大数据培训_使用maven工程构建java 的hadoop客户端

工程目录

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​导入Maven的依赖包​

<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>

<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>3.0.0</version>
</dependency>
</dependencies>

packagenet.togogo.hdfs;

importorg.apache.hadoop.conf.Configuration;
importorg.apache.hadoop.fs.FileSystem;
importorg.apache.hadoop.fs.LocatedFileStatus;
importorg.apache.hadoop.fs.Path;
importorg.apache.hadoop.fs.RemoteIterator;
importorg.junit.Before;
importorg.junit.Test;

importjava.io.IOException;
importjava.net.URI;


publicclassHdfsClient{

privateFileSystemfs=null;


@Before
publicvoidinit() {
System.out.println(" init methon start ....");
try{
Configurationconf=newConfiguration();
//连接集群的地址
URIuri=newURI("hdfs://192.168.20.32:9000");
fs=FileSystem.get(uri,conf,"hd");
System.out.println("FileSystem---->"+fs);
} catch(Exceptione) {
e.printStackTrace();
}
System.out.println(" init methon end ....");
}


@Test
publicvoidlistRoot() {
try{
System.out.println("listRoot method ....");
//访问 hadoop fs -ls /
RemoteIterator<LocatedFileStatus>it=fs.listFiles(newPath("/"),true);
//循环
while(it.hasNext()) {
LocatedFileStatuslf=it.next();
System.out.println(lf.getPath().getName());
}
fs.close();
} catch(Exceptione) {
e.printStackTrace();
}
}


@Test
publicvoidmkdir() {
try{

Pathpath=newPath("/test0831");
fs.mkdirs(path);
fs.close();
} catch(IOExceptione) {
e.printStackTrace();
}
}


@Test
publicvoidupload() {
try{
Pathsrc=newPath("F:/hello.log");
Pathdst=newPath("/");
fs.copyFromLocalFile(src,dst);
} catch(IOExceptione) {
e.printStackTrace();
}
}



@Test
publicvoiddownload() {
try{
Pathsrc=newPath("/hello.log");
Pathdst=newPath("F:/dsthello.log");
fs.copyToLocalFile(src,dst);

} catch(IOExceptione) {
e.printStackTrace();
}
}
}