code: public static String encodeAsString(Object obj,NamingStyle namingStyle,boolean useUnicode){
  		SerializeConfig config = SerializeConfig.getGlobalInstance();
  		config.propertyNamingStrategy = getNamingStrategy(namingStyle);
  		if(useUnicode){
  			return JSON.toJSONString(obj,config,
  							SerializerFeature.BrowserCompatible,
  							SerializerFeature.WriteNullListAsEmpty,
  							SerializerFeature.NotWriteDefaultValue
  							);
  		}
  		return JSON.toJSONString(obj,config);
  	}
docs: 将指定java对象序列化成相应字符串
  @param obj java对象
  @param namingStyle 命名风格
  @param useUnicode 是否使用unicode编码（当有中文字段时）
  @return 序列化后的json字符串
  @author Zhanghongdong