需要的jar包在hadoop里都可以找到，下面的例子中，至少需要这些jar包：
commons-cli-1.2.jar commons-collections-3.2.1.jar commons-configuration-1.6.jar commons-io-2.4.jar commons-lang-2.6.jar commons-logging-1.1.3.jar guava-11.0.2.jar hadoop-auth-2.7.1.jar hadoop-common-2.7.1.jar hadoop-hdfs-2.7.1.jar htrace-core-3.1.0-incubating.jar log4j-1.2.17.jar protobuf-java-2.5.0.jar servlet-api.jar slf4j-api-1.7.10.jar slf4j-log4j12-1.7.10.jar
代码如下：
package com.neohope.hadoop.test;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
public class HDFSTest {
static Configuration hdfsConfig;
static {
hdfsConfig = new Configuration();
hdfsConfig.addResource(new Path("etc/hadoop/core-site.xml"));
hdfsConfig.addResource(new Path("etc/hadoop/hdfs-site.xml"));
}
// 创建文件夹
public static void createDirectory(String dirPath) throws IOException {
FileSystem fs = FileSystem.get(hdfsConfig);
Path p = new Path(dirPath);
try {
fs.mkdirs(p);
} finally {
fs.close();
}
}
// 删除文件夹
public static void deleteDirectory(String dirPath) throws IOException {
FileSystem fs = FileSystem.get(hdfsConfig);
Path p = new Path(dirPath);
try {
fs.deleteOnExit(p);
} finally {
fs.close();
}
}
// 重命名文件夹
public static void renameDirectory(String oldDirPath, String newDirPath)
throws IOException {
renameFile(oldDirPath, newDirPath);
}
// 枚举文件
public static void listFiles(String dirPath) throws IOException {
FileSystem hdfs = FileSystem.get(hdfsConfig);
Path listf = new Path(dirPath);
try {
FileStatus statuslist[] = hdfs.listStatus(listf);
for (FileStatus status : statuslist) {
System.out.println(status.getPath().toString());
}
} finally {
hdfs.close();
}
}
// 新建文件
public static void createFile(String filePath) throws IOException {
FileSystem fs = FileSystem.get(hdfsConfig);
Path p = new Path(filePath);
try {
fs.createNewFile(p);
} finally {
fs.close();
}
}
// 删除文件
public static void deleteFile(String filePath) throws IOException {
FileSystem fs = FileSystem.get(hdfsConfig);
Path p = new Path(filePath);
try {
fs.deleteOnExit(p);
} finally {
fs.close();
}
}
// 重命名文件
public static void renameFile(String oldFilePath, String newFilePath)
throws IOException {
FileSystem fs = FileSystem.get(hdfsConfig);
Path oldPath = new Path(oldFilePath);
Path newPath = new Path(newFilePath);
try {
fs.rename(oldPath, newPath);
} finally {
fs.close();
}
}
// 上传文件
public static void putFile(String locaPath, String hdfsPath)
throws IOException {
FileSystem fs = FileSystem.get(hdfsConfig);
Path src = new Path(locaPath);
Path dst = new Path(hdfsPath);
try {
fs.copyFromLocalFile(src, dst);
} finally {
fs.close();
}
}
// 取回文件
public static void getFile(String hdfsPath, String locaPath)
throws IOException {
FileSystem fs = FileSystem.get(hdfsConfig);
Path src = new Path(hdfsPath);
Path dst = new Path(locaPath);
try {
fs.copyToLocalFile(false, src, dst, true);
} finally {
fs.close();
}
}
// 读取文件
public static void readFile(String hdfsPath) throws IOException {
FileSystem hdfs = FileSystem.get(hdfsConfig);
Path filePath = new Path(hdfsPath);
InputStream in = null;
BufferedReader buff = null;
try {
in = hdfs.open(filePath);
buff = new BufferedReader(new InputStreamReader(in));
String str = null;
while ((str = buff.readLine()) != null) {
System.out.println(str);
}
} finally {
buff.close();
in.close();
hdfs.close();
}
}
public static void main(String[] args) throws IOException {
System.setProperty("HADOOP_USER_NAME", "hadoop");
// createDirectory("hdfs://hadoop-master:9000/usr");
// createDirectory("hdfs://hadoop-master:9000/usr/hansen");
// createDirectory("hdfs://hadoop-master:9000/usr/hansen/test");
// renameDirectory("hdfs://hadoop-master:9000/usr/hansen/test","hdfs://hadoop-master:9000/usr/hansen/test01");
// createFile("hdfs://hadoop-master:9000/usr/hansen/test01/hello.txt");
// renameFile("hdfs://hadoop-master:9000/usr/hansen/test01/hello.txt","hdfs://hadoop-master:9000/usr/hansen/test01/hello01.txt");
// putFile("hello.txt","hdfs://hadoop-master:9000/usr/hansen/test01/hello02.txt");
// getFile("hdfs://hadoop-master:9000/usr/hansen/test01/hello02.txt","hello02.txt");
// readFile("hdfs://hadoop-master:9000/usr/hansen/test01/hello02.txt");
listFiles("hdfs://hadoop-master:9000/usr/hansen/test01/");
}
}