只需编写一个简单的java程序，并像普通的.jar文件一样运行它。
在项目中，您需要导入hadoop库。
这是一个maven项目的工作示例（我在集群上测试了它）：

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;

public class WriteFileToHdfs {

    public static void main(String[] args) throws IOException, URISyntaxException {

        String dataNameLocation = "hdfs://[your-namenode-ip]:[the-port-where-hadoop-is-listening]/";

        Configuration configuration = new Configuration();
        FileSystem hdfs = FileSystem.get( new URI( dataNameLocation ), configuration );
        Path file = new Path(dataNameLocation+"/myFile.txt");

        FSDataOutputStream out = hdfs.create(file);
        out.writeUTF("Some text ...");
        out.close();

        hdfs.close();

    }

}

请记住将依赖项放在pom.xml中，以及为主类构建清单文件的说明：

<properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
        <mainClass>your.cool.package.WriteFileToHdfs</mainClass>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-client</artifactId>
            <version>2.6.1</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>            
          <plugin>
            <artifactId>maven-dependency-plugin</artifactId>
            <executions>
                <execution>
                    <phase>install</phase>
                    <goals>
                        <goal>copy-dependencies</goal>
                    </goals>
                    <configuration>
                        <outputDirectory>${project.build.directory}/lib</outputDirectory>
                    </configuration>
                </execution>
            </executions>
        </plugin>
        <plugin>
            <artifactId>maven-jar-plugin</artifactId>
            <configuration>
                <archive>
                    <manifest>
                        <addClasspath>true</addClasspath>
                        <classpathPrefix>lib/</classpathPrefix>
                        <mainClass>${mainClass}</mainClass>
                    </manifest>
                </archive>
            </configuration>
        </plugin>
      </plugins>
    </build>

只需在程序中使用以下命令：
java-jar名称jarfile.jar
当然，您需要使用包名和namenode ip地址编辑代码。