Question

当我创建一个新的类文件，或一个新项目，然后是一个类文件时，我的HelloWorld程序始终有效。它编译并运行打印预期结果＆＃34; Hello world＆＃34;

然后，如果我关闭我的Jcreator程序并双击我的helloworld程序再次在Jcreator上打开它并尝试运行它而不是得到相同的结果我得到这个：

Usage: java [-options] class [args...]
          (to execute a class)
    or  java [-options] -jar jarfile [args...]
       (to execute a jar file)
where options include:
-d32      use a 32-bit data model if available
-d64      use a 64-bit data model if available
-client   to select the "client" VM
-server   to select the "server" VM
-hotspot      is a synonym for the "client" VM  [deprecated]
              The default VM is client.

-cp <class search path of directories and zip/jar files>
-classpath <class search path of directories and zip/jar files>
              A ; separated list of directories, JAR archives,
              and ZIP archives to search for class files.
-D<name>=<value>
              set a system property
-verbose:[class|gc|jni]
              enable verbose output
-version      print product version and exit
-version:<value>
              require the specified version to run
-showversion  print product version and continue
-jre-restrict-search | -no-jre-restrict-search
              include/exclude user private JREs in the version search
-? -help      print this help message
-X            print help on non-standard options
-ea[:<packagename>...|:<classname>]
-enableassertions[:<packagename>...|:<classname>]
              enable assertions with specified granularity
-da[:<packagename>...|:<classname>]
-disableassertions[:<packagename>...|:<classname>]
              disable assertions with specified granularity
-esa | -enablesystemassertions
              enable system assertions
-dsa | -disablesystemassertions
              disable system assertions
-agentlib:<libname>[=<options>]
              load native agent library <libname>, e.g. -agentlib:hprof
              see also, -agentlib:jdwp=help and -agentlib:hprof=help
-agentpath:<pathname>[=<options>]
              load native agent library by full pathname
-javaagent:<jarpath>[=<options>]
              load Java programming language agent, see java.lang.instrument
-splash:<imagepath>
              show splash screen with specified image

有关详细信息，请参阅http://www.oracle.com/technetwork/java/javase/documentation/index.html。

你能解释一下我为什么会这样吗？令人尴尬的是无法做到这一点。

感谢。

PS。我的代码没有任何问题，我编译文件时没有错误

Answer 1

它不起作用的原因是因为您只使用单个类文件来运行。由于无法直接执行，您在完成程序时需要执行的操作是导出整个文件。这就是你可以用来运行的东西，而不仅仅是一个类。

当我在Jcreator中重新打开它时，我的hello world程序无效

1 个答案: