如何在java中将文件写入特定文件夹？

我用robot类和BuffereImage类做了这个截图程序。包含截图的.png文件将保存到存在.java文件的文件夹中。我希望将图像文件写入我创建的另一个名为screenshot的文件夹中。我尝试重命名文件，也尝试使用inputstream和outputstream类进行复制，但结果相同。我怎样才能克服这个问题？我使用Windows8和Java1.8.0

package screenshot;

//Packages imported for the program

import java.io.*;
import java.nio.file.*;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import java.util.*;
import java.text.*;

//Class logic written beside each statement

public class Screenshot 
{

   public static void main(String[] args) 
   {       

     try                                                                                    
     {                                                //Exception Handling
        SimpleDateFormat df=new SimpleDateFormat("dd-MM-yy H-m'.png'");                   //Setting the date format 
        Date date=new Date();                                                             //Getting the current date and time
        String ref=df.format(date);                                                       //Formatting the current date in the SDF constructor's format
        //String dirname="M:\\Java\\bin\\screenshot\\";
        System.out.println(ref);                                                          //Testing whether the current date is getting displayed in the desired format
        Robot robot = new Robot();                                                        //Instanciating the Robot class       
        Rectangle captureSize = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize());          //Declaring a rectangle with size of the screen
        BufferedImage bufferedImage = robot.createScreenCapture(captureSize);                        //Capturing the screenshot and save it in Buffered image object
        //File dir = new File(dirname);
        //File filen = new File("M:\\Java\\bin\\screenshot\\temp.png");
        File filename = new File(ref);
        ImageIO.write(bufferedImage, "png" , filename); //writing the image to a file called filename

     }
    catch(Exception e) 
    {
       System.err.println(e);  //Exception message display
    }
   }

}

---

要将文件存储到文件夹

屏幕截图

，请更改变量

String ref=df.format(date);

到

---

它会将文件保存到该文件夹。

您尝试过这个吗？注意：我对

File

使用了双参数构造函数，它接受表示目录的

File

和该目录中的文件名。我取消了您描述保存到哪个目录的行的注释，并使用了那个目录

    SimpleDateFormat df=new SimpleDateFormat("dd-MM-yy H-m'.png'");                   //Setting the date format 
    Date date=new Date();                                                             //Getting the current date and time
    String ref=df.format(date);                                                       //Formatting the current date in the SDF constructor's format
    String dirname="M:\\Java\\bin\\screenshot\\";
    System.out.println(ref);                                                          //Testing whether the current date is getting displayed in the desired format
    Robot robot = new Robot();                                                        //Instanciating the Robot class       
    Rectangle captureSize = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize());          //Declaring a rectangle with size of the screen
    BufferedImage bufferedImage = robot.createScreenCapture(captureSize);                        //Capturing the screenshot and save it in Buffered image object
    File dir = new File(dirname);
    File filen = new File("M:\\Java\\bin\\screenshot\\temp.png");
    File filename = new File(filen, ref);
    ImageIO.write(bufferedImage, "png" , filename); //writing the image to a file called filename

---

包名称与目标文件夹的名称相同。更改包名或文件夹名，列出的每个方法都可以正常工作

您注释掉了更改目录的行-为什么？我也尝试过了。没有工作，所以我对它们进行了注释。如果您提供一个帮助，以便我们可以实际运行您的代码，那么我们可以提供更多帮助。但是我没有你的

机器人

课程或

图像

。。。一个MCVE和更多关于出错原因的详细信息将大有帮助。更改文件名，然后尝试…我认为这是因为文件名..尝试使用临时文件名并测试它。。。

    SimpleDateFormat df=new SimpleDateFormat("dd-MM-yy H-m'.png'");                   //Setting the date format 
    Date date=new Date();                                                             //Getting the current date and time
    String ref=df.format(date);                                                       //Formatting the current date in the SDF constructor's format
    String dirname="M:\\Java\\bin\\screenshot\\";
    System.out.println(ref);                                                          //Testing whether the current date is getting displayed in the desired format
    Robot robot = new Robot();                                                        //Instanciating the Robot class       
    Rectangle captureSize = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize());          //Declaring a rectangle with size of the screen
    BufferedImage bufferedImage = robot.createScreenCapture(captureSize);                        //Capturing the screenshot and save it in Buffered image object
    File dir = new File(dirname);
    File filen = new File("M:\\Java\\bin\\screenshot\\temp.png");
    File filename = new File(filen, ref);
    ImageIO.write(bufferedImage, "png" , filename); //writing the image to a file called filename