1. cd /home/hadoop/app/hadoop/etc/hadoop
    2. vi core-site.xml

    更改core-site.xml文件，插入以下代码

    1.     <!-- 设置用户 -->
    2. <property>
    3.   <name>hadoop.http.staticuser.user</name>
    4.   <value>root</value>
    5. </property>
    6. <!-- 不开启权限检查 -->
    7. <property>
    8.   <name>dfs.permissions.enabled</name>
    9.   <value>false</value>
    10. </property>

    更改完之后就可以通过网页端上传文件了

    1. vi hdfs-site.xml

    插入以下代码

    1. <property>
    2.     <name>dfs.permissions</name>
    3.     <value>false</value>
    4. </property>

    前期准备工作已经完成，打开启动hadoop服务
    先把比做环节完成了
    实验三必完成环节.pdf
    截图发给老师
    image.png
    接下来是选做环节
    实验三选做环节.docx
    按照第二种配置IDEA
    创建MAVEN项目
    image.png
    直接next
    pom.xml文件

    1. import org.apache.hadoop.conf.Configuration;
    2. import org.apache.hadoop.fs.*;
    4. import javax.security.auth.login.AppConfigurationEntry;
    5. import java.io.IOException;
    6. import java.io.PrintStream;
    7. import java.net.URI;
    8. import java.net.URL;
    10. public class demo {
    11. }
    12. class MyPathFilter implements PathFilter{
    13.     String reg = null;
    14.     MyPathFilter(String reg){
    15.         this.reg = reg;
    16.     }
    17.     @Override
    18.     public boolean accept(Path path) {
    19.         if (!(path.toString().matches(reg))){
    20.             return true;
    21.         }
    22.         return false;
    23.     }
    24. }
    25. class MergeFile{
    26.     Path inputPath = null;
    27.     Path outputPath = null;
    28.     public MergeFile(String inputPath,String outputPath){
    29.         this.inputPath = new Path(inputPath);
    30.         this.outputPath = new Path(outputPath);
    31.     }
    32.     public void doMerge() throws IOException{
    33.         Configuration conf = new Configuration();
    34.         conf.set("fs.defaultFS","hdfs://192.168.255.123:9000");
    35.         conf.set("fs.hdfs.impl","org.apache.hadoop.hdfs.DistributedFileSystem");
    36.         FileSystem fsSource = FileSystem.get(URI.create(inputPath.toString()),conf);
    37.         FileSystem fsDst = FileSystem.get(URI.create(outputPath.toString()),conf);
    38.         FileStatus[] sourceStatus = fsSource.listStatus(inputPath,new MyPathFilter(".*\\.abc"));
    39.         FSDataOutputStream fsdos = fsDst.create(outputPath);
    40.         PrintStream ps = new PrintStream(System.out);
    41.         for (FileStatus sta:
    42.              sourceStatus) {
    43.             System.out.println("路径："+sta.getPath()+"文件大小："+sta.getLen()+"权限："+sta.getPermission()+"内容：");
    44.             FSDataInputStream fsdis = fsSource.open(sta.getPath());
    45.             byte[] data = new byte[1024];
    46.             int read = -1;
    47.             while ((read = fsdis.read(data))>0){
    48.                 ps.write(data,0,read);
    49.                 fsdos.write(data,0,read);
    50.             }
    51.             fsdis.close();
    52.         }
    53.         ps.close();
    54.         fsdos.close();
    55.     }
    57.     public static void main(String[] args) throws IOException {
    58.         MergeFile merge = new MergeFile("hdfs://192.168.255.123:9000/user/hadoop","hdfs://192.168.255.123:9000/user/hadoop/merge.txt");
    59.         merge.doMerge();
    60.     }
    61. }

    运行就完了
    image.png
    image.png
    看到有merge.txt文件