“找不到主要类：XX。程序将退出。“ [英] "Could not find the main class: XX. Program will exit."

问题描述

我设法用命令提示符运行我的jar文件，但它总是给我一个响应

I have managed to run my jar file with a command prompt, but its always giving me a reponse of

找不到主要类：XX。程序将退出。

Could not find the main class: XX. Program will exit.

请帮助我，谢谢。

推荐答案

请参阅设置应用程序的入口点

如果你有一个捆绑在JAR文件中的应用程序，你需要一些方法来指示JAR文件中的哪个类是您的应用程序的入口点。您使用清单中的Main-Class标头提供此信息，其标题为：

If you have an application bundled in a JAR file, you need some way to indicate which class within the JAR file is your application's entry point. You provide this information with the Main-Class header in the manifest, which has the general form:

Main-Class: classname

值classname是名称作为应用程序入口点的类。

The value classname is the name of the class that is your application's entry point.

回想一下，入口点是一个具有签名方法的类

Recall that the entry point is a class having a method with signature

 public static void main(String[] args).

在清单中设置Main-Class标头后，然后使用以下命令运行JAR文件以下形式的java命令：

After you have set the Main-Class header in the manifest, you then run the JAR file using the following form of the java command:

java -jar JAR-name

执行Main-Class标头中指定的类的主要方法。

The main method of the class specified in the Main-Class header is executed.

我们首先创建一个名为Manifest.txt的文本文件，其中包含以下内容：

We first create a text file named Manifest.txt with the following contents:

Main-Class: MyPackage.MyClass

警告：文本文件必须以新行或回车结尾。如果不以新行或回车结束，则不会正确解析最后一行。

Warning: The text file must end with a new line or carriage return. The last line will not be parsed properly if it does not end with a new line or carriage return.

然后输入以下命令创建一个名为MyJar.jar的JAR文件：

We then create a JAR file named MyJar.jar by entering the following command:

jar cfm MyJar.jar Manifest.txt MyPackage/*.class

这将创建一个带有以下内容的清单的JAR文件：

This creates the JAR file with a manifest with the following contents:

Manifest-Version: 1.0
Created-By: 1.6.0 (Sun Microsystems Inc.)
Main-Class: MyPackage.MyClass

使用以下命令运行JAR文件时，MyClass的main方法执行：

When you run the JAR file with the following command, the main method of MyClass executes:

java -jar MyJar.jar

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