Cara menggunakan Java untuk membangunkan aplikasi pangkalan data teragih berdasarkan Cassandra

<dependency>
    <groupId>com.datastax.cassandra</groupId>
    <artifactId>cassandra-driver-core</artifactId>
    <version>3.11.0</version>
</dependency>

import com.datastax.driver.core.Cluster;
import com.datastax.driver.core.Session;

public class CassandraConnection {
    private static final String CONTACT_POINTS = "127.0.0.1"; // Cassandra节点IP地址
    private static final int PORT = 9042; // Cassandra节点端口号
    
    private Cluster cluster;
    private Session session;

    public CassandraConnection() {
        cluster = Cluster.builder()
                .addContactPoints(CONTACT_POINTS)
                .withPort(PORT)
                .build();
        session = cluster.connect();
    }

    public Session getSession() {
        return this.session;
    }

    public void close() {
        session.close();
        cluster.close();
    }
}

import com.datastax.driver.core.Session;

public class CreateTable {
    private static final String KEYSPACE = "mykeyspace"; // Keyspace的名称
    private static final String TABLE = "mytable"; // 表的名称

    public void createTable() {
        Session session = new CassandraConnection().getSession();
        
        String createKeyspaceCql = String.format("CREATE KEYSPACE IF NOT EXISTS %s " +
                "WITH replication = {'class':'SimpleStrategy', 'replication_factor':3};", KEYSPACE);
        session.execute(createKeyspaceCql);
        
        String useKeyspaceCql = String.format("USE %s;", KEYSPACE);
        session.execute(useKeyspaceCql);
        
        String createTableCql = String.format("CREATE TABLE IF NOT EXISTS %s" +
                " (id UUID PRIMARY KEY, name TEXT, age INT);", TABLE);
        session.execute(createTableCql);
        
        session.close();
    }
}

import com.datastax.driver.core.Session;

public class InsertData {
    private static final String KEYSPACE = "mykeyspace"; // Keyspace的名称
    private static final String TABLE = "mytable"; // 表的名称

    public void insertData() {
        Session session = new CassandraConnection().getSession();
        
        String useKeyspaceCql = String.format("USE %s;", KEYSPACE);
        session.execute(useKeyspaceCql);
        
        String insertDataCql = String.format("INSERT INTO %s (id, name, age) " +
                "VALUES (uuid(), 'John Doe', 25);", TABLE);
        session.execute(insertDataCql);
        
        session.close();
    }
}

import com.datastax.driver.core.ResultSet;
import com.datastax.driver.core.Row;
import com.datastax.driver.core.Session;

public class QueryData {
    private static final String KEYSPACE = "mykeyspace"; // Keyspace的名称
    private static final String TABLE = "mytable"; // 表的名称

    public void queryData() {
        Session session = new CassandraConnection().getSession();
        
        String useKeyspaceCql = String.format("USE %s;", KEYSPACE);
        session.execute(useKeyspaceCql);
        
        String queryDataCql = String.format("SELECT * FROM %s;", TABLE);
        ResultSet resultSet = session.execute(queryDataCql);
        
        for (Row row : resultSet) {
            System.out.println("Name: " + row.getString("name"));
            System.out.println("Age: " + row.getInt("age"));
        }
        
        session.close();
    }
}