UGI连接hive客户端的java代码

以下是使用UGI连接Hive客户端的Java代码示例：

import java.io.IOException;
import java.security.PrivilegedExceptionAction;
import java.util.List;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.security.authentication.util.KerberosName;
import org.apache.hadoop.security.token.Token;
import org.apache.hadoop.security.token.TokenIdentifier;
import org.apache.hadoop.security.token.TokenSelector;
import org.apache.hadoop.security.token.delegation.AbstractDelegationTokenSelector;
import org.apache.hadoop.security.token.delegation.AbstractDelegationTokenSecretManager;
import org.apache.hadoop.security.token.delegation.DelegationKey;
import org.apache.hadoop.security.token.delegation.ZKDelegationTokenSecretManager;
import org.apache.hadoop.security.token.delegation.ZKDelegationTokenSecretManager.ZKDTSMState;
import org.apache.hadoop.security.token.delegation.web.DelegationTokenIdentifier;
import org.apache.hadoop.security.token.delegation.web.DelegationTokenManager;
import org.apache.hadoop.security.token.delegation.web.DelegationTokenManager.HttpUserGroupInformation;
import org.apache.hadoop.security.token.delegation.web.DelegationTokenManager.KerberosDelegationTokenAuthenticator;
import org.apache.hadoop.security.token.delegation.web.DelegationTokenManager.ZKDTSMKeyOp;
import org.apache.hadoop.security.token.delegation.web.DelegationTokenManager.ZKSecretManagerState;
import org.apache.hadoop.security.token.delegation.web.ZKDelegationTokenSecretManagerForTest;
import org.apache.hadoop.security.token.delegation.web.ZKDelegationTokenSecretManagerForTest.ZKDTSMForTestState;
import org.apache.hadoop.security.token.delegation.web.ZKDelegationTokenSecretManagerForTest.ZKDelegationTokenSecretManagerForTestImpl;
import org.apache.hadoop.security.token.delegation.web.ZKDelegationTokenSecretManagerForTest.ZKDelegationTokenSecretManagerForTestState;
import org.apache.hadoop.util.StringUtils;

import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.metastore.HiveMetaStoreClient;

public class HiveClientWithUGI {
  public static void main(String[] args) throws Exception {
    final String user = "hiveuser";
    final String keytabLocation = "/path/to/user.keytab";
    final String krb5Location = "/path/to/krb5.conf";

    // Set Hadoop and Hive configurations
    Configuration conf = new Configuration();
    conf.set("hadoop.security.authentication", "Kerberos");
    conf.set("hadoop.security.authorization", "true");
    conf.set("hive.metastore.sasl.enabled", "true");
    conf.set("hive.metastore.kerberos.principal", "hive/_HOST@EXAMPLE.COM");
    conf.set("hive.metastore.sasl.qop", "auth-conf");
    conf.set("hive.metastore.client.factory.class", "org.apache.hadoop.hive.metastore.hbase.HBaseMetaStoreClientFactory");

    // Set Kerberos security
    System.setProperty("java.security.krb5.conf", krb5Location);
    UserGroupInformation.setConfiguration(conf);
    UserGroupInformation.loginUserFromKeytab(user, keytabLocation);

    // Create a Hive metastore client
    HiveConf hiveConf = new HiveConf(conf, HiveConf.class);
    HiveMetaStoreClient hiveClient = new HiveMetaStoreClient(hiveConf);

    // Get list of databases
    List<String> databases = hiveClient.getAllDatabases();
    for (String database : databases) {
      System.out.println(database);
    }

    // Close the client
    hiveClient.close();
  }
}

需要注意的是，代码中涉及到了Kerberos认证和安全配置，需要根据实际情况进行调整。同时，需要根据实际的Hive Metastore服务地址和端口进行设置。此外，代码中使用了UGI来进行Kerberos认证，需要提供对应的keytab文件和krb5.conf文件。