1. 创建文件夹示例
1.1 环境准备
java
hadoop
解压hadoop到本地，配置环境变量
image.png
1.2 新建maven项目
引入依赖：
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>RELEASE</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.2</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>2.7.2</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>2.7.2</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-hdfs</artifactId>
<version>2.7.2</version>
</dependency>
<dependency>
<groupId>jdk.tools</groupId>
<artifactId>jdk.tools</artifactId>
<version>1.8</version>
<scope>system</scope>
<systemPath>C:\SoftWare\Java\jdk1.8.0_211\lib\tools.jar</systemPath>
</dependency>
</dependencies>
编写客户端代码：
@Test
public void testMkdirs() throws IOException, InterruptedException, URISyntaxException {
// 1 获取文件系统
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://192.168.91.129:9000"), configuration, "zl");
// 2 创建目录
fs.mkdirs(new Path("/ff/qq/qq"));
// 3 关闭资源
fs.close();
}
more：
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.*;
import org.junit.Test;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
public class HdfsClient{
/**
* 创建文件夹
* @throws IOException
* @throws InterruptedException
* @throws URISyntaxException
*/
@Test
public void testMkdirs() throws IOException, InterruptedException, URISyntaxException {
// 1 获取文件系统
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://192.168.91.129:9000"), configuration, "zl");
// 2 创建目录
fs.mkdirs(new Path("/ff/qq/qq"));
// 3 关闭资源
fs.close();
}
/**
* 从本地上传文件
* @throws IOException
* @throws InterruptedException
* @throws URISyntaxException
*/
@Test
public void testCopyFromLocalFile() throws IOException, InterruptedException, URISyntaxException {
// 1 获取文件系统
Configuration configuration = new Configuration();
configuration.set("dfs.replication", "2");
FileSystem fs = FileSystem.get(new URI("hdfs://192.168.91.129:9000"), configuration, "zl");
// 2 上传文件
fs.copyFromLocalFile(new Path("C:\\Users\\zl\\Desktop\\banzhang.txt"), new Path("/banzhang.txt"));
// 3 关闭资源
fs.close();
System.out.println("over");
}
/**
* 下载文件到本地
* @throws IOException
* @throws InterruptedException
* @throws URISyntaxException
*/
@Test
public void testCopyToLocalFile() throws IOException, InterruptedException, URISyntaxException{
// 1 获取文件系统
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://192.168.91.129:9000"), configuration, "zl");
// 2 执行下载操作
// boolean delSrc 指是否将原文件删除
// Path src 指要下载的文件路径
// Path dst 指将文件下载到的路径
// boolean useRawLocalFileSystem 是否开启文件校验
fs.copyToLocalFile(false, new Path("/banzhang.txt"), new Path("C:\\Users\\zl\\Desktop\\banzhang2.txt"), true);
// 3 关闭资源
fs.close();
}
/**
* 删除文件夹
* @throws IOException
* @throws InterruptedException
* @throws URISyntaxException
*/
@Test
public void testDelete() throws IOException, InterruptedException, URISyntaxException{
// 1 获取文件系统
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://192.168.91.129:9000"), configuration, "zl");
// 2 执行删除
fs.delete(new Path("/test"), true);
// 3 关闭资源
fs.close();
}
/**
* 重命名文件
* @throws IOException
* @throws InterruptedException
* @throws URISyntaxException
*/
@Test
public void testRename() throws IOException, InterruptedException, URISyntaxException{
// 1 获取文件系统
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://192.168.91.129:9000"), configuration, "zl");
// 2 修改文件名称
fs.rename(new Path("/banzhang.txt"), new Path("/banhua.txt"));
// 3 关闭资源
fs.close();
}
/**
* 列出文件信息
* @throws IOException
* @throws InterruptedException
* @throws URISyntaxException
*/
@Test
public void testListFiles() throws IOException, InterruptedException, URISyntaxException{
// 1获取文件系统
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://192.168.91.129:9000"), configuration, "zl");
// 2 获取文件详情
RemoteIterator<LocatedFileStatus> listFiles = fs.listFiles(new Path("/"), true);
while(listFiles.hasNext()){
LocatedFileStatus status = listFiles.next();
// 输出详情
// 文件名称
System.out.println(status.getPath().getName());
// 长度
System.out.println(status.getLen());
// 权限
System.out.println(status.getPermission());
// 分组
System.out.println(status.getGroup());
// 获取存储的块信息
BlockLocation[] blockLocations = status.getBlockLocations();
for (BlockLocation blockLocation : blockLocations) {
// 获取块存储的主机节点
String[] hosts = blockLocation.getHosts();
for (String host : hosts) {
System.out.println(host);
}
}
System.out.println("-----------分割线----------");
}
// 3 关闭资源
fs.close();
}
/**
* 判断文件是文件还是 文件夹
* @throws IOException
* @throws InterruptedException
* @throws URISyntaxException
*/
@Test
public void testListStatus() throws IOException, InterruptedException, URISyntaxException{
// 1 获取文件配置信息
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://192.168.91.129:9000"), configuration, "zl");
// 2 判断是文件还是文件夹
FileStatus[] listStatus = fs.listStatus(new Path("/"));
for (FileStatus fileStatus : listStatus) {
// 如果是文件
if (fileStatus.isFile()) {
System.out.println("f:"+fileStatus.getPath().getName());
}else {
System.out.println("d:"+fileStatus.getPath().getName());
}
}
// 3 关闭资源
fs.close();
}
}
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