Using Java to Implement Memcached Aggregated Queries
To implement aggregation queries for Memcached using Java, you can use Java's Memcached client library. The following is a brief introduction to using the Spymemcached library to implement various aggregation queries.
Firstly, you need to add the dependency of the Spymemcached library in Maven:
<dependency>
<groupId>net.spy</groupId>
<artifactId>spymemcached</artifactId>
<version>2.12.3</version>
</dependency>
Next, you can use the following Java code to implement various data aggregation queries:
1. Aggregate Count Query:
import net.spy.memcached.MemcachedClient;
import java.net.InetSocketAddress;
public class AggregateQueryExample {
public static void main(String[] args) {
try {
//Create Memcached client connection
MemcachedClient client = new MemcachedClient(new InetSocketAddress("localhost", 11211));
//Set initial value
client.set("key1", 0, "10");
client.set("key2", 0, "15");
client.set("key3", 0, "20");
//Execute aggregation count query
int sum = Integer.parseInt((String) client.get("key1")) + Integer.parseInt((String) client.get("key2")) + Integer.parseInt((String) client.get("key3"));
System.out.println("Sum: " + sum);
//Close client connection
client.shutdown();
} catch (Exception e) {
e.printStackTrace();
}
}
}
2. Aggregate Average Query:
import net.spy.memcached.MemcachedClient;
import java.net.InetSocketAddress;
public class AggregateQueryExample {
public static void main(String[] args) {
try {
//Create Memcached client connection
MemcachedClient client = new MemcachedClient(new InetSocketAddress("localhost", 11211));
//Set initial value
client.set("key1", 0, "10");
client.set("key2", 0, "15");
client.set("key3", 0, "20");
//Execute Aggregate Average Query
int sum = Integer.parseInt((String) client.get("key1")) + Integer.parseInt((String) client.get("key2")) + Integer.parseInt((String) client.get("key3"));
int average = sum / 3;
System.out.println("Average: " + average);
//Close client connection
client.shutdown();
} catch (Exception e) {
e.printStackTrace();
}
}
}
3. Aggregate maximum value query:
import net.spy.memcached.MemcachedClient;
import java.net.InetSocketAddress;
public class AggregateQueryExample {
public static void main(String[] args) {
try {
//Create Memcached client connection
MemcachedClient client = new MemcachedClient(new InetSocketAddress("localhost", 11211));
//Set initial value
client.set("key1", 0, "10");
client.set("key2", 0, "15");
client.set("key3", 0, "20");
//Execute Aggregate Maximum Query
int max = Math.max(Math.max(Integer.parseInt((String) client.get("key1")), Integer.parseInt((String) client.get("key2"))), Integer.parseInt((String) client.get("key3")));
System.out.println("Max: " + max);
//Close client connection
client.shutdown();
} catch (Exception e) {
e.printStackTrace();
}
}
}
Please note that the above example assumes that you have already started the Memcached server locally and that it is located on the default port 11211 of 'localhost'. You can make corresponding adjustments based on your actual situation.
Implementing aggregation queries for Memcached using Java can help you quickly perform various aggregation calculations on the data stored in Memcached and obtain results.
