util.JsonMapper.java Source code

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Here is the source code for util.JsonMapper.java

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/*******************************************************************************
 * Copyright (c) 2005, 2014 springside.github.io
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 *******************************************************************************/
package util;

import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.util.JSONPObject;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.text.ParseException;
import java.util.Collection;
import java.util.Date;
import java.util.Map;

/**
 * ??JacksonJSON String<->Java Object?Mapper.
 * <p>
 * ?JsonMapper.INSTANCE, ???builder???,
 * <p>
 * ??GSON, ??.
 * <p>
 * ?: ???POM?jackson.
 *
 * @author calvin
 */
public class JsonMapper {

    private static Logger logger = LoggerFactory.getLogger(JsonMapper.class);

    public static final JsonMapper INSTANCE = new JsonMapper();
    private static String SIMPLE_FORMAT = "yyyy-MM-dd HH:mm:ss";

    private ObjectMapper mapper;

    public JsonMapper() {
        this(null);
    }

    public JsonMapper(Include include) {
        mapper = new ObjectMapper();
        // ?
        if (include != null) {
            mapper.setSerializationInclusion(include);
        }

        SimpleModule javaTimeModule = new SimpleModule();
        //        javaTimeModule.addSerializer(Date.class, new JsonDateSerializer());
        //        javaTimeModule.addDeserializer(Date.class, new JsonDateDeserializer());
        //        mapper.registerModule(javaTimeModule);
        // JSONJava
        mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
    }

    /**
     * ??NullJsonMapper.
     */
    public static JsonMapper nonNullMapper() {
        return new JsonMapper(Include.NON_NULL);
    }

    /**
     * ??Null?Empty(List.isEmpty)JsonMapper.
     * <p>
     * ???, ?empty.
     */
    public static JsonMapper nonEmptyMapper() {
        return new JsonMapper(Include.NON_EMPTY);
    }

    /**
     * Mapper, INSTANCE???
     */
    public static JsonMapper defaultMapper() {
        return new JsonMapper();
    }

    /**
     * Object?POJO?Collection Null, "null". ??, "[]".
     */
    public String toJson(Object object) {

        try {
            return mapper.writeValueAsString(object);
        } catch (IOException e) {
            logger.warn("write to json string error:" + object, e);
            return null;
        }
    }

    public String toPrettyJson(Object object) {

        try {
            return mapper.writerWithDefaultPrettyPrinter().writeValueAsString(object);
        } catch (IOException e) {
            logger.warn("write to json string error:" + object, e);
            return null;
        }
    }

    /**
     * ???POJO?CollectionList<String>.
     * <p>
     * JSONNull"null", Null. JSON"[]", ?.
     * <p>
     * ?????CollectionList<MyBean>, fromJson(String, JavaType)
     *
     * @see #fromJson(String, JavaType)
     */
    public <T> T fromJson(String jsonString, Class<T> clazz) {
        if (StringUtils.isEmpty(jsonString)) {
            return null;
        }

        try {
            return mapper.readValue(jsonString, clazz);
        } catch (IOException e) {
            logger.warn("parse json string error:" + jsonString, e);
            return null;
        }
    }

    /**
     * ?????CollectionList<Bean>, contructCollectionType()contructMapType(), ?.
     */
    public <T> T fromJson(String jsonString, JavaType javaType) {
        if (StringUtils.isEmpty(jsonString)) {
            return null;
        }

        try {
            return (T) mapper.readValue(jsonString, javaType);
        } catch (IOException e) {
            logger.warn("parse json string error:" + jsonString, e);
            return null;
        }
    }

    /**
     * Collection.
     */
    public JavaType buildCollectionType(Class<? extends Collection> collectionClass, Class<?> elementClass) {
        return mapper.getTypeFactory().constructCollectionType(collectionClass, elementClass);
    }

    /**
     * Map.
     */
    public JavaType buildMapType(Class<? extends Map> mapClass, Class<?> keyClass, Class<?> valueClass) {
        return mapper.getTypeFactory().constructMapType(mapClass, keyClass, valueClass);
    }

    /**
     * JSON??BeanBean?.
     */
    public void update(String jsonString, Object object) {
        try {
            mapper.readerForUpdating(object).readValue(jsonString);
        } catch (JsonProcessingException e) {
            logger.warn("update json string:" + jsonString + " to object:" + object + " error.", e);
        } catch (IOException e) {
            logger.warn("update json string:" + jsonString + " to object:" + object + " error.", e);
        }
    }

    /**
     * JSONP?.
     */
    public String toJsonP(String functionName, Object object) {
        return toJson(new JSONPObject(functionName, object));
    }

    /**
     * ?EnumtoStringEnum, FalseEnumname()Enum, ?False. ??Mapper, ?.
     */
    public void enableEnumUseToString() {
        mapper.enable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
        mapper.enable(DeserializationFeature.READ_ENUMS_USING_TO_STRING);
    }

    /**
     * ?Mapper??API.
     */
    public ObjectMapper getMapper() {
        return mapper;
    }

    /**
     * Date?
     */
    public static class JsonDateSerializer extends JsonSerializer<Date> {

        @Override
        public void serialize(Date date, JsonGenerator gen, SerializerProvider serializers)
                throws IOException, JsonProcessingException {
            String formattedDate = DateFormatUtils.formatDate(SIMPLE_FORMAT, date);
            gen.writeString(formattedDate);
        }
    }

    /**
     * Date???
     */
    public static class JsonDateDeserializer extends JsonDeserializer<Date> {
        @Override
        public Date deserialize(JsonParser jp, DeserializationContext ctxt)
                throws IOException, JsonProcessingException {
            if (StringUtils.isEmpty(jp.getText())) {
                return null;
            }
            try {
                return DateFormatUtils.pareDate(SIMPLE_FORMAT, jp.getText());
            } catch (ParseException e) {
                e.printStackTrace();
                throw new IOException(e.getMessage());
            }

        }
    }

}