Lindorm:Connect to LindormTable with the Cassandra CQL Java driver

Prerequisites

• Java Development Kit (JDK) 1.8 or later is installed.

• The Cassandra CQL Java driver is installed. Install the Cassandra CQL Driver.

• Your client IP address is added to the Lindorm instance whitelist. Configure a whitelist.

• You have obtained the CQL Connection endpoint. In the Lindorm console, go to instance details > Endpoints > LindormTable tab > Cassandra-compatible address to get the private or public address (default username and password: root). View endpoints.

Procedure

1. Configure the connection parameters.

    String[] contactPoints = new String[]{
         "<host>"
    };
    Cluster

   Note

   • host: The CQL Connection address from the Lindorm console. Example: ld-bp17j28j2y7pm****-proxy-lindorm.lindorm.rds.aliyuncs.com.

   • username: The Lindorm instance account name. Default: root.

   • password: The Lindorm instance account password. If forgotten, reset it in the Cluster Management System of LindormTable. Change user password.

2. Use the Cassandra CQL Java API to access Lindorm wide tables.

   • DDL operations

      // Create a keyspace and specify its strategy and replication factor.
         session.execute(
                     "CREATE KEYSPACE IF NOT EXISTS testKeyspace WITH replication "
                             + "= {'class':'SimpleStrategy', 'replication_factor':1};");
      // Create a table and specify its primary key, cluster key, and regular key.
         session.execute(
                     "CREATE TABLE IF NOT EXISTS testKeyspace.testTable ("
                             + "id int PRIMARY KEY,"
                             + "name text,"
                             + "age int,"
                             + "address text"
                             + ");");    
      // Truncate the table.
         session.execute("TRUNCATE TABLE testKeyspace.testTable;");
      // Drop the table.
         session.execute("DROP TABLE testKeyspace.testTable ");

   • DML operations

         // Perform an insert operation.
         session.execute(
                     "INSERT INTO testKeyspace.testTable (id, name, age, address) "
                             + "VALUES ("
                             + "1,"
                             + "'testname',"
                             + "11,"
                             + "'hangzhou');");
         // Perform a select operation. `select *` retrieves all columns. To retrieve data from specific columns, specify their names.
         ResultSet res = session.execute(
                     "SELECT * FROM testKeyspace.testTable ;");
         // To retrieve data from each column:
         for (Row row : res)
         {
             int id = row.getInt("id");
             String name = row.getString("name");
             int age = row.getInt("age");
             String address = row.getString("address");
         }
         // Close the session.
         session.close();
         // Close the cluster.
         cluster.close();