Maven 编译器出错

Question

我目前正在试用 Google Cloud 提供的一些示例代码，但在编译时遇到了问题。以下是我目前正在尝试的示例代码

package com.example;

import com.google.api.client.http.InputStreamContent;
import com.google.api.services.storage.Storage;
import com.google.api.services.storage.model.Bucket;
import com.google.api.services.storage.model.ObjectAccessControl;
import com.google.api.services.storage.model.Objects;
import com.google.api.services.storage.model.StorageObject;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.security.GeneralSecurityException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.io.FileOutputStream;

import javax.servlet.*;
import javax.servlet.http.Part;
import javax.servlet.http.*;

public class upload extends HttpServlet {

/*protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    String Bucket = request.getParameter("Bucket"); // Retrieves <input type="text" name="description">
    Part filePart = request.getPart("File"); // Retrieves <input type="file" name="file">
    String fileName = filePart.getSubmittedFileName();
    InputStream fileContent = filePart.getInputStream();
    // ... (do your job here)
}*/

public static void uploadFile(String name, String contentType, File file, String bucketName)
      throws IOException, GeneralSecurityException {
    InputStreamContent contentStream = new InputStreamContent(
        contentType, new FileInputStream(file));
    // Setting the length improves upload performance
    contentStream.setLength(file.length());
    StorageObject objectMetadata = new StorageObject()
        // Set the destination object name
        .setName(name)
        // Set the access control list to publicly read-only
        .setAcl(Arrays.asList(
            new ObjectAccessControl().setEntity("allUsers").setRole("READER")));

    // Do the insert
    Storage client = StorageFactory.getService();
    Storage.Objects.Insert insertRequest = client.objects().insert(
        bucketName, objectMetadata, contentStream);

    insertRequest.execute();
  }

}

给我错误的代码是这样的

Storage client = StorageFactory.getService();

我收到的错误信息是

 [ERROR] /home/jy/Desktop/cloud2/example/src/main/java/com/example/upload.java:[50,21]

错误：找不到符号 [错误] -> [帮助 1] org.apache.maven.lifecycle.LifecycleExecutionException: 失败 执行目标 org.apache.maven.plugins:maven-compiler-plugin:2.5.1:compile （默认编译）项目示例：编译失败 /home/jy/Desktop/cloud2/example/src/main/java/com/example/upload.java:[50,21] 错误：找不到符号

  at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:212)

在 org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153) 在 org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145) 在 org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116) 在 org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80) 在 org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51) 在 org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128) 在 org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307) 在 org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193) 在 org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106) 在 org.apache.maven.cli.MavenCli.execute(MavenCli.java:863) 在 org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288) 在 org.apache.maven.cli.MavenCli.main(MavenCli.java:199) 在 sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 在 sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 在 sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 在 java.lang.reflect.Method.invoke(Method.java:606) 在 org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289) 在 org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229) 在 org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415) 在 org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356) 引起：org.apache.maven.plugin.CompilationFailureException： 编译失败 /home/jy/Desktop/cloud2/example/src/main/java/com/example/upload.java:[66,21] 错误：找不到符号

  at org.apache.maven.plugin.AbstractCompilerMojo.execute(AbstractCompilerMojo.java:729)

在 org.apache.maven.plugin.CompilerMojo.execute（CompilerMojo.java:128） 在 org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134) 在 org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:207) ... 20 更多 [ERROR] [ERROR] [ERROR] 错误和可能的解决方案，请阅读以下文章： [错误] [帮助 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

这是我的 pom 文件的样子（非常混乱，因为我只是在尝试代码）：

<properties>
    <appengine.version></appengine.version>
</properties>

<dependencies>
    <!-- Compile/runtime dependencies -->
    <dependency>
        <groupId>com.google.appengine</groupId>
        <artifactId>appengine-api-1.0-sdk</artifactId>
        <version>${appengine.version}</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
    </dependency>

    <dependency>
        <groupId>jstl</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>
    <dependency>
        <groupId>com.google.oauth-client</groupId>
        <artifactId>google-oauth-client-jetty</artifactId>
        <version>1.21.0</version>
    </dependency>
    <!-- Test Dependencies -->
    <dependency>
        <groupId>com.google.appengine</groupId>
        <artifactId>appengine-testing</artifactId>
        <version>${appengine.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.google.appengine</groupId>
        <artifactId>appengine-api-stubs</artifactId>
        <version>${appengine.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.google.apis</groupId>
        <artifactId>google-api-services-storage</artifactId>
        <version>v1-rev65-1.21.0</version>
    </dependency>
    <dependency>
        <groupId>javax</groupId>
        <artifactId>javaee-api</artifactId>
        <version>6.0</version>
    </dependency>
    <dependency>
        <groupId>com.google.gcloud</groupId>
        <artifactId>gcloud-java</artifactId>
        <version>0.1.7</version>
    </dependency>
    <dependency>
        <groupId>com.google.appengine.tools</groupId>
        <artifactId>appengine-gcs-client</artifactId>
        <version>RELEASE</version>
    </dependency>
    <dependency>
        <groupId>com.google.truth</groupId>
        <artifactId>truth</artifactId>
        <version>0.28</version>
        <scope>test</scope>
    </dependency>
</dependencies>

<build>
    <!-- for hot reload of the web application -->
    <outputDirectory>${project.build.directory}/${project.build.finalName}/WEB-INF/classes</outputDirectory>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>versions-maven-plugin</artifactId>
            <version>2.1</version>
            <executions>
                <execution>
                    <phase>compile</phase>
                    <goals>
                        <goal>display-dependency-updates</goal>
                        <goal>display-plugin-updates</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <version>2.5.1</version>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.7</source>
                <target>1.7</target>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-war-plugin</artifactId>
            <version>2.3</version>
            <configuration>
                <archiveClasses>true</archiveClasses>
                <webResources>
                    <!-- in order to interpolate version from pom into appengine-web.xml -->
                    <resource>
                        <directory>${basedir}/src/main/webapp/WEB-INF</directory>
                        <filtering>true</filtering>
                        <targetPath>WEB-INF</targetPath>
                    </resource>
                </webResources>
            </configuration>
        </plugin>

        <plugin>
            <groupId>com.google.appengine</groupId>
            <artifactId>appengine-maven-plugin</artifactId>
            <version>${appengine.version}</version>
            <configuration>
                <enableJarClasses>false</enableJarClasses>
                <version>${app.version}</version>
                <!-- Comment in the below snippet to bind to all IPs instead of just 
                    localhost -->
                <!-- address>0.0.0.0</address> <port>8080</port -->
                <!-- Comment in the below snippet to enable local debugging with a remote 
                    debugger like those included with Eclipse or IntelliJ -->
                <!-- jvmFlags> <jvmFlag>-agentlib:jdwp=transport=dt_socket,address=8000,server=y,suspend=n</jvmFlag> 
                    </jvmFlags -->
            </configuration>
        </plugin>
        <plugin>
            <groupId>com.google.appengine</groupId>
            <artifactId>gcloud-maven-plugin</artifactId>
            <version>${gcloud.plugin.version}</version>
            <configuration>
                <set_default>true</set_default>
            </configuration>
        </plugin>
    </plugins>
</build>

这是我的 Maven 版本

Apache Maven 3.3.9 (bb52d8502b132ec0a5a3f4c09453c07478323dc5; 2015-11-10T08:41:47-08:00) Maven 主页： /home/jy/Desktop/apache-maven-3.3.9 Java 版本：1.7.0_80，供应商： Oracle Corporation Java 主页：/usr/lib/jvm/java-7-oracle/jre 默认 语言环境：en_US，平台编码：UTF-8 操作系统名称：“linux”，版本： “4.2.0-27-generic”，拱：“amd64”，家庭：“unix”

Answer 1

您可能从official GAE sample 复制并粘贴了代码。

您应该查看相关的完整project code on Github。 StorageSample 及其uploadFile 方法提供了类似的代码。

Maven 编译器（以及任何其他编译器/IDE）找不到相关的 StorageFactory 类，因为它不是 GAE 依赖项的一部分，它是作为示例项目的一部分提供的自定义类：StorageFactory .

因此，要编译代码，您应该将其复制到示例项目中。

---

注意：您可能会遇到进一步的编译错误，最好是检查（或克隆）完整的示例项目并从本地工作副本开始。