3.1 用戶端環境準備
1. 根據自己電腦的作業系統拷貝對應的編譯後的hadoop jar包到非中文路徑(例如:D:\Develop\hadoop-2.7.2)
2. 配置HADOOP_HOME環境變量
3. 配置Path環境變量
4. 建立一個Maven工程
5.導入相應的依賴坐标+日志添加
//pom.xml
<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>${JAVA_HOME}/lib/tools.jar</systemPath>
</dependency>
</dependencies>
#log4j.properties
log4j.rootLogger=INFO, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n
log4j.appender.logfile=org.apache.log4j.FileAppender
log4j.appender.logfile.File=target/spring.log
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n
3.2 HDFS的API操作
(1)檔案上傳
public void testCopyFromLocalFile() throws IOException, InterruptedException, URISyntaxException {
// 1 擷取檔案系統
Configuration configuration = new Configuration();
configuration.set("dfs.replication", "2");
FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), configuration, "root");
// 2 上傳檔案
fs.copyFromLocalFile(new Path("e:/test.txt"), new Path("/test.txt"));
// 3 關閉資源
fs.close();
System.out.println("over");
}
參數優先級排序:(1)用戶端代碼中設定的值 >(2)ClassPath下的使用者自定義配置檔案 >(3)然後是伺服器的預設配置
(2)檔案下載下傳
public void testCopyToLocalFile() throws IOException, InterruptedException, URISyntaxException{
// 1 擷取檔案系統
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), configuration, "root");
// 2 執行下載下傳操作
// boolean delSrc 指是否将原檔案删除
// Path src 指要下載下傳的檔案路徑
// Path dst 指将檔案下載下傳到的路徑
// boolean useRawLocalFileSystem 是否開啟檔案校驗
fs.copyToLocalFile(false, new Path("/test.txt"), new Path("e:/test.txt"), true);
// 3 關閉資源
fs.close();
}
(3)建立檔案夾
public void testMkdirs() throws IOException, InterruptedException, URISyntaxException{
// 1 擷取檔案系統
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), configuration, "root");
// 2 建立目錄
fs.mkdirs(new Path("/xlz/20200719"));
// 3 關閉資源
fs.close();
}
(4)删除檔案夾
public void testDelete() throws IOException, InterruptedException, URISyntaxException{
// 1 擷取檔案系統
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), configuration, "root");
// 2 執行删除
fs.delete(new Path("/xlz/20200719"), true);
// 3 關閉資源
fs.close();
}
(5)檔案名更改
public void testRename() throws IOException, InterruptedException, URISyntaxException{
// 1 擷取檔案系統
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), configuration, "root");
// 2 修改檔案名稱
fs.rename(new Path("/test.txt"), new Path("/xlz.txt"));
// 3 關閉資源
fs.close();
}
(6)檔案詳情檢視
public void testListFiles() throws IOException, InterruptedException, URISyntaxException{
// 1擷取檔案系統
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), configuration, "root");
// 2 擷取檔案詳情
RemoteIterator<LocatedFileStatus> listFiles = fs.listFiles(new Path("/"), true);
while(listFiles.hasNext()){
LocatedFileStatus status = listFiles.next();
// 輸出詳情
// 檔案名稱
System.out.println(status.getPath().getName());
// 長度
System.out.println(status.getLen());
// 權限
System.out.println(status.getPermission());
// 分組
System.out.println(status.getGroup());
// 擷取存儲的塊資訊
BlockLocation[] blockLocations = status.getBlockLocations();
for (BlockLocation blockLocation : blockLocations) {
// 擷取塊存儲的主機節點
String[] hosts = blockLocation.getHosts();
for (String host : hosts) {
System.out.println(host);
}
}
System.out.println("-----------分割線----------");
}
// 3 關閉資源
fs.close();
}
(7)檔案和檔案夾判斷
public void testListStatus() throws IOException, InterruptedException, URISyntaxException{
// 1 擷取檔案配置資訊
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), configuration, "root");
// 2 判斷是檔案還是檔案夾
FileStatus[] listStatus = fs.listStatus(new Path("/"));
for (FileStatus fileStatus : listStatus) {
// 如果是檔案
if (fileStatus.isFile()) {
System.out.println("f:"+fileStatus.getPath().getName());
}else {
System.out.println("d:"+fileStatus.getPath().getName());
}
}
// 3 關閉資源
fs.close();
}
3.3 HDFS的I/O流操作
(a)檔案上傳
public void putFileToHDFS() throws IOException, InterruptedException, URISyntaxException {
// 1 擷取檔案系統
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), configuration, "root");
// 2 建立輸入流
FileInputStream fis = new FileInputStream(new File("e:/upload.txt"));
// 3 擷取輸出流
FSDataOutputStream fos = fs.create(new Path("/upload.txt"));
// 4 流對拷
IOUtils.copyBytes(fis, fos, configuration);
// 5 關閉資源
IOUtils.closeStream(fos);
IOUtils.closeStream(fis);
fs.close();
}
(b)檔案下載下傳
public void getFileFromHDFS() throws IOException, InterruptedException, URISyntaxException{
// 1 擷取檔案系統
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), configuration, "root");
// 2 擷取輸入流
FSDataInputStream fis = fs.open(new Path("/upload.txt"));
// 3 擷取輸出流
FileOutputStream fos = new FileOutputStream(new File("e:/download.txt"));
// 4 流的對拷
IOUtils.copyBytes(fis, fos, configuration);
// 5 關閉資源
IOUtils.closeStream(fos);
IOUtils.closeStream(fis);
fs.close();
}
(c)定位檔案讀取
//下載下傳檔案第1塊
public void readFileSeek1() throws IOException, InterruptedException, URISyntaxException{
// 1 擷取檔案系統
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), configuration, "root");
// 2 擷取輸入流
FSDataInputStream fis = fs.open(new Path("/hadoop-2.7.2.tar.gz"));
// 3 建立輸出流
FileOutputStream fos = new FileOutputStream(new File("e:/hadoop-2.7.2.tar.gz.part1"));
// 4 流的拷貝
byte[] buf = new byte[1024];
for(int i =0 ; i < 1024 * 128; i++){
fis.read(buf);
fos.write(buf);
}
// 5關閉資源
IOUtils.closeStream(fis);
IOUtils.closeStream(fos);
fs.close();
}
//下載下傳檔案第2塊
public void readFileSeek2() throws IOException, InterruptedException, URISyntaxException{
// 1 擷取檔案系統
Configuration configuration = new Configuration();
FileSystem fs = FileSystem.get(new URI("hdfs://hadoop01:9000"), configuration, "root");
// 2 打開輸入流
FSDataInputStream fis = fs.open(new Path("/hadoop-2.7.2.tar.gz"));
// 3 定位輸入資料位置
fis.seek(1024*1024*128);
// 4 建立輸出流
FileOutputStream fos = new FileOutputStream(new File("e:/hadoop-2.7.2.tar.gz.part2"));
// 5 流的對拷
IOUtils.copyBytes(fis, fos, configuration);
// 6 關閉資源
IOUtils.closeStream(fis);
IOUtils.closeStream(fos);
}
合并檔案:
在Window指令視窗中進入到目錄E:\,然後執行如下指令,對資料進行合并;
type hadoop-2.7.2.tar.gz.part2 >> hadoop-2.7.2.tar.gz.part1;
合并完成後,将hadoop-2.7.2.tar.gz.part1重新命名為hadoop-2.7.2.tar.gz;
解壓發現該tar包非常完整。