Java 代码本地设置Hadoop用户名密码的方法

<dependencies>  
    <dependency>  
        <groupId>org.apache.hadoop</groupId>  
        <artifactId>hadoop-client</artifactId>  
        <version>3.3.1</version>  
    </dependency>  
</dependencies>

import org.apache.hadoop.conf.Configuration;  
import org.apache.hadoop.fs.FileSystem;  
import org.apache.hadoop.fs.Path;  
import org.apache.hadoop.security.UserGroupInformation;  
import java.io.IOException;  
public class HadoopUserSetup {  
    public static void main(String[] args) {  
        String hdfsUri = "hdfs://localhost:9000";  
        String username = "hadoopuser";  
        String password = "hadooppassword";  
        Configuration conf = new Configuration();  
        conf.set("fs.defaultFS", hdfsUri);  
        conf.set("dfs.client.use.datanode.hostname", "true");  
        UserGroupInformation.setConfiguration(conf);  
        try {  
            UserGroupInformation.loginUserFromKeytab(username, "/path/to/keytab/file.keytab");  
            // 如果不使用Kerberos，可以使用以下方式（不推荐，仅适用于测试环境）  
            // UserGroupInformation ugi = UserGroupInformation.createRemoteUser(username);  
            // ugi.doAs(new PrivilegedExceptionAction<Void>() {  
            //     public Void run() throws Exception {  
            //         FileSystem fs = FileSystem.get(conf);  
            //         // 进行文件操作  
            //         return null;  
            //     }  
            // });  
            FileSystem fs = FileSystem.get(conf);  
            Path path = new Path("/user/hadoopuser/testfile.txt");  
            if (fs.exists(path)) {  
                System.out.println("File exists");  
            } else {  
                System.out.println("File does not exist");  
            }  
            fs.close();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }  
    }  
}

import org.apache.hadoop.conf.Configuration;  
import org.apache.hadoop.fs.FileSystem;  
import org.apache.hadoop.fs.Path;  
import org.apache.hadoop.security.UserGroupInformation;  
import java.io.IOException;  
public class KerberosHdfsConnection {  
    public static void main(String[] args) {  
        String hdfsUri = "hdfs://your-hadoop-cluster:8020"; // 替换为你的HDFS URI  
        String principal = "your-principal@YOUR.REALM"; // 替换为你的Kerberos主体  
        String keytabPath = "/path/to/your.keytab"; // 替换为你的keytab文件路径  
        Configuration conf = new Configuration();  
        conf.set("fs.defaultFS", hdfsUri);  
        conf.set("dfs.client.use.datanode.hostname", "true");  
        conf.set("hadoop.security.authentication", "kerberos");  
        UserGroupInformation.setConfiguration(conf);  
        try {  
            UserGroupInformation.loginUserFromKeytab(principal, keytabPath);  
            FileSystem fs = FileSystem.get(conf);  
            Path path = new Path("/user/your-username/testfile.txt"); // 替换为你的HDFS路径  
            if (fs.exists(path)) {  
                System.out.println("File exists");  
            } else {  
                System.out.println("File does not exist");  
            }  
            fs.close();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }  
    }  
}