package com.dominos.cloud.common.util;

import java.io.IOException;

import java.text.DateFormat;

import java.text.SimpleDateFormat;

import java.util.Collection;

import java.util.HashMap;

import java.util.Map;

import org.apache.commons.lang.StringUtils;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.annotation.JsonInclude.Include;

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.ObjectMapper;

import com.fasterxml.jackson.databind.ObjectMapper.DefaultTyping;

import com.fasterxml.jackson.databind.SerializationFeature;

import com.fasterxml.jackson.databind.type.CollectionType;

import com.fasterxml.jackson.databind.util.JSONPObject;

/**

* Json工具转换类

*

*/

public class JsonUtils {

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

private static ObjectMapper mapper = null;

private static ObjectMapper mapperWithType = null;

static {

mapper = new ObjectMapper();

// 设置输入时忽略在JSON字符串中存在但Java对象实际没有的属性

mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);

// 允许key没有使用双引号的json

mapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);

// 零时区

DateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

mapper.setDateFormat(format);

// 驼峰转换

//mapper.setPropertyNamingStrategy(PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES);

// 多态转换

//mapper.enableDefaultTyping(DefaultTyping.NON_FINAL);

//配置不写value为null的key

mapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);

// 输出格式化

mapper.configure(SerializationFeature.INDENT_OUTPUT, false);

mapper.setSerializationInclusion(Include.NON_NULL);

mapperWithType = new ObjectMapper();

mapperWithType.enableDefaultTyping(DefaultTyping.NON_FINAL);

}

/**

* 将对象转换成JSON字符串

*

* @param obj

* 目标对象

* @return 字符串，转换失败时返回null

*/

public static String toJson(Object obj) {

try {

return mapper.writeValueAsString(obj);

} catch (JsonProcessingException e) {

logger.error("write to json string error:" + obj, e);

return null;

}

}

/**

* 将单个键值对转换成JSON字符串，用于返回只有一个键值对json时的便捷方法

*

* @return 字符串，转换失败时返回null

*/

public static String toJson(Object key, Object value) {

Map map = new HashMap();

map.put(key, value);

try {

return mapper.writeValueAsString(map);

} catch (JsonProcessingException e) {

logger.error("write to json string error:" + map, e);

return null;

}

}

/**

* 反序列化POJO或简单Collection如List.

*

* 如果JSON字符串为Null或"null"字符串, 返回Null. 如果JSON字符串为"[]", 返回空集合.

*

* 如需反序列化复杂Collection如List, 请使用fromJson(String, JavaType)

*

*/

public static T fromJson(String jsonString, Class clazz) {

if (StringUtils.isBlank(jsonString)) {

return null;

}

try {

return mapper.readValue(jsonString, clazz);

} catch (IOException e) {

logger.error("parse json string error:" + jsonString, e);

return null;

}

}

/**

* 反序列化复杂Collection如List

*

* @param jsonString

* @param collectionType

* 集合类型

* @param elementType

* 集合内元素类型

* @return 转换失败时返回 null

*/

public static , E> L fromJson(String jsonString,

Class collectionClass, Class elementClass) {

if (StringUtils.isBlank(jsonString)) {

return null;

}

try {

CollectionType type = mapper.getTypeFactory()

.constructCollectionType(collectionClass, elementClass);

return mapper.readValue(jsonString, type);

} catch (Exception e) {

logger.error("parse json string error:" + jsonString, e);

return null;

}

}

/**

* 反序列化复杂类型

* 针对复杂类型反序列化时，自动转化为LinkedHashMap问题

* @param jsonString

* @param typeRef 自定义解析器类型

* @return

*/

public static T fromJson(String jsonString, TypeReference typeRef) {

if (StringUtils.isBlank(jsonString)) {

return null;

}

try {

return mapper.readValue(jsonString, typeRef);

} catch (Exception e) {

logger.error("parse json string error:" + jsonString, e);

return null;

}

}

public static ,L extends Collection, E> M fromJson(String jsonString,

Class mapClass, Class collectionClass, Class elementClass) {

if (StringUtils.isBlank(jsonString)) {

return null;

}

try {

return mapper.readValue(jsonString, new TypeReference() {});

} catch (Exception e) {

logger.error("parse json string error:" + jsonString, e);

return null;

}

}

/**

* 当JSON里只含有Bean的部分属性，更新一个已存在Bean，只覆盖该部分的属性.

*/

public static void update(String jsonString, Object object) {

try {

mapper.readerForUpdating(object).readValue(jsonString);

} catch (JsonProcessingException e) {

logger.error("update json string:" + jsonString + " to object:"

+ object + " error.", e);

} catch (IOException e) {

logger.error("update json string:" + jsonString + " to object:"

+ object + " error.", e);

}

}

/**

* 转换JSON对象为ajax的方式

* ex.{"success":"false","data":{"name":"名称已存在"}}

*

* @param obj

* 错误信息，若用map，Key若为表单项的name，则会自动在对应表单项显示错误信息

*/

public static String toFormJson(Object obj, boolean success) {

Map map = new HashMap();

map.put("success", success);

map.put("data", obj);

try {

return mapper.writeValueAsString(map);

} catch (JsonProcessingException e) {

logger.error("write to json string error:" + obj, e);

return null;

}

}

/**

* 输出JSONP格式数据

*/

public static String toJsonP(String functionName, Object object) {

return toJson(new JSONPObject(functionName, object));

}

/**

* 将Object转换成Json，维持多态类型.

* 该Json不能用于rest请求

* @return

*/

public static String toJsonAsPolymorphism(Object obj){

try {

return mapperWithType.writeValueAsString(obj);

} catch (JsonProcessingException e) {

logger.error(e.getMessage());

}

return null;

}

/**

* 将Json转换成Object，维持多态类型.

* 该转换不能用于rest响应

* @return

*/

public static T fromJsonAsPolymorphism(String json,Class clazz){

try {

return mapperWithType.readValue(json, clazz);

} catch (IOException e) {

logger.error(e.getMessage());

}

return null;

}

}