我正在尝试从Windows中的命令行执行Java程序。这是我的代码:

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class CopyFile
{
    public static void main(String[] args)
    {

        InputStream inStream = null;
        OutputStream outStream = null;

        try
        {

            File afile = new File("input.txt");
            File bfile = new File("inputCopy.txt");

            inStream = new FileInputStream(afile);
            outStream = new FileOutputStream(bfile);

            byte[] buffer = new byte[1024];

            int length;
            // copy the file content in bytes
            while ((length = inStream.read(buffer)) > 0)
            {

                outStream.write(buffer, 0, length);

            }

            inStream.close();
            outStream.close();

            System.out.println("File is copied successful!");

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

我不知道如何执行这个程序——有什么帮助吗?这在Windows上可行吗?为什么它与其他环境不同(我以为JVM是一次编写,随处运行)?


当前回答

来源:javaindos。

Let's say your file is in C:\mywork\ Run Command Prompt C:\> cd \mywork This makes C:\mywork the current directory. C:\mywork> dir This displays the directory contents. You should see filenamehere.java among the files. C:\mywork> set path=%path%;C:\Program Files\Java\jdk1.5.0_09\bin This tells the system where to find JDK programs. C:\mywork> javac filenamehere.java This runs javac.exe, the compiler. You should see nothing but the next system prompt... C:\mywork> dir javac has created the filenamehere.class file. You should see filenamehere.java and filenamehere.class among the files. C:\mywork> java filenamehere This runs the Java interpreter. You should then see your program output. If the system cannot find javac, check the set path command. If javac runs but you get errors, check your Java text. If the program compiles but you get an exception, check the spelling and capitalization in the file name and the class name and the java HelloWorld command. Java is case-sensitive!

其他回答

来源:javaindos。

Let's say your file is in C:\mywork\ Run Command Prompt C:\> cd \mywork This makes C:\mywork the current directory. C:\mywork> dir This displays the directory contents. You should see filenamehere.java among the files. C:\mywork> set path=%path%;C:\Program Files\Java\jdk1.5.0_09\bin This tells the system where to find JDK programs. C:\mywork> javac filenamehere.java This runs javac.exe, the compiler. You should see nothing but the next system prompt... C:\mywork> dir javac has created the filenamehere.class file. You should see filenamehere.java and filenamehere.class among the files. C:\mywork> java filenamehere This runs the Java interpreter. You should then see your program output. If the system cannot find javac, check the set path command. If javac runs but you get errors, check your Java text. If the program compiles but you get an exception, check the spelling and capitalization in the file name and the class name and the java HelloWorld command. Java is case-sensitive!

你可以在命令行中使用javac编译任何java源代码;例如,javac CopyFile.java。 执行命令:java CopyFile。 你也可以使用javac *.java编译所有的java文件,只要它们在同一个目录下

如果你有一个问题导致“无法找到或加载主类”,你可能没有 Jre在你的路径。看看这个问题: 无法找到或加载主类

现在(从JDK 9开始),您可以使用java来执行该命令。 为了执行包含main的"Hello.java",可以使用: java Hello.java

你不再需要单独使用javac进行编译。

在Windows 7上,我必须执行以下操作:

快速的方法

Install JDK http://www.oracle.com/technetwork/java/javase/downloads in windows, browse into "C:\Program Files\Java\jdk1.8.0_91\bin" (or wherever the latest version of JDK is installed), hold down shift and right click on a blank area within the window and do "open command window here" and this will give you a command line and access to all the BIN tools. "javac" is not by default in the windows system PATH environment variable. Follow comments above about how to compile the file ("javac MyFile.java" then "java MyFile") https://stackoverflow.com/a/33149828/194872

漫长的道路

Install JDK http://www.oracle.com/technetwork/java/javase/downloads/index.html After installing, in edits the Windows PATH environment variable and adds the following to the path C:\ProgramData\Oracle\Java\javapath. Within this folder are symbolic links to a handful of java executables but "javac" is NOT one of them so when trying to run "javac" from Windows command line it throws an error. I edited the path: Control Panel -> System -> Advanced tab -> "Environment Variables..." button -> scroll down to "Path", highlight and edit -> replaced the "C:\ProgramData\Oracle\Java\javapath" with a direct path to the java BIN folder "C:\Program Files\Java\jdk1.8.0_91\bin". This likely breaks when you upgrade your JDK installation but you have access to all the command line tools now. Follow comments above about how to compile the file ("javac MyFile.java" then "java MyFile") https://stackoverflow.com/a/33149828/194872

第一步:首先打开文件所在的命令提示符。(按住shift键右键点击) 步骤2:然后使用以下命令执行。 (假设要执行的文件和类名为Student.java)示例程序在图片背景中。

     javac Student.java
     java Student