大数据学习记录。二

 1         //查看文件信息
 2         //cathdfs("");
 3         //查看文件内容
 4         //readfile("");
 5         //创建空一个文件
 6         //createfile("");
 7         //创建一个文件并写入文件内容
 8         //cufile("");
 9         //创建一个文件夹
10         //mkdirfile("");
11         //重名称文件或文件夹
12         //renameFile("");
13         //删除文件或文件夹
14         //deletefile("");
15         //上传HDFS
16         //uploadfile("","");
17         //下载到本地
18         //downloadfile("","");

 1 //查询文件信息
 2     public static void cathdfs(String path){
 3         //创建连接uri
 4         String uri="hdfs://192.168.152.131:9000/";
 5         //实例化配置文件对象
 6         Configuration con=new Configuration();
 7         FileSystem fileSystem=null;
 8         FileStatus fileStatus=null;
 9         try {
10             //创建文件系统对象，指定文件的操作
11              fileSystem=FileSystem.get(URI.create(uri),con);
12             //获取单个文件信息系
13               fileStatus=fileSystem.getFileStatus(new Path(path));
14               System.out.print(fileStatus);
15               
16               System.out.print("========================================分割线");
17               /**
18                * 查询所有与文件信息
19                */
20               FileStatus[] listStatus= fileSystem.listStatus(new Path(path));
21               for(FileStatus staus:listStatus){
22                   System.out.println(staus);
23               }
24         } catch (IOException e) {
25             
26             e.printStackTrace();
27         }finally{
28             try {
29                 fileSystem.close();
30             } catch (IOException e) {
31                 e.printStackTrace();
32             }
33         }    
34     
35     }

 1 //查询文件内容
 2     public static void readfile(String fileName){
 3         //第一步创建url链接
 4         String uri="hdfs://192.168.152.131:9000/";
 5         //第二步实例化配置文件对象
 6         Configuration config=new Configuration();
 7         //第三步创建文件系统对象，实现对文件到的操作,创建出入流对象
 8         FileSystem fileSystem=null;
 9         FSDataInputStream input=null;
10         BufferedReader br=null;
11         try {
12             //第四步 使用
13             fileSystem=FileSystem.get(URI.create(uri),config);
14             input=fileSystem.open(new Path(fileName));
15             br=new BufferedReader(new InputStreamReader(input));
16             String line="";
17             while((line=br.readLine())!=null){
18                 System.out.print(line);
19             }
20         } catch (IOException e) {
21             e.printStackTrace();
22         }finally{
23             try {
24                 //第五步关闭资源
25                 br.close();
26                 input.close();
27                 fileSystem.close();
28             } catch (IOException e) {
29                 
30                 e.printStackTrace();
31             }
32         }
33         
34     }

 1 //创建一个空的文件
 2     public static void createfile(String filename){
 3         //一
 4         String uri="hdfs://192.168.152.131:9000/";
 5         //二
 6         Configuration con=new Configuration();
 7         //三
 8         FileSystem file=null;
 9         try {
10              file=FileSystem.get(URI.create(uri),con);
11             boolean fase=file.createNewFile(new Path(filename));
12             if(fase){
13                 System.out.print("成功");
14             }else{
15                 System.out.print("失败");
16             }
17         } catch (IOException e) {
18             
19             e.printStackTrace();
20         }finally{
21             try {
22                 //四
23                 file.close();
24             } catch (IOException e) {
25                 e.printStackTrace();
26             }
27         }
28     }

 1 //创建一个空文件并写入文件
 2     public static void cufile(String filename){
 3         //1
 4         String uri="hdfs://192.168.152.131:9000/";
 5         //2
 6         Configuration con=new Configuration();
 7         //3
 8         FileSystem fiel=null;
 9         FSDataOutputStream fs=null;
10         try {
11              fiel=FileSystem.get(URI.create(uri),con);
12              if(fiel.exists(new Path(filename))){
13                  //文件已经存在
14                 System.out.println("文件已经存在"); 
15              }else{
16                  //文件不存在
17                  fs= fiel.create(new Path(filename));
18                 //文件内容
19                 String str="呵呵";
20                 fs.write(str.getBytes());
21                 fs.flush();
22              }
23         } catch (IOException e) {
24             
25             e.printStackTrace();
26         }finally{
27             try {
28                 //4
29                 fs.close();
30                 fiel.close();
31             } catch (IOException e) {
32                 
33                 e.printStackTrace();
34             }
35         }
36     }

