Simple implementation of the sorting function in Redis cache

Edis is the official preferred Java client development package for Redis. In this article we will describe how to use the Sorted set sort collection (Zsets).

Sorted set is the same as a collection, it does not have duplicate values, the biggest difference is that each element in the Sorted set is sorted.

Let's look at some of the commands first:

Import Java.util.HashMap;
Import Java.util.Map;
Import Redis.clients.jedis.Jedis;

public class Testjedis {public

static void Main (string[] args) {

    String key = ' mostusedlanguages ';

    Jedis Jedis = new Jedis ("localhost");

     Adding a value with score to the set
     Jedis.zadd (key,100, "Java");//zadd//we could add more than one value in one
     Calling
     map<double, string> scoremembers = new hashmap<double, string> ();
     Scoremembers.put (90d, "Python");
     Scoremembers.put (80d, "Javascript");
     Jedis.zadd (key, scoremembers);
     We could get
     the ' score for a System.out.println ("Number of Java Users:" + jedis.zscore (Key, "Java"));
     We could get the number of elements on the set
     System.out.println ("Number of elements:" + Jedis.zcard (key));//zcard

     }

}

In the example above we see the Zset command, in order to add elements to the Zet, we use the Zadd method, and the difference is that we pass a score value for an element, we can use the Map object to pass many objects at once, and the Zadd method can be used to add and update the scoring value of an existing element.

We can use Zscore to get the score of an element and to get the number of elements by Zcard.

For the following example, we can see other commands from Zsets:

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Import Java.util.Set;
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Import Redis.clients.jedis.Jedis;
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Import Redis.clients.jedis.Tuple;
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public class Testjedis {
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public static void Main (string[] args) {
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String key = "Mostusedlanguages";
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Jedis Jedis = new Jedis ("localhost");
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Get all the elements sorted from bottom to top
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System.out.println (Jedis.zrange (key, 0,-1));
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Get all the elements sorted from top to bottom
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System.out.println (Jedis.zrevrange (key, 0,-1));
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We could get the elements with the associated score
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Set elements = jedis.zrevrangewithscