java 如何获取在java中创建的日期图片

How to get date picture created in java

提问by user16029

I would like to extract the date a jpg file was created. Java has the lastModified method for the File object, but appears to provide no support for extracting the created date from the file. I believe the information is stored within the file as the date I see when I hover the mouse pointer over the file in Win XP is different than what I can get by using JNI with "dir /TC" on the file in DOS.

我想提取创建 jpg 文件的日期。Java 具有 File 对象的 lastModified 方法，但似乎不支持从文件中提取创建日期。我相信信息存储在文件中，因为当我在 Win XP 中将鼠标指针悬停在文件上时我看到的日期与我在 DOS 中在文件上使用带有“dir /TC”的 JNI 获得的日期不同。

回答by amo-ej1

The information is stored within the image in a format called EXIFor link text. There several libraries out there capable of reading this format, like this one

信息以称为EXIF或链接文本的格式存储在图像中。有几个图书馆能够读取这种格式，就像这个

回答by pjz

The date is stored in the EXIFdata in the jpeg. There's a java libraryand a viewer in javathat might be helpful.

日期存储在jpeg 格式的EXIF数据中。有一个java 库和一个java中的查看器可能会有所帮助。

回答by pjz

I use this metadata library: http://www.drewnoakes.com/code/exif/

我使用这个元数据库：http: //www.drewnoakes.com/code/exif/

Seems to work pretty well, although bear in mind that not all JPEG images have this information, so it can't be 100% fool-proof.

似乎工作得很好，但请记住，并非所有 JPEG 图像都具有此信息，因此不能 100% 万无一失。

If the EXIF metadata doesn't contain the created date, then you'll probably have to make do with Java's lastUpdated - unless you want to resort to Runtime.exec(...) and using system functions to find out (I wouldn't recommend this, though!)

如果 EXIF 元数据不包含创建日期，那么您可能不得不使用 Java 的 lastUpdated - 除非您想求助于 Runtime.exec(...) 并使用系统函数来找出（我不会）不过不推荐这个！）

回答by Dan Dyer

You probably need something to access the exifdata. Google suggests this library.

您可能需要一些东西来访问exif数据。谷歌建议使用这个库。

回答by Jorge Ferreira

The code example below asks the user for a file path and then outputs the creation date and time:

下面的代码示例要求用户提供文件路径，然后输出创建日期和时间：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

    public static void main(final String[] args) {
        try {
            // get runtime environment and execute child process
            Runtime systemShell = Runtime.getRuntime();
            BufferedReader br1=new BufferedReader(new InputStreamReader(System.in));
            System.out.println("Enter filename: ");
            String fname=(String)br1.readLine();
            Process output = systemShell.exec("cmd /c dir /a "+fname);
             // open reader to get output from process
            BufferedReader br = new BufferedReader (new InputStreamReader(output.getInputStream()));

            String out="";
            String line = null;

            int step=1;
             while((line = br.readLine()) != null ) 
              {
                 if(step==6)
                {
                out=line;
                }
                 step++;
                 }          // display process output

            try{
            out=out.replaceAll(" ","");
            System.out.println("CreationDate: "+out.substring(0,10));
            System.out.println("CreationTime: "+out.substring(10,15));
            }
            catch(StringIndexOutOfBoundsException se)
            {
                System.out.println("File not found");
            }
            }
          catch (IOException ioe){ System.err.println(ioe); }
          catch (Throwable t) { t.printStackTrace();}
    }
}