HDFS命令所在目錄： /home/hadoop/hadoop-2.7.2/bin 執行命令時需要帶./代表當前目錄： ./hdfs dfs - ls / 查看環境變量$PATH echo $PATH HDFS Shell接口 顯示指定目錄下文件的詳細信息 ~~~ hdfs dfs -ls / hdfs dfs -ls /music ~~~ 創建目錄 ~~~ hdfs dfs -mkdir /music ~~~ 創建多級目錄 ~~~ hdfs dfs -mkdir -p /music/sub ~~~ 上傳文件 ~~~ hdfs dfs -put /home/hadoop/aa.jpg /music hdfs dfs -put /home/hadoop/aa.jpg hdfs://master:9000/music ~~~ 下載文件 ~~~ hdfs dfs -copyToLocal /music/aa.jpg /home/hadoop/copy.jpg ~~~ 復制文件 ~~~ hdfs dfs -cp /music/aa.jpg /music/bb.jpg ~~~ 移動和重命名文件 ~~~ hdfs dfs -mv /home/hadoop/aa.jpg /music/bb.jpg hdfs dfs -mv /home/hadoop/aa.jpg /music/sub/bb.jpg ~~~ 刪除文件 ~~~ hdfs dfs -rm /music/aa.jpg hdfs dfs -rm -r /music/* ~~~ 查看文件內容 ~~~ hdfs dfs -cat /music/test.txt ~~~ 追加內容 ~~~ hdfs dfs -appendToFile README.txt /music/test.txt ~~~ HDFS編程 1. 把master上配置好的集群hadoop-2.7.2導出到``window``中。 在sftp命令下: ~~~ lcd e:/tmp get /home/hadoop/hadoop-2.7.2 ~~~ 2. 把hadoop-eclipse-plugin-2.7.2.jar放到eclipse的plugins目錄下。 在eclipse下配置插件，windows-> show view->other   3. 在eclipse中選擇Windows→Preference按鈕，彈出一個對話框，在該對話框左側會多出一個Hadoop Map/Reduce選項，然后單擊此選項，在右側設置Hadoop的安裝目錄。 4. 創建MapReduce工程 選擇File→Other命令，找到Map/Reduce Project，然后選擇它，如下所示：  5. 創建測試類（上傳文件）， Run As Java Application ~~~ import java.io.IOException; import java.net.URI; import java.net.URISyntaxException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileStatus; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; public class TestHDFS { public static void main(String[] args) throws IOException, InterruptedException, URISyntaxException { Configuration conf = new Configuration(); /*conf.set("fs.defaultFS", "hdfs://192.168.231.4:9000"); FileSystem hdfs = FileSystem.get(conf);*/ FileSystem hdfs = FileSystem.get(new URI("hdfs://192.168.231.4:9000"),conf,"hadoop"); Path src = new Path("e:/xx.txt"); Path dst = new Path("/music/xx.txt"); hdfs.copyFromLocalFile(src, dst); System.out.println("Upload to :"+conf.get("fs.default.name")); FileStatus files[] = hdfs.listStatus(dst); for(FileStatus file:files){ System.out.println(file.getPath()); } } ~~~ 6. 創建測試類（創建文件） ~~~ import java.io.IOException; import java.net.URI; import java.net.URISyntaxException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FSDataOutputStream; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; public class TestHDFS2 { public static void main(String[] args) throws IOException, InterruptedException, URISyntaxException { Configuration conf = new Configuration(); //conf.set("fs.defaultFS", "hdfs://192.168.1.109:9000"); //FileSystem hdfs = FileSystem.get(conf); FileSystem hdfs = FileSystem.get(new URI("hdfs://192.168.231.4:9000"),conf,"hadoop"); byte[] buff = "hello word".getBytes(); Path dst = new Path("/music/hello.txt"); FSDataOutputStream outputStream = hdfs.create(dst); outputStream.write(buff,0,buff.length); outputStream.close(); boolean isExists = hdfs.exists(dst); System.out.println(isExists); } } ~~~ 7. 創建測試類（讀取文件） ~~~ import java.io.IOException; import java.net.URI; import java.net.URISyntaxException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FSDataInputStream; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; public class TestHDFS3 { public static void main(String[] args) throws IOException, InterruptedException, URISyntaxException { Configuration conf = new Configuration(); FileSystem hdfs = FileSystem.get(new URI("hdfs://192.168.231.4:9000"),conf,"hadoop"); FSDataInputStream is = hdfs.open(new Path("/music/xx.txt")); int i = is.read(); while(i != -1) { System.out.print((char)i); i = is.read(); } is.close(); } } ~~~ 8. 創建測試類（查看/music目錄下所有文件） ~~~ import java.io.IOException; import java.net.URI; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileStatus; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; public class TestHDFS4 { public static void main(String[] args) throws IOException, InterruptedException { Configuration conf = new Configuration(); String uri = "hdfs://192.168.231.4:9000"; FileSystem hdfs = FileSystem.get(URI.create(uri),conf,"hadoop"); FileStatus[] status = hdfs.listStatus(new Path("/music")); for(FileStatus sta : status){ System.out.println(sta); } } } ~~~ 9. 創建測試類（刪除文件及目錄） ~~~ import java.io.IOException; import java.net.URI; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; public class TestHDFS5 { public static void main(String[] args) throws IOException, InterruptedException { Configuration conf = new Configuration(); String uri = "hdfs://192.168.231.4:9000"; FileSystem hdfs = FileSystem.get(URI.create(uri),conf,"hadoop"); //Path dst = new Path("/music/aa.jpg"); Path dst = new Path("/music"); boolean isdeleted = hdfs.delete(dst, true); System.out.println(isdeleted); } } ~~~