idea+Hadoop 增删改查20220614
1、window hadoop 安装
2、hadoop 配置
注dfs.permissions.enabled =false 权限放开
3、hadoop 启动
4、Idea+hadoop
1)、pom.xml
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.13.3</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>3.2.1</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>3.2.1</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-hdfs</artifactId>
<version>2.5.2</version>
</dependency>
2)、增删改查询实例
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.*;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.URI;
public class HadoopClients {
static FileSystem fileSystem = null;
public static void main(String[] args) throws Exception {
//mkdir();
//mv();
/* rm();*/
up();
/*see();*/
//readWrite();
}
//静态代码块
static {
Configuration conf = new Configuration();
//hadoop的链接对象
try {
fileSystem = FileSystem.get(new URI(“hdfs://127.0.0.1:9000″),conf,”root”);
} catch (Exception e) {
e.printStackTrace();
}
}
//创建目录
public static void mkdir() throws Exception{
fileSystem.mkdirs(new Path(“/test3”));
System.out.println(“创建成功！！”);
}
//修改目录
public static void mv() throws Exception{
fileSystem.rename(new Path(“/test1”),new Path(“/test2”));
System.out.println(“修改成功！！”);
}
//删除目录
public static void rm() throws Exception{
fileSystem.delete(new Path(“/test2”),true);
System.out.println(“删除成功！！”);
}
//上传数据
public static void up() throws Exception{
fileSystem.copyFromLocalFile(new Path(“c:\\aa.txt”),new Path(“/test2”));
System.out.println(“上传成功！！”);
}
//查看目录
public static void see() throws Exception{
RemoteIterator<LocatedFileStatus> iterator = fileSystem.listFiles(new Path(“/”), true);
//迭代器取数据
while (iterator.hasNext()){
LocatedFileStatus next = iterator.next();
System.out.println(next.getPath());
System.out.println(next.getLen());
System.out.println(next.getBlockSize());
System.out.println(next.getReplication());
System.out.println(“————————————-“);
}
}
}
https://www.cnblogs.com/geeksongs/p/14204767.html