java jar 中的 System.out.println
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System.out.println in jar
提问by Dallox
I have this java program that I want to package within a jar. It compiles fine and it compiles without errors into a jar. But when I double click it, it wont start. I know most jar applications uses JFrame and that works fine. But is it possible to make it command prompt/shell based? (Like Displaying System.out.println)
我有这个 java 程序，我想将它打包在一个 jar 中。它编译得很好，并且编译成 jar 没有错误。但是当我双击它时，它不会启动。我知道大多数 jar 应用程序使用 JFrame 并且工作正常。但是有可能使它基于命令提示符/shell吗？（比如显示 System.out.println）
Example is it possible to execute this code by double clicking a jar:
示例是否可以通过双击 jar 来执行此代码：
public class Hello
{
public static void main( String[] args )
{
System.out.println( "Hello, World!" );
}
}
回答by Carlos Tasada
There is no problem doing like that. But where do you expect to see the output?
这样做没有问题。但是您希望在哪里看到输出？
If you execute from the console as java -jar my jar.jaryou will see your "Hello, World".
如果您从控制台执行，java -jar my jar.jar您将看到“Hello, World”。
If you want to double-click you'll need to create a JFrame.
如果要双击，则需要创建一个 JFrame。
回答by Jeffrey
You can change the file association for jar files to have them open a console. (This is for Windows)
您可以更改 jar 文件的文件关联以让它们打开控制台。（这是针对 Windows 的）
- Open Command Processor
- Type
ftype jarfile - You will get something like:
- 打开命令处理器
- 类型
ftype jarfile - 你会得到类似的东西：
jarfile="C:\Path\To\Java\bin\javaw.exe" -jar "%1 %*"
jarfile="C:\Path\To\Java\bin\javaw.exe" -jar "%1 %*"
- Enter
ftype jarfile "C:\Path\To\Java\bin\java.exe" -jar "%1" %*(You may need administrator privileges to do this).
- Enter
ftype jarfile "C:\Path\To\Java\bin\java.exe" -jar "%1" %*（您可能需要管理员权限才能执行此操作）。
回答by Marko Topolnik
I don't see anyone mentioning the obvious solution: make a .cmd (or .bat) file containing the command everyone is talking about -- java -jar YourJar.jar. You can double-click on the .cmd file and a console window will open. It will also close imediately as your program exits, so the program should wait for a keypress before exiting.
我没有看到有人提到明显的解决方案：制作一个 .cmd（或 .bat）文件，其中包含每个人都在谈论的命令 -- java -jar YourJar.jar。您可以双击 .cmd 文件，将打开一个控制台窗口。它也会在您的程序退出时立即关闭，因此程序应该在退出之前等待按键。
回答by Marko Topolnik
The output gets forwarded to the console but without eclipse, there isn't any! The only way to work around this is to launch the program in command prompt and then you will get the output from the program.
输出被转发到控制台，但没有 Eclipse，就没有！解决此问题的唯一方法是在命令提示符下启动该程序，然后您将获得该程序的输出。
回答by Raam
回答by AlexR
Sure. First try to run your program as following:
当然。首先尝试运行您的程序，如下所示：
java -cp yourjar.jar Main
java -cp yourjar.jar Main
where Main is a fully qualified class name of your main class.
其中 Main 是主类的完全限定类名。
When this is working fine and if you creted exacutablejar try to run your program as following:
当这工作正常并且您创建了可执行的jar 时，请尝试按如下方式运行您的程序：
java -jar yourjar.jar
java -jar yourjar.jar
When this is working double click should work too unless you mapped extension jarto program other than javawthat is done by default when you are installing JRE.
当这工作时，双击也应该工作，除非您在安装 JRE 时默认情况下将扩展映射jar到程序以外的程序javaw。
回答by imanis_tn
If you want to display the "Hello, world!" String you have to execute your code from the command line:
如果要显示“Hello, world!” 您必须从命令行执行代码的字符串：
jar -jar your_jar_name.jar
