使用Eclipse时,Maven编译失败并显示"找不到符号",它编译

Question

我在Maven中有一个编译错误但在Eclipse中一切顺利.

有什么我做错了或是Maven bug吗？

我创建了一个代码片段,因此您可以尝试重现它.

以下是Java源文件和pom.xml.

package p1;

import p1.A.D.C;
import p1.p2.E;

public class A {
    interface B<T> {
        T methodB();
    }

    class D implements B<E> {
        C c = new C();

        public C getC() {
            return c;
        }

        class C {
            public void methodC() {
                System.out.println(this);
            }
        }

        @Override
        public E methodB() {
            return new E();
        }
    }

    public void methodA() {
        D d = new D();
        d.methodB();
        C c = d.getC();
        c.methodC();
    }

    public static void main(String[] args) {
        A a = new A();
        a.methodA();
    }
}

package p1.p2;

public class E {
}

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>mvntst</groupId>
  <artifactId>test</artifactId>
  <version>0</version>
  <packaging>jar</packaging>
  <name>mvntst</name>
</project>

当我运行时mvn clean compile,我得到这个输出:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project test: Compilation failure
[ERROR] /C:/dev/test/CompilerTest/MavenTest/src/main/java/p1/A.java:[6,30] cannot find symbol
[ERROR] symbol:   class E                                                                                                                       
[ERROR] location: class p1.A
[ERROR] -> [Help 1]                                                                                                                             
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.                                                             
[ERROR] Re-run Maven using the -X switch to enable full debug logging.                                                                          
[ERROR]                                                                                                                                         
[ERROR] For more information about the errors and possible solutions, please read the following articles:                                       
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

结果如下mvn --version:

Apache Maven 3.3.1 (cab6659f9874fa96462afef40fcf6bc033d58c1c; 2015-03-13T23:10:27+03:00)
Maven home: C:\dev\apache-maven-3.3.1\bin\..
Java version: 1.8.0_40, vendor: Oracle Corporation
Java home: C:\Program Files\Java\jdk1.8.0_40\jre
Default locale: en_US, platform encoding: Cp1252
OS name: "windows 7", version: "6.1", arch: "amd64", family: "dos"

Answer 1

如果您颠倒导入顺序...

import p1.p2.E;
import p1.A.D.C;

...它会编译得很好。这可能是由于编译器假定文件夹 A、D 和 C 存在于 之下p1，但事实并非如此。

但您不应该这样做（感觉不对），而应该改变C引入methodA.

public void methodA() {
    D d = new D();
    d.methodB();
    D.C c = d.getC();
    c.methodC();
}

您也可以摆脱内部类的导入，因为上面的内容不再需要。