("yyyyMMddHHmmssSSS");
        // Set Default date fromat
        mapper.setDateFormat(df);

        return mapper;

    }

    /**
     * return a JsonFactory if exist,else new JsonFactory
     * 
     * @return JsonFactory
     */
    public static JsonFactory getJsonFactory() {

        JsonFactory jsonFactory = threadJsonFactory.get();
        if (jsonFactory == null) {
            jsonFactory = new JsonFactory();
            // JsonParser.Feature for configuring parsing settings:
            // to allow C/C++ style comments in JSON (non-standard, disabled by
            // default)
            jsonFactory.enable(JsonParser.Feature.ALLOW_COMMENTS);
            // to allow (non-standard) unquoted field names in JSON:
            jsonFactory.disable(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES);
            // to allow use of apostrophes (single quotes), non standard
            jsonFactory.disable(JsonParser.Feature.ALLOW_SINGLE_QUOTES);

            // JsonGenerator.Feature for configuring low-level JSON generation:

            // no escaping of non-ASCII characters:
            jsonFactory.disable(JsonGenerator.Feature.ESCAPE_NON_ASCII);
            threadJsonFactory.set(jsonFactory);

        }
        return jsonFactory;
    }

    /**
     * Json string to java bean <br>
     * <p>
     * List,Array,Map
     * </p>
     * <pre>
     * clazz= new TypeReference&lt;List&lt;MyBean&gt;&gt;(){};
     * 
     * e.g:
     * toBean(jsonStr,new TypeReference&lt;List&lt;MyBean&gt;&gt;(){})
     * 
     * toBean(jsonStr, MyBean[])
     * 
     * toBean(jsonStr, new TypeReference&lt;Map&lt;String, Map&lt;String, MyBean&gt;&gt;(){})
     * </pre>
     * 
     * @param jsonStr json String
     * @param valueTypeRef value type ref
     * @param <T> t    
     * @return bean
     */
    public static <T> T toBean(String jsonStr, TypeReference<T> valueTypeRef) {
        if (valueTypeRef == null || jsonStr == null)
            return null;
        return toBean(new MyJsonParser(jsonStr), valueTypeRef);

    }

    /**
     * Json string to java bean <br>
     * <p>
     * List,Array,Map
     * </p>
     * <pre>
     * clazz= new TypeReference&lt;List&lt;MyBean&gt;&gt;(){};
     * 
     * e.g:
     * toBean(jsonBytes,new TypeReference&lt;List&lt;MyBean&gt;&gt;(){})
     * 
     * toBean(jsonBytes, MyBean[])
     * 
     * toBean(jsonBytes, new TypeReference&lt;Map&lt;String, Map&lt;String, MyBean&gt;&gt;(){})
     * </pre>
     * 
     * @param jsonBytes json bytes
     * @param valueTypeRef value type ref
     * @param <T> t                         
     * @return bean
     */
    public static <T> T toBean(byte[] jsonBytes, TypeReference<T> valueTypeRef) {
        if (valueTypeRef == null || jsonBytes == null)
            return null;
        return toBean(new MyJsonParser(jsonBytes), valueTypeRef);

    }

    /**
     * Json string to java bean <br>
     * <p>
     * List,Array,Map
     * </p>
     * <pre>
     * clazz= new TypeReference&lt;List&lt;MyBean&gt;&gt;(){};
     * 
     * e.g:
     * toBean(jsonReader,new TypeReference&lt;List&lt;MyBean&gt;&gt;(){})
     * 
     * toBean(jsonReader, MyBean[])
     * 
     * toBean(jsonReader, new TypeReference&lt;Map&lt;String, Map&lt;String, MyBean&gt;&gt;(){})
     * </pre>
     * 
     * @param jsonReader json reader
     * @param valueTypeRef value type ref
     * @param <T> t                         
     * @return bean
     */
    public static <T> T toBean(Reader jsonReader, TypeReference<T> valueTypeRef) {
        if (valueTypeRef == null || jsonReader == null)
            return null;
        return toBean(new MyJsonParser(jsonReader), valueTypeRef);

