/**
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* Copyright © 2015-2020 <a href="http://www.jeeplus.org/">JeePlus</a> All rights reserved.
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*/
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package com.jeeplus.common.mapper;
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import java.io.IOException;
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import java.util.List;
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import java.util.Map;
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import java.util.TimeZone;
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import org.apache.commons.lang3.StringEscapeUtils;
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import org.apache.commons.lang3.StringUtils;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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import com.fasterxml.jackson.annotation.JsonInclude.Include;
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import com.fasterxml.jackson.core.JsonGenerator;
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import com.fasterxml.jackson.core.JsonProcessingException;
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import com.fasterxml.jackson.core.JsonParser.Feature;
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import com.fasterxml.jackson.databind.DeserializationFeature;
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import com.fasterxml.jackson.databind.JavaType;
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import com.fasterxml.jackson.databind.JsonSerializer;
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import com.fasterxml.jackson.databind.ObjectMapper;
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import com.fasterxml.jackson.databind.SerializationFeature;
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import com.fasterxml.jackson.databind.SerializerProvider;
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import com.fasterxml.jackson.databind.module.SimpleModule;
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import com.fasterxml.jackson.databind.util.JSONPObject;
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import com.fasterxml.jackson.module.jaxb.JaxbAnnotationModule;
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import com.google.common.collect.Lists;
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import com.google.common.collect.Maps;
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/**
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* 简单封装Jackson，实现JSON String<->Java Object的Mapper.
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* 封装不同的输出风格, 使用不同的builder函数创建实例.
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* @author jeeplus
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* @version 2013-11-15
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*/
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public class JsonMapper extends ObjectMapper {
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private static final long serialVersionUID = 1L;
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private static Logger logger = LoggerFactory.getLogger(JsonMapper.class);
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private static JsonMapper mapper;
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public JsonMapper() {
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//this(Include.NON_EMPTY);
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}
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public JsonMapper(Include include) {
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// 设置输出时包含属性的风格
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if (include != null) {
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this.setSerializationInclusion(include);
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}
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// 允许单引号、允许不带引号的字段名称
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this.enableSimple();
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// 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
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this.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
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// 空值处理为空串
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this.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>(){
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@Override
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public void serialize(Object value, JsonGenerator jgen,
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SerializerProvider provider) throws IOException,
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JsonProcessingException {
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jgen.writeString("");
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}
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});
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// 进行HTML解码。
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this.registerModule(new SimpleModule().addSerializer(String.class, new JsonSerializer<String>(){
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@Override
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public void serialize(String value, JsonGenerator jgen,
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SerializerProvider provider) throws IOException,
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JsonProcessingException {
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jgen.writeString(StringEscapeUtils.unescapeHtml4(value));
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}
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}));
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// 设置时区
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this.setTimeZone(TimeZone.getDefault());//getTimeZone("GMT+8:00")
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}
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/**
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* 创建只输出非Null且非Empty(如List.isEmpty)的属性到Json字符串的Mapper,建议在外部接口中使用.
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*/
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public static JsonMapper getInstance() {
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if (mapper == null){
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mapper = new JsonMapper().enableSimple();
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}
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return mapper;
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}
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/**
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* 创建只输出初始值被改变的属性到Json字符串的Mapper, 最节约的存储方式，建议在内部接口中使用。
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*/
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public static JsonMapper nonDefaultMapper() {
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if (mapper == null){
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mapper = new JsonMapper(Include.NON_DEFAULT);
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}
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return mapper;
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}
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/**
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* Object可以是POJO，也可以是Collection或数组。
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* 如果对象为Null, 返回"null".
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* 如果集合为空集合, 返回"[]".
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*/
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public String toJson(Object object) {
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try {
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return this.writeValueAsString(object);
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} catch (IOException e) {
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logger.warn("write to json string error:" + object, e);
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return null;
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}
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}
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/**
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* 反序列化POJO或简单Collection如List<String>.
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*
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* 如果JSON字符串为Null或"null"字符串, 返回Null.
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* 如果JSON字符串为"[]", 返回空集合.
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*
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* 如需反序列化复杂Collection如List<MyBean>, 请使用fromJson(String,JavaType)
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* @see #fromJson(String, JavaType)
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*/
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public <T> T fromJson(String jsonString, Class<T> clazz) {
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if (StringUtils.isEmpty(jsonString)) {
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return null;
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}
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try {
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return this.readValue(jsonString, clazz);
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} catch (IOException e) {
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logger.warn("parse json string error:" + jsonString, e);
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return null;
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}
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}
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/**
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* 反序列化复杂Collection如List<Bean>, 先使用函數createCollectionType构造类型,然后调用本函数.
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* @see #createCollectionType(Class, Class...)
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*/
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@SuppressWarnings("unchecked")
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public <T> T fromJson(String jsonString, JavaType javaType) {
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if (StringUtils.isEmpty(jsonString)) {
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return null;
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}
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try {
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return (T) this.readValue(jsonString, javaType);
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} catch (IOException e) {
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logger.warn("parse json string error:" + jsonString, e);
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return null;
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}
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}
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/**
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* 構造泛型的Collection Type如:
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* ArrayList<MyBean>, 则调用constructCollectionType(ArrayList.class,MyBean.class)
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* HashMap<String,MyBean>, 则调用(HashMap.class,String.class, MyBean.class)
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*/
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public JavaType createCollectionType(Class<?> collectionClass, Class<?>... elementClasses) {
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return this.getTypeFactory().constructParametricType(collectionClass, elementClasses);
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}
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/**
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* 當JSON裡只含有Bean的部分屬性時，更新一個已存在Bean，只覆蓋該部分的屬性.
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*/
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@SuppressWarnings("unchecked")
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public <T> T update(String jsonString, T object) {
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try {
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return (T) this.readerForUpdating(object).readValue(jsonString);
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} catch (JsonProcessingException e) {
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logger.warn("update json string:" + jsonString + " to object:" + object + " error.", e);
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} catch (IOException e) {
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logger.warn("update json string:" + jsonString + " to object:" + object + " error.", e);
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}
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return null;
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}
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/**
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* 輸出JSONP格式數據.
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*/
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public String toJsonP(String functionName, Object object) {
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return toJson(new JSONPObject(functionName, object));
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}
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/**
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* 設定是否使用Enum的toString函數來讀寫Enum,
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* 為False時時使用Enum的name()函數來讀寫Enum, 默認為False.
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* 注意本函數一定要在Mapper創建後, 所有的讀寫動作之前調用.
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*/
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public JsonMapper enableEnumUseToString() {
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this.enable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
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this.enable(DeserializationFeature.READ_ENUMS_USING_TO_STRING);
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return this;
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}
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/**
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* 支持使用Jaxb的Annotation，使得POJO上的annotation不用与Jackson耦合。
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* 默认会先查找jaxb的annotation，如果找不到再找jackson的。
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*/
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public JsonMapper enableJaxbAnnotation() {
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JaxbAnnotationModule module = new JaxbAnnotationModule();
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this.registerModule(module);
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return this;
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}
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/**
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* 允许单引号
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* 允许不带引号的字段名称
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*/
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public JsonMapper enableSimple() {
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this.configure(Feature.ALLOW_SINGLE_QUOTES, true);
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this.configure(Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
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return this;
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}
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/**
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* 取出Mapper做进一步的设置或使用其他序列化API.
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*/
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public ObjectMapper getMapper() {
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return this;
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}
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/**
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* 对象转换为JSON字符串
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* @param object
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* @return
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*/
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public static String toJsonString(Object object){
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return JsonMapper.getInstance().toJson(object);
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}
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/**
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* JSON字符串转换为对象
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* @param jsonString
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* @param clazz
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* @return
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*/
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public static Object fromJsonString(String jsonString, Class<?> clazz){
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return JsonMapper.getInstance().fromJson(jsonString, clazz);
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}
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/**
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* 测试
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*/
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public static void main(String[] args) {
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List<Map<String, Object>> list = Lists.newArrayList();
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Map<String, Object> map = Maps.newHashMap();
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map.put("id", 1);
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map.put("pId", -1);
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map.put("name", "根节点");
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list.add(map);
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map = Maps.newHashMap();
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map.put("id", 2);
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map.put("pId", 1);
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map.put("name", "你好");
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map.put("open", true);
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list.add(map);
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String json = JsonMapper.getInstance().toJson(list);
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System.out.println(json);
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}
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}
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