将 HTML 日期输入解析为 Java Servlet 中的时间戳

Question

最近我遇到了时间戳和 HTML 输入类型日期的问题：

这是我的 HTML/JSP:

<div class="form-group">
   <label>Your day of birth</label>
   <input class="form-control form-control-lg" type="date" name="txtBirthdate" required="">
</div>

这是我的 Java Servlet：

String birth = request.getParameter(Constants.BIRTHDATE_TXT);
System.out.println(birth);
Timestamp bDate = new Timestamp(((new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(birth)).getTime()));
System.out.println(bDate);
Timestamp joinDate = new Timestamp(Calendar.getInstance().getTime().getTime());

我无法将 String birth 解析为 Timestamp，有什么方法可以转换它吗？当您使用 SimpleDateFormat 删除 yyyy-MM-dd 字符串时，我也是对的，它会将 HH:mm:ss 部分设置为默认值为 00:00:0000?

感谢您的帮助

Answer 1

java.util 的日期时间 API 及其格式 API、SimpleDateFormat 已过时且容易出错。请注意，java.sql.Timestamp 继承了扩展 java.util.Date 的相同缺点。建议完全停止使用它们并切换到 modern date-time API. For any reason, if you have to stick to Java 6 or Java 7, you can use ThreeTen-Backport which backports most of the java.time functionality to Java 6 & 7. If you are working for an Android project and your Android API level is still not compliant with Java-8, check Java 8+ APIs available through desugaring and .

你提到过，

My problem is I don't really know how to parse date like example: "2020-12-28" into Timestamp

你也提到了，

And also am I right when you pare the yyyy-MM-dd string using the SimpleDateFormat, it will set the HH:mm:ss part with default value is 00:00:0000?

从这两个要求，我推断你需要一个日期，例如2020-12-28 结合时间，例如00:00:00 这只不过是一天的开始。 java.time 提供了一个干净的 API, LocalDate#atStartOfDay 来实现这个。

演示：

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Locale;

public class Main {
    public static void main(String[] args) {
        String strDate = "2020-12-28";

        // Parse the given date string into LocalDate. Note that you do not need a
        // DateTimeFormatter to parse it as it is already in ISO 8601 format
        LocalDate date = LocalDate.parse(strDate);

        // Note: In the following line, replace ZoneId.systemDefault() with the required
        // Zone ID which specified in the format, Continent/City e.g.
        // ZoneId.of("Europe/London")
        ZonedDateTime zdt = date.atStartOfDay(ZoneId.systemDefault());

        // Print the default format i.e. the value of zdt#toString. Note that the
        // default format omits seconds and next smaller units if seconds part is zero
        System.out.println(zdt);

        // Get and print just the date-time without timezone information
        LocalDateTime ldt = zdt.toLocalDateTime();
        System.out.println(ldt);

        // Get and print zdt in a custom format
        DateTimeFormatter dtf = DateTimeFormatter.ofPattern("uuuu-MM-dd'T'HH:mm:ss.SSS", Locale.ENGLISH);
        String formatted = zdt.format(dtf);
        System.out.println(formatted);
    }
}

输出：

2020-12-28T00:00Z[Europe/London]
2020-12-28T00:00
2020-12-28T00:00:00.000

从 Trail: Date Time.

了解现代日期时间 API

将 HTML 日期输入解析为 Java Servlet 中的时间戳

Parsing HTML date input into Timestamp in Java Servlet

java

timestamp

simpledateformat

java.util.date

java.util.calendar