impala（05）——impala的java开发

遵循java开发的一般套路，先导入jar包，来实现通过java代码来进行操作impala的查询。

导入jar包

  <repositories>
        <repository>
            <id>cloudera</id>
            <url>https://repository.cloudera.com/artifactory/cloudera-repos/</url>
        </repository>
        <repository>
            <id>central</id>
            <url>http://repo1.maven.org/maven2/</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>



    <dependencies>
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-common</artifactId>
            <version>2.6.0-cdh5.14.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.hive</groupId>
            <artifactId>hive-common</artifactId>
            <version>1.1.0-cdh5.14.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.hive</groupId>
            <artifactId>hive-metastore</artifactId>
            <version>1.1.0-cdh5.14.0</version>
        </dependency>

        <dependency>
            <groupId>org.apache.hive</groupId>
            <artifactId>hive-service</artifactId>
            <version>1.1.0-cdh5.14.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.hive</groupId>
            <artifactId>hive-jdbc</artifactId>
            <version>1.1.0-cdh5.14.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.hive</groupId>
            <artifactId>hive-exec</artifactId>
            <version>1.1.0-cdh5.14.0</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.apache.thrift/libfb303 -->
        <dependency>
            <groupId>org.apache.thrift</groupId>
            <artifactId>libfb303</artifactId>
            <version>0.9.0</version>
            <type>pom</type>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.apache.thrift/libthrift -->
        <dependency>
            <groupId>org.apache.thrift</groupId>
            <artifactId>libthrift</artifactId>
            <version>0.9.0</version>
            <type>pom</type>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.2.5</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpcore -->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
            <version>4.2.5</version>
        </dependency>

    </dependencies>

java代码查询开发

public class ImpalaDemo {
    public static void main(String[] args) throws Exception {
    //定义连接驱动类，以及连接url和执行的sql语句
    String driver = "org.apache.hive.jdbc.HiveDriver";
    String driverUrl = "jdbc:hive2://192.168.52.120:21050/mydb1;auth=noSasl";
    String sql = "select * from student";

    //通过反射加载数据库连接驱动
    Class.forName(driver);
    Connection connection = DriverManager.getConnection(driverUrl);
    PreparedStatement preparedStatement = connection.prepareStatement(sql);
    ResultSet resultSet = preparedStatement.executeQuery();
    //通过查询，得到数据一共有多少列
    int col = resultSet.getMetaData().getColumnCount();
    //遍历结果集
    while (resultSet.next()){
        for(int i=1;i<=col;i++){
            System.out.print(resultSet.getString(i)+"\t");
        }
        System.out.print("\n");
    }
    preparedStatement.close();
    connection.close();
}
}