启动Hadoop

cd / -name hadoop
sbin/start-all.sh
jps
bin/hadoop dfsadmin -report

初始化：bin/hadoop namenod -format
集群启动：sbin/start-all.sh
集群停止：sbin/stop-all.sh
查看日志：ll logs/
   cat logs/hadoop-hadoop-namenode-master.log

查看HDFS的命令：hadoop fs

Hadoop fs -ls
   -mkdir
   -copyFromLocal newtest  /home/user
   -put /home/user  /user/hadoop
   -copyToLocal /user/hadoop /home/hadoop
   -get /user/hadoop /home/user
   -chmod 777 /user/hadoop
   -rm  -r text

负载均衡：hdfs balancer

hdfs balancer -threshold 
```	  

### HDFS API使用方法
1.get（）方法实现
 static FileSystem get(Configuration conf);
2.获取具体的封装
 	opertor(){
  获取Configuration对象
  获取FileSystem对象
  对文件进行相应操作
 }
###	1.上传本地文件：
  具体实现：CopyFile.jar
    package com.hafs;
    import org.apache.hadoop.conf.Configuration;
    import org.apache.hadoop.fs.FileStatus;
    import org.apache.hadoop.fs.FileSystem;
    impory org.apache.hadoop.fs.Path;
    public class CopyFile{
        public static void main(String[] args) throws Excerion{
            Configuration conf = new Configuration();
            FileSystemhdfs = FileSystem.get(conf);
            //本地文件
            Path src = new Path("/home/hadoop/CopyFile.text");
            //HDFS的指定位置
            Path dst = new Path("/");
            hdfs.copyFromLocalFile(src,dst);
            System.out.print("Upload to"+conf.get("fs.default.name"));
            FileStatus files[] = hdfs.listStatus(dst);
            for(FileStstus file:files){
                System.out.print(file.getPath());
            }
        }
    }

  导出为CopyFile.jar文件，上传到集群中并文件所在位置执行命令：
```		
   Hadoop jar CopyFile.jar com.hdfs.CopyFile

2.创建HDFS文件

    Public FSDateOutputStream create (Path f)

    具体实现：CreateFile.jar

Package com.hdfs;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSysteam;
import org.apache.hadoop.fs.Path;
public class CreateFile{
 public static void main (String[] args) throws Exception{
  Configuration conf = new Configuration();
  FileSysteamhdfs = FileSyteam.get(conf);
   byte[] buff = "hello hadoop world!\n".getByets();
   Path dfs = new Path("/test");
   FSDataOutputStream outputStream = hdfs.create(dfs);//调用create（）方法，创建文件
   outputStream.write(buff,0,buff.length);
  }
 }
    导出为CreatFile.jar文件，上传到集群中并文件所在位置执行命令：

hadoop jar CreateFile.jar comhdfs.CreateFile

3.创建HDFS目录

    public boolean mkdirs(Path f)

    具体实现：CreateDir.jar

package com.hdfs;
import org.apache.hadoop.conf.Configuration;
improt org.apache.hadoop.fs.FileSysteam;
import org.apache.hadoop.fs.Path;
public class CreateDir{
 public static void main (String[] args) throws Exception{
  Configuration conf = new Configuration();
  FileSyateamhdfs = FileSyateam.get(conf);
  Path dfs = new Path("/TestDir");
  //调用mkdir（）方法，创建目录
  hdfs.mkdirs(dfs);
 }
}
    导出CreateDir.jar文件，上传到集群中并文件所在位置执行命令：

hadoop jar CreateDir.jar com.hdfs.CreateDir;