    }

    /**
     * Json string to java bean <br>
     * <p>
     * List,Array,Map
     * </p>
     * <pre>
     * clazz= new TypeReference&lt;List&lt;MyBean&gt;&gt;(){};
     * 
     * e.g:
     * toBean(jsonURL,new TypeReference&lt;List&lt;MyBean&gt;&gt;(){})
     * 
     * toBean(jsonURL, MyBean[])
     * 
     * toBean(jsonURL, new TypeReference&lt;Map&lt;String, Map&lt;String, MyBean&gt;&gt;(){})
     * </pre>
     * 
     * @param jsonURL json url
     * @param valueTypeRef value type ref
     * @param <T> t                         
     * @return bean
     */
    public static <T> T toBean(URL jsonURL, TypeReference<T> valueTypeRef) {
        if (valueTypeRef == null || jsonURL == null)
            return null;
        return toBean(new MyJsonParser(jsonURL), valueTypeRef);

    }

    /**
     * Json string to java bean <br>
     * <p>
     * List,Array,Map
     * </p>
     * <pre>
     * clazz= new TypeReference&lt;List&lt;MyBean&gt;&gt;(){};
     * 
     * e.g:
     * toBean(jsonFile,new TypeReference&lt;List&lt;MyBean&gt;&gt;(){})
     * 
     * toBean(jsonFile, MyBean[])
     * 
     * toBean(jsonFile, new TypeReference&lt;Map&lt;String, Map&lt;String, MyBean&gt;&gt;(){})
     * </pre>
     * 
     * @param jsonFile josn file
     * @param valueTypeRef value type ref
     * @param <T> t                        
     * @return bean
     */
    public static <T> T toBean(File jsonFile, TypeReference<T> valueTypeRef) {
        if (valueTypeRef == null || jsonFile == null)
            return null;
        return toBean(new MyJsonParser(jsonFile), valueTypeRef);

    }

    /**
     * Json string to java bean <br>
     * <p>
     * call {@link MyJsonParser#getJsonParser()} return a JsonParser
     * </p>
     * 
     * @param myJsonParser custom json parser
     * @param valueTypeRef value type ref
     * @see #toBean(JsonParser, TypeReference)
     * @param <T> t  
     * @return bean
     */
    protected static <T> T toBean(MyJsonParser myJsonParser, TypeReference<T> valueTypeRef) {
        if (myJsonParser.getJsonParser() == null)
            return null;
        return toBean(myJsonParser.getJsonParser(), valueTypeRef);
    }

    /**
     * Json string to java bean <br>
     * <p>
     * List,Array,Map
     * </p>
     * <pre>
     * clazz= new TypeReference&lt;List&lt;MyBean&gt;&gt;(){};
     * 
     * e.g:
     * toBean(jsonParser,new TypeReference&lt;List&lt;MyBean&gt;&gt;(){})
     * 
     * toBean(jsonParser, MyBean[])
     * 
     * toBean(jsonParser, new TypeReference&lt;Map&lt;String, Map&lt;String, MyBean&gt;&gt;(){})
     * </pre>
     * 
     * @param jsonParser json parser
     * @param valueTypeRef value type ref
     * @param <T> t                         
     * @return bean
     */
    public static <T> T toBean(JsonParser jsonParser, TypeReference<T> valueTypeRef) {
        if (valueTypeRef == null || jsonParser == null)
            return null;

        T obj = null;
        try {
            obj = getMapper().readValue(jsonParser, valueTypeRef);
        } catch (JsonParseException e) {
            log.error("{}", e.getMessage(), e);
        } catch (JsonMappingException e) {
            log.error("{}", e.getMessage(), e);
        } catch (IOException e) {
            log.error("{}", e.getMessage(), e);
        } finally {
            try {
                jsonParser.close();
            } catch (IOException e) {
            }
        }
        return obj;
    }

    /**
     * Json string to java bean <br>
     * <p>
     * e.g:
     * </p>
     * <pre>
     * {"id" : idValue, "name" : nameValue, "aBean" : {"aBeanId" : aBeanIdValue, ...}} 
     * </pre>
     * <p>
     * List,Array,Map... see {@link #toBean(String, TypeReference)}
     * </p>
     * 
     * @param jsonStr json String
     * @param clazz class
     * @param <T> t                  
     * @return bean
     */
    public static <T> T toBean(String jsonStr, Class<T> clazz) {
        if (clazz == null || jsonStr == null)
            return null;
        return toBean(new MyJsonParser(jsonStr), clazz);

    }

    /**
     * Json string to java bean <br>
     * <p>
     * e.g:
     * </p>
     * <pre>
     * {"id" : idValue, "name" : nameValue, "aBean" : {"aBeanId" : aBeanIdValue, ...}} 
     * </pre>
     * <p>
     * List,Array,Map... see {@link #toBean(byte[], TypeReference)}
     * </p>
     * 
     * @param jsonBytes josn bytes
     * @param clazz class
     * @param <T> t                  
     * @return bean
     */
    public static <T> T toBean(byte[] jsonBytes, Class<T> clazz) {
        if (clazz == null || jsonBytes == null)
            return null;
        return toBean(new MyJsonParser(jsonBytes), clazz);

    }

    /**
     * Json string to java bean <br>
     * <p>
     * e.g:
     * </p>
     * <pre>
     * {"id" : idValue, "name" : nameValue, "aBean" : {"aBeanId" : aBeanIdValue, ...}} 
     * </pre>
     * <p>
     * List,Array,Map... see {@link #toBean(Reader, TypeReference)}
     * </p>
     * 
     * @param jsonReader json reader
     * @param clazz class
     * @param <T> t
     * @return bean
     */
    public static <T> T toBean(Reader jsonReader, Class<T> clazz) {
        if (clazz == null || jsonReader == null)
            return null;
        return toBean(new MyJsonParser(jsonReader), clazz);

    }

    /**
     * Json string to java bean <br>
     * <p>
     * e.g:
     * </p>
     * <pre>
     * {"id" : idValue, "name" : nameValue, "aBean" : {"aBeanId" : aBeanIdValue, ...}} 
     * </pre>
     * <p>
     * List,Array,Map... see {@link #toBean(URL, TypeReference)}
     * </p>
     * 
     * @param jsonURL josn url
     * @param clazz class
     * @param <T> t                 
     * @return bean
     */
    public static <T> T toBean(URL jsonURL, Class<T> clazz) {
        if (clazz == null || jsonURL == null)
            return null;
        return toBean(new MyJsonParser(jsonURL), clazz);

    }

    /**
     * Json string to java bean <br>
     * <p>
     * e.g:
     * </p>
     * <pre>
     * {"id" : idValue, "name" : nameValue, "aBean" : {"aBeanId" : aBeanIdValue, ...}} 
     * </pre>
     * <p>
     * List,Array,Map... see {@link #toBean(File, TypeReference)}
     * </p>
     * 
     * @param jsonFile json file
     * @param clazz class
     * @param <T> t                  
     * @return bean
     */
    public static <T> T toBean(File jsonFile, Class<T> clazz) {
        if (clazz == null || jsonFile == null)
            return null;
        return toBean(new MyJsonParser(jsonFile), clazz);

    }

    /**
     * Json string to java bean <br>
     * <p>
     * call {@link MyJsonParser#getJsonParser()} return a JsonParser
     * </p>
     * 
     * @param myJsonParser custom json parser
     * @param clazz class
     * @see #toBean(JsonParser, Class)
     * @param <T> t  
     * @return bean
     */
    protected static <T> T toBean(MyJsonParser myJsonParser, Class<T> clazz) {
        if (myJsonParser.getJsonParser() == null)
            return null;
        return toBean(myJsonParser.getJsonParser(), clazz);
    }

    /**
     * Json string to java bean <br>
     * <p>
     * e.g:
     * </p>
     * <pre>
     * {"id" : idValue, "name" : nameValue, "aBean" : {"aBeanId" : aBeanIdValue, ...}} 
     * </pre>
     * <p>
     * List,Array,Map... see {@link #toBean(String, TypeReference)}
     * </p>
     * 
     * @param jsonParser json parser
     * @param clazz class
     * @param <T> t
     * @return bean
     */
    public static <T> T toBean(JsonParser jsonParser, Class<T> clazz) {
        if (clazz == null || jsonParser == null)
            return null;

        T obj = null;
        try {
            obj = getMapper().readValue(jsonParser, clazz);
        } catch (JsonParseException e) {
            log.error("{}", e.getMessage(), e);
        } catch (JsonMappingException e) {
            log.error("{}", e.getMessage(), e);
        } catch (IOException e) {
            log.error("{}", e.getMessage(), e);
        } finally {
            try {
                jsonParser.close();
            } catch (IOException e) {
            }
        }
        return obj;

    }

    /**
     * Bean to json string
     * 
     * @param obj obj
     *            bean object
     * @param <T> t           
     * @return json string
     */
    public static <T> String toJson(T obj) {
        StringWriter writer = new StringWriter();
        String jsonStr = "";
        JsonGenerator gen = null;
        try {
            gen = getJsonFactory().createGenerator(writer);
            getMapper().writeValue(gen, obj);
            writer.flush();
            jsonStr = writer.toString();

        } catch (IOException e) {
            log.error("{}", e.getMessage(), e);
        } finally {
            if (gen != null) {
                try {
                    gen.close();
                } catch (IOException e) {
                }
            }

        }
        return jsonStr;
    }

    /**
     * JsonParser Helper<br> provide to
     * {@link JsonUtil#toBean(MyJsonParser, Class)} and
     * {@link JsonUtil#toBean(MyJsonParser, TypeReference)}
     */
    protected static class MyJsonParser {

        // ~ Instance fields ==================================================

        /**
         * JsonParser
         */
        private JsonParser jsonParser;

        // ~ Constructors ==================================================

        /**
         * Set jsonParser from {@link JsonFactory#createParser(File)}
         * 
         * @param obj obj
         */
        public MyJsonParser(File obj) {
            try {
                this.jsonParser = getJsonFactory().createParser(obj);
            } catch (JsonParseException e) {
                log.error("{}", e.getMessage(), e);
            } catch (IOException e) {
                log.error("{}", e.getMessage(), e);
            }
        }

        /**
         * Set jsonParser from {@link JsonFactory#createParser(Reader)}
         * 
         * @param obj obj
         */
        public MyJsonParser(Reader obj) {
            try {
                this.jsonParser = getJsonFactory().createParser(obj);
            } catch (JsonParseException e) {
                log.error("{}", e.getMessage(), e);
            } catch (IOException e) {
                log.error("{}", e.getMessage(), e);
            }
        }

        /**
         * Set jsonParser from {@link JsonFactory#createParser(byte[])}
         * 
         * @param obj obj
         */
        public MyJsonParser(byte[] obj) {
            try {
                this.jsonParser = getJsonFactory().createParser(obj);
            } catch (JsonParseException e) {
                log.error("{}", e.getMessage(), e);
            } catch (IOException e) {
                log.error("{}", e.getMessage(), e);
            }
        }

        /**
         * Set jsonParser from {@link JsonFactory#createParser(String)}
         * 
         * @param obj obj
         */
        public MyJsonParser(String obj) {
            try {
                this.jsonParser = getJsonFactory().createParser(obj);
            } catch (JsonParseException e) {
                log.error("{}", e.getMessage(), e);
            } catch (IOException e) {
                log.error("{}", e.getMessage(), e);
            }
        }

        /**
         * Set jsonParser from {@link JsonFactory#createParser(URL)}
         * 
         * @param obj obj
         */
        public MyJsonParser(URL obj) {
            try {
                this.jsonParser = getJsonFactory().createParser(obj);
            } catch (JsonParseException e) {
                log.error("{}", e.getMessage(), e);
            } catch (IOException e) {
                log.error("{}", e.getMessage(), e);
            }
        }

        /**
         * Set jsonParser from {@link JsonFactory#createParser(InputStream)}
         * 
         * @param obj obj
         */
        public MyJsonParser(InputStream obj) {
            try {
                this.jsonParser = getJsonFactory().createParser(obj);
            } catch (JsonParseException e) {
                log.error("{}", e.getMessage(), e);
            } catch (IOException e) {
                log.error("{}", e.getMessage(), e);
            }
        }

        // ~ Methods ==================================================

        /**
         * Return a JsonParser by Constructors
         * 
         * @return jsonParser
         */
        public JsonParser getJsonParser() {
            return jsonParser;
        }

    }

}