java - 在Java中: Could not find the main class

Question

当我编写一个独立的客户端并尝试执行它时， 它给了我以下错误:

在 Windows 中运行:

Exception in thread "main" java.lang.NoClassDefFoundError: TestClient
Caused by: java.lang.ClassNotFoundException: TestClient
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
Could not find the main class: TestClient.  Program will exit.

这是在 Linux 中

Exception in thread "main" java.lang.NoClassDefFoundError: TestClient (wrong name: com/tata/bayer/service/TestClient)
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
        at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
Could not find the main class: TestClient.  Program will exit.

现在我得到

C:\Softwares\apache-tomcat-6.0.33\webapps\tkweb-ws-12.0\WEB-INF\classes\com>java com.tata.bayer.service.TestClient
Exception in thread "main" java.lang.NoClassDefFoundError: com/tata/bayer/service/TestClient
Caused by: java.lang.ClassNotFoundException: com.tata.bayer.service.TestClient
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
Could not find the main class: com.tata.bayer.service.TestClient  Program will exit.

Answer 1

看起来你应该运行

java com.tata.bayer.service.TestClient

来自包含“com”的目录，具有适当的目录层次结构，最终通向TestClient.class。

您尚未表明此代码是您自己编译的还是别人提供给您的。如果您自己编译它，您通常应该组织源代码，以便它也反射(reflect)包结构。所以你可能会运行:

javac com/tata/bayer/service/*.java
java com.tata.bayer.service.TestClient

或者也许:

# Keep source and class files separate...
javac -d bin com/tata/bayer/service/*.java
java -classpath bin com.tata.bayer.service.TestClient

如果这没有帮助，请提供更多详细信息。