java junit 找不到类
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junit cannot find class
提问by n as
I am able to run the sample tests supplied with junit (from any directory). I would think that this suggests my installation of junit is perfectly fine.
I assume, to compile a junit test, it is no different from any other java file, namely: javac fileName.java
My test file (.java and resulting .class) lives in: c:\parent\child. Obviously, in order to compile the .java file, I have a package statement on the first line: package parent.child followed by the all-important: import junit.framework.TestCase; After this, there is a public class fileName definition extends TestCase {}. The file compiles without any warnings or errors.
when I attempt (in the c:\parent\child directory where fileName exists, both the .java and .class):
我能够运行 junit 提供的示例测试（从任何目录）。我认为这表明我安装的 junit 非常好。
我假设，要编译一个 junit 测试，它与任何其他 java 文件没有什么不同，即： javac fileName.java
我的测试文件（.java 和生成的 .class）位于：c:\parent\child。显然，为了编译 .java 文件，我在第一行有一个 package 语句： package parent.child 后跟最重要的： import junit.framework.TestCase; 在此之后，有一个公共类 fileName 定义 extends TestCase {}。该文件编译时没有任何警告或错误。
当我尝试时（在文件名存在的 c:\parent\child 目录中，.java 和 .class）：
java org.junit.runner.JUnitCore parent.child.fileName, I get the following: JUnit version 4.1 Could not find class: parent.child.fileName Time: 0 OK (0 tests)
java org.junit.runner.JUnitCore parent.child.fileName，我得到以下信息：JUnit 4.1 版找不到类：parent.child.fileName 时间：0 OK（0 次测试）
Even if I drop parent.child altogether from the command, it makes no difference.
My CLASSPATH environment variable is set to: c:\parent\junit\junit-4.1.jar;c:\parent\junit;.
If I trying running with -cp c:\ or c:\parent\child or anything else, I still get the error.
即使我从命令中完全删除 parent.child，也没有区别。
我的 CLASSPATH 环境变量设置为：c:\parent\junit\junit-4.1.jar;c:\parent\junit;。
如果我尝试使用 -cp c:\ 或 c:\parent\child 或其他任何东西运行，我仍然会收到错误消息。
回答by Ernest Friedman-Hill
Java package names are actually part of the class name, and they're also used in a specific way to find *.classfiles. If Java wants to find a class named parent.child.fileName, it's going to look for a file named parent/child/fileName.class-- i.e., it's going to look for the file in a directory named childin a directory named parent. You have to specify the class path such that the parentdirectory will be found, something like
Java 包名实际上是类名的一部分，它们也以特定方式用于查找*.class文件。如果 Java 想要找到一个名为 的类parent.child.fileName，它将寻找一个名为的文件parent/child/fileName.class——也就是说，它将child在名为parent. 您必须指定类路径parent以便找到目录，例如
java -cp "c:/junit/junit.jar;c:/" org.junit.runner.JUnitCore parent.child.fileName
The class path (-cp) argument has to specify all the places that Java should look for classes, including jar files like junit.jar, which I've imagined is located in a directory called junit. The semicolon ";" is used to separate entries on the class path (assuming you're using Windows; on real computers it's a ":" instead.) The "c:/" entry in the class path is the one that will be used to find the parentdirectory and thus your class.
类路径 (-cp) 参数必须指定 Java 应该查找类的所有位置，包括 jar 文件junit.jar，我认为它位于名为junit. 分号“;” 用于分隔类路径上的条目（假设您使用的是 Windows；在真实计算机上，它是一个“:”。）类路径中的“c:/”条目将用于查找parent目录因此你的班级。
回答by ArturSkowronski
You should use JUnit Runner to run test outside IDE, not only compile it.
您应该使用 JUnit Runner 在 IDE 之外运行测试，而不仅仅是编译它。
java -cp lib/junit.jar;sw.jar org.junit.runner.JUnitCore your.package.fileName
update this line to yours project structure.
将此行更新为您的项目结构。
回答by hiflyer
In general it's so much easier to run unit tests using a build system like ant/maven/gradle or from within your IDE (IntelliJ/eclipse/Netbeans)
一般来说，使用诸如 ant/maven/gradle 之类的构建系统或从您的 IDE (IntelliJ/eclipse/Netbeans) 中运行单元测试要容易得多