 1 //创建一个文件夹
 2     public static void mkdirfile(String filename){
 3         //1
 4         String uri="hdfs://192.168.152.131:9000/";
 5         //2
 6         Configuration con=new Configuration();
 7         //3
 8         FileSystem file=null;
 9         try {
10             file=FileSystem.get(URI.create(uri),con);
11             boolean mkdirs = file.mkdirs(new Path(filename));
12             if(mkdirs){
13                 System.out.print("成功");
14             }else{
15                 System.out.print("失败");
16             }
17         } catch (IOException e) {
18             
19             e.printStackTrace();
20         }finally{
21             try {
22                 //4    
23                 file.close();
24             } catch (IOException e) {
25                 
26                 e.printStackTrace();
27             }
28         }
29     }
30

 1 //重命名文件或文件夹
 2     public static void renameFile(String oldname,String filename){
 3         //1
 4         String uri="hdfs://192.168.152.131:9000/";
 5         //2
 6         Configuration con=new Configuration();
 7         //3
 8         FileSystem file=null;
 9         try {
10             file=FileSystem.get(URI.create(uri),con);
11             //1.文件或文件夹原名称  2.修改文件或文件夹名称
12             boolean rename = file.rename(new Path(oldname), new Path(filename));
13             if(rename){
14                 System.out.print("成功");
15             }else{
16                 System.out.print("失败");
17             }
18         } catch (IOException e) {
19             
20             e.printStackTrace();
21         }finally{
22             try {
23                 file.close();
24             } catch (IOException e) {
25                 
26                 e.printStackTrace();
27             }
28         }
29         
30     }
31

 1 //删除文件或文件夹
 2     public static void deletefile(String filename){
 3         //1
 4         String uri="hdfs://192.168.152.131:9000/";
 5         //2
 6         Configuration con=new Configuration();
 7         //3
 8         FileSystem file=null;
 9         try {
10             file=FileSystem.get(URI.create(uri),con);
11             boolean delete = file.delete(new Path(filename));
12             if(delete){
13                 System.out.print("成功");
14             }else{
15                 System.out.print("失败");
16             }
17         } catch (IOException e) {
18             
19             e.printStackTrace();
20         }finally{
21             try {
22                 file.close();
23             } catch (IOException e) {
24                 
25                 e.printStackTrace();
26             }
27         }
28     }

 1 //本地文件上传到HDFS
 2     public static void uploadfile(String loadfile,String desfile){
 3         //1
 4         String uri="hdfs://192.168.152.131:9000/";
 5         //2
 6         Configuration con=new Configuration();
 7         //3
 8         FileSystem file=null;
 9         try {
10             file=FileSystem.get(URI.create(uri),con);
11             //上传中
12             file.copyFromLocalFile(new Path(loadfile), new Path(desfile));
13         } catch (IOException e) {
14             
15             e.printStackTrace();
16         }finally{
17             try {
18                 file.close();
19             } catch (IOException e) {
20                 
21                 e.printStackTrace();
22             }
23         }
24         System.out.println("上传中---------");
25     }

 1 //HDFS下载文件到本地
 2     public static void downloadfile(String desfile,String loadfile){
 3         //1
 4         String uri="";
 5         //2
 6         Configuration con=new Configuration();
 7         //3
 8         FileSystem file=null;
 9         try {
10             file=FileSystem.get(URI.create(uri),con);
11             //下载中
12             file.copyToLocalFile(new Path(desfile), new Path(loadfile));
13         } catch (IOException e) {
14             
15             e.printStackTrace();
16         }finally{
17             try {
18                 file.close();
19             } catch (IOException e) {
20                 
21                 e.printStackTrace();
22             }
23         }
24         System.out.println("下载中-----------");
25     }

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工具：eclipse

工程：Maven