Implementing Redis aggregation queries using Java
Implementing various aggregate queries in Redis using Java can leverage Redis' Lua script functionality.
Firstly, use Maven to add Redis dependencies:
<dependency>
<groupId>redis.clients</groupId>
<artifactId>jedis</artifactId>
<version>3.6.0</version>
</dependency>
Then create a Jedis connection instance and execute the Lua script for aggregation queries:
import redis.clients.jedis.Jedis;
public class RedisAggregation {
public static void main(String[] args) {
//Create Jedis Connection
Jedis jedis = new Jedis("localhost");
//Execute sum aggregation query
String sumScript = "local sum = 0
" +
"for i, v in ipairs(ARGV) do
" +
" sum = sum + tonumber(v)
" +
"end
" +
"return sum";
String[] values = {"10", "20", "30"};
Long sum = (Long) jedis.eval(sumScript, 0, values);
System.out.println("Sum: " + sum);
//Execute count aggregation query
String countScript = "return #ARGV";
Long count = (Long) jedis.eval(countScript, 0, values);
System.out.println("Count: " + count);
//Execute average aggregation query
String averageScript = "local sum = 0
" +
"for i, v in ipairs(ARGV) do
" +
" sum = sum + tonumber(v)
" +
"end
" +
"local count = #ARGV
" +
"return sum / count";
Double average = (Double) jedis.eval(averageScript, 0, values);
System.out.println("Average: " + average);
//Close Jedis connection
jedis.close();
}
}
The above code implements three types of aggregate queries: sum, count, and average. The 'ARGV' in the script represents the incoming parameters, and aggregates multiple values by passing a parameter array in 'jedis. eval()'. Finally, execute the Lua script through 'jedis. eval()' and obtain the results.
Note: In practical applications, the script for aggregate queries may be more complex and can be customized according to specific needs.