大数据学习——java操作hdfs环境搭建以及环境测试

1 新建一个maven项目

打印根目录下的文件的名字

添加pom依赖

pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<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.cyf</groupId>
  <artifactId>hdfstest</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>hdfstest Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <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>
  </properties>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.9</version>
    </dependency>
    <dependency>
      <groupId>org.apache.hadoop</groupId>
      <artifactId>hadoop-common</artifactId>
      <version>2.6.4</version>
    </dependency>
    <dependency>
      <groupId>org.apache.hadoop</groupId>
      <artifactId>hadoop-hdfs</artifactId>
      <version>2.6.4</version>
    </dependency>
    <dependency>
      <groupId>org.apache.hadoop</groupId>
      <artifactId>hadoop-client</artifactId>
      <version>2.6.4</version>
    </dependency>
  </dependencies>
</project>

2 测试

TestHDFS.java

package cn.itcast.hdfs;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocatedFileStatus;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.RemoteIterator;

public class TestHDFS {
    public static void main(String[] args) throws IOException {
        Configuration conf = new Configuration();
        //1首先需要一个hdfs的客户端对象
        conf.set("fs.defaultFS", "hdfs://mini1:9000");
        FileSystem fs = FileSystem.get(conf);
        RemoteIterator<LocatedFileStatus> listFiles = fs.listFiles(new Path("/"), false);
        //通过迭代器可以遍历出我们hdfs文件系统的根目录下的文件
        while (listFiles.hasNext()) {
            LocatedFileStatus fileStatus = listFiles.next();
            Path path = fileStatus.getPath();

            String fileName = path.getName();
            System.out.println(fileName);
        }

    }
}

运行结果如下图