Question

下面的代码使用Spring Tool Suite（版本3.9.2）和Java JDK 1.8正常工作（编译和运行）。这是一个常规的Java Web应用程序，其中Spring Framework与Maven处于项目/子项目结构中。

以下课程属于＆＃34;核心＆＃34;模块（子项目）：

package my.core.util;

import java.util.*;
import java.util.function.*;

public interface StreamUtils {

    /**
     * To filter unique by a key
     */
    static <T> Predicate<T> distinctByKey(Function<? super T, ?> keyExtractor) {
        final Set<Object> seen = new HashSet<>();
        return t -> seen.add(keyExtractor.apply(t));
    }
}

使用上述方法的代码（FileServiceImpl.java）属于＆＃34; web＆＃34;模块：

List<DcType> dcTypes = Lists.newArrayList(quote.getDCTypes());
List<DcType> distinct = dcTypes.stream().filter(StreamUtils.distinctByKey(DcType::getId)).collect(Collectors.toList());

但是，如果我运行Maven构建，则会失败并显示以下错误消息：

[INFO] my ................................................. SUCCESS [  2.161 s]
[INFO] my-core ............................................ SUCCESS [01:45 min]
[INFO] my-web ............................................. FAILURE [  3.007 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.7.0:compile (default-compile) on project my-web: Compilation failure
[ERROR] /C:/dev/workspace/my/my-web/src/main/java/my/web/service/FileServiceImpl.java:[43,35] cannot access my.core.util.StreamUtils
[ERROR] bad class file: C:\dev\workspace\my\my-core\target\my-core-1.16.4-SNAPSHOT.jar(my/core/util/StreamUtils.class)
[ERROR] undeclared type variable: T
[ERROR] Please remove or make sure it appears in the correct subdirectory of the classpath.

这是主（root）pom.xml中的Maven插件pom文件配置片段。

<plugin>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.7.0</version>
    <configuration>
        <encoding>UTF-8</encoding>
        <source>1.8</source>
        <target>1.8</target>
        <compilerArgs>
            <arg>-proc:none</arg>
            <arg>-Xlint</arg>
        </compilerArgs>
    </configuration>
</plugin>

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-javadoc-plugin</artifactId>
    <version>3.0.0</version>
    <executions>
        <execution>
            <id>attach-javadocs</id>
            <goals>
                <goal>jar</goal>
            </goals>
            <configuration>
                <skip>true</skip>
                <additionalparam>-Xdoclint:none</additionalparam>
            </configuration>
        </execution>
    </executions>
</plugin>

有趣的是，代码（StreamUtil）通常用于不同的项目中。

使用Maven编译时Generics出错，但在Eclipse中运行正常

0 个答案: