本文实例为大家分享了java代码对hdfs进行增删改查操作的具体代码，供大家参考，具体内容如下
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import java.io.file;
import java.io.fileoutputstream;
import java.io.ioexception;
import java.net.uri;
import org.apache.commons.compress.utils.ioutils;
import org.apache.hadoop.conf.configuration;
import org.apache.hadoop.fs.blocklocation;
import org.apache.hadoop.fs.fsdatainputstream;
import org.apache.hadoop.fs.fsdataoutputstream;
import org.apache.hadoop.fs.filestatus;
import org.apache.hadoop.fs.filesystem;
import org.apache.hadoop.fs.path;
public class fileopreation {
public static void main(string[] args) throws ioexception {
//createfile();
//deletefile();
//copyfiletohdfs();
//mkdirs();
//deldirs();
listdirectory();
download();
}
public static void createfile() throws ioexception {
string uri = "hdfs://alvis:9000";
configuration configuration =new configuration();
filesystem fsystem = filesystem.get(uri.create(uri), configuration);
byte[] file_content_buff="hello hadoop world, test write file !\n".getbytes();
path dfs = new path("/home/test.txt");
fsdataoutputstream outputstream = fsystem.create(dfs);
outputstream.write(file_content_buff.length);
}
public fileopreation() {
// todo auto-generated constructor stub
}public static void deletefile() throws ioexception {
string uri = "hdfs://alvis:9000";
configuration configuration =new configuration();
filesystem fsystem = filesystem.get(uri.create(uri), configuration);
path deletf = new path("/home/test.txt");
boolean delresult = fsystem.delete(deletf,true);
system.out.println(delresult==true?"删除成功":"删除失败");
}
public static void copyfiletohdfs() throws ioexception {
string uri = "hdfs://alvis:9000";
configuration configuration =new configuration();
filesystem fsystem = filesystem.get(uri.create(uri), configuration);
path src = new path("e:\\serializationtest\\apitest.txt");
path dest_src = new path("/home");
fsystem.copyfromlocalfile(src, dest_src);
}
public static void mkdirs() throws ioexception {
string uri = "hdfs://alvis:9000";
configuration configuration =new configuration();
filesystem fsystem = filesystem.get(uri.create(uri), configuration);
path src = new path("/test");
fsystem.mkdirs(src);
}
public static void deldirs() throws ioexception {
string uri = "hdfs://alvis:9000";
configuration configuration = new configuration();
filesystem fsystem = filesystem.get(uri.create(uri), configuration);
path src = new path("/test");
fsystem.delete(src);
}
public static void listdirectory() throws ioexception {
string uri = "hdfs://alvis:9000";
configuration configuration = new configuration();
filesystem fsystem = filesystem.get(uri.create(uri), configuration);
filestatus[] fstatus = fsystem.liststatus(new path("/output"));
for(filestatus status : fstatus)
if (status.isfile()) {
system.out.println("文件路径："+status.getpath().tostring());
system.out.println("文件路径 getreplication："+status.getreplication());
system.out.println("文件路径 getblocksize:"+status.getblocksize());
blocklocation[] blocklocations = fsystem.getfileblocklocations(status, 0, status.getblocksize());
for(blocklocation location : blocklocations){
system.out.println("主机名："+location.gethosts()[0]);
system.out.println("主机名："+location.getnames()[0]);
}
}
else {
system.out.println("directory:"+status.getpath().tostring());
}
}
public static void download() throws ioexception {
configuration configuration = new configuration();
configuration.set("fs.defaultfs", "hdfs://alvis:9000");
filesystem fsystem =filesystem.get(configuration);
fsdatainputstream inputstream =fsystem.open( new path("/input/wc.jar"));
fileoutputstream outputstream = new fileoutputstream(new file("e:\\learnlife\\download\\wc.jar"));
ioutils.copy(inputstream, outputstream);
system.out.println("下载成功！");
}
}
思想：
一、定义虚拟机接口
二、先拿到hdfs远程调用接口对象configuration
三、定义分布式文件系统filesystem对象获取对象
四、给定路径
五、用filesystem对象调用操作
以上所述是小编给大家介绍的java代码对hdfs进行增删改查操作详解整合，希望对大家有所帮助
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