在 Parse 后端查找当前时间和上次更新时间之间的差异

Question

我正在尝试编写一个 Java 脚本来计算当前日期与存储在我们的 Parse 后端的最后更新时间之间的时差。谁能帮我找出代码中的错误？你可能认为这还不错，但我已经查看 Stack Overflow 数小时但无济于事。

//Create a date formatter.
        SimpleDateFormat formatter=new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'.'LLL'Z'");
//Create a date object for today's date.
        Date currentDate=new Date();
//Create a string for the date from parse.
        String parseTime = singleClaim.getString("updatedAt");
//Create a string for the current date.
        String currentTime=currentDate.toString();
//Initialize the date object for the updatedAt time on Parse.
        Date parseDate = null;
//Initialize the date object for the current time.
        Date FormattedCurrentDate = null;
        try {
//Here, we convert the parseTime string into a date object and format it.
            parseDate = formatter.parse(parseTime);
//Here, we convert the currentTime string into a date object and format it.
            FormattedCurrentDate = formatter.parse(currentTime);
} 

        catch (Exception e) {
            e.printStackTrace();
        }           

   //Get the time difference from the current date versus the date on Parse.
        long difference = FormattedCurrentDate.getTime()-parseDate.getTime();

Answer 1

您不应调用 toString() 将 Date 转换为 String。为什么要将 currentTime 转换为 String 然后再将其解析为日期？这毫无意义。

//Create a date formatter.
        SimpleDateFormat formatter=new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'.'LLL'Z'");
//Create a date object for today's date.
        Date currentDate=new Date();
//Create a string for the date from parse.
        String parseTime = singleClaim.getString("updatedAt");
//Create a string for the current date.
        String currentTime=currentDate.toString();
//Initialize the date object for the updatedAt time on Parse.
        Date parseDate = null;
        try {
//Here, we convert the parseTime string into a date object and format it.
            parseDate = formatter.parse(parseTime);
} 

        catch (Exception e) {
            e.printStackTrace();
        }           

   //Get the time difference from the current date versus the date on Parse.
        long difference = currentDate.getTime()-parseDate.getTime();

Answer 2

这两行的组合可能导致了您的问题：

String currentTime=currentDate.toString();
// ...
FormattedCurrentDate = formatter.parse(currentTime);

currentTime 变量不包含格式化程序可以使用的格式正确的字符串。

我也觉得没有必要创建这样的字符串，您可以按如下方式创建：

long difference = currentDate.getTime() - parseDate.getTime();

如果您绝对坚持从日期到字符串再返回，则必须按如下方式创建 currentTime 字符串：

currentTime = formatter.format(currentDate);

在 Parse 后端查找当前时间和上次更新时间之间的差异

Finding the difference between current time and last updated time on Parse backend

java

date

time

parse-platform

simpledateformat