云pubsub pom.xml错误

Question

pom.xml条目：

`<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>com.test.df</groupId>
  <artifactId>dftest</artifactId>
  <version>0.0.1-SNAPSHOT</version>

  <build>
   <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.3</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
    </plugins>

    <pluginManagement>
      <plugins>
        <plugin>
          <groupId>org.codehaus.mojo</groupId>
          <artifactId>exec-maven-plugin</artifactId>
          <version>1.4.0</version>
          <configuration>
            <cleanupDaemonThreads>false</cleanupDaemonThreads>
          </configuration>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>

  <dependencies>
    <dependency>
      <groupId>com.google.cloud.dataflow</groupId>
      <artifactId>google-cloud-dataflow-java-sdk-all</artifactId>
      <version>[1.0.0, 1.9.0)</version>
    </dependency>

        <dependency>
    <groupId>com.google.cloud</groupId>
    <artifactId>google-cloud-pubsub</artifactId>
    <version>0.9.4-alpha</version>
</dependency>

    <!-- slf4j API frontend binding with JUL backend -->
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>1.7.7</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-jdk14</artifactId>
      <version>1.7.7</version>
    </dependency>
    <dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.0</version>
</dependency>
<dependency>
  <groupId>com.google.http-client</groupId>
  <artifactId>google-http-client</artifactId>
  <version>1.17.0-rc</version>
</dependency>
<dependency>
    <groupId>org.json</groupId>
    <artifactId>json</artifactId>
    <version>20090211</version>
</dependency>
<dependency>
    <groupId>com.googlecode.json-simple</groupId>
    <artifactId>json-simple</artifactId>
    <version>1.1</version>
</dependency>
<dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
    </dependency>
  </dependencies>
</project>`

详细说明： 编译时出错： 缺少工件com.google.api-client：google-api-client-jackson2：jar：1.22.0 pom.xml / dftest第1行Maven依赖问题

我正在尝试编写自定义发布者以将消息发送到Cloud PubSub