定义一个字符串或者是获取一个字符串
但是记得一定是json字符串哦
let dictionary_temp = "{\"to\":\"18037517130_8\",\"body\":{\"thumbnailLocalPath\":\"\",\"thumbnailSecretKey\":\"\",\"downloadStatus\":1,\"thumbnailSizeWidth\":0,\"sizeHight\":0,\"localPath\":\"\\/Users\\/tingyuxuan\\/Library\\/Developer\\/CoreSimulator\\/Devices\\/1A6A72D7-A5E4-40C4-9128-958201FA4CF6\\/data\\/Containers\\/Data\\/Application\\/A172FCF4-CEDA-4BF8-95E1-28D68022B65B\\/Documents\\/HyphenateSDK\\/chatbuffer\\/1467694526525.png\",\"remotePath\":\"\",\"secretKey\":\"\",\"sizeWidth\":0,\"thumbnailRemotePath\":\"\",\"thumbnailDownloadStatus\":3},\"messageId\":\"14676945265360040\",\"conversationId\":\"18037517130_8\",\"timestamp\":1467694526536,\"from\":\"18501360583_167\",\"isDeliverAcked\":false,\"isRead\":true,\"chatType\":0,\"serverTime\":1467694526536,\"isReadAcked\":false,\"ext\":{\"questionId_with_Ext\":\"102\",\"body_type\":2},\"status\":1,\"direction\":0}"
我这里是直接复制的获取的json字符串，格式可能不对，表达出意思就行了，大家见谅
if !dictionary_temp.isEmpty{
let data = dictionary_temp.dataUsingEncoding(NSUTF8StringEncoding)! as NSData
let dictionary_temp_temp = try? NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers）
}
判断确定 dictionary_temp不是空的，然后进行转换
转换出来结果是 dictionary_temp_temp 是以字典的形式来呈现的
{
downloadStatus = 1;
localPath = "/Users/tingyuxuan/Library/Developer/CoreSimulator/Devices/1A6A72D7-A5E4-40C4-9128-958201FA4CF6/data/Containers/Data/Application/A172FCF4-CEDA-4BF8-95E1-28D68022B65B/Documents/HyphenateSDK/chatbuffer/1467694526525.png";
remotePath = "";
secretKey = "";
sizeHight = 0;
sizeWidth = 0;
thumbnailDownloadStatus = 3;
thumbnailLocalPath = "";
thumbnailRemotePath = "";
thumbnailSecretKey = "";
thumbnailSizeWidth = 0;
};
chatType = 0;
conversationId = "18037517130_8";
direction = 0;
ext = {
"body_type" = 2;
"questionId_with_Ext" = 102;
};
from = "18501360583_167";
isDeliverAcked = 0;
isRead = 1;
isReadAcked = 0;
messageId = 14676945265360040;
serverTime = 1467694526536;
status = 1;
timestamp = 1467694526536;
to = "18037517130_8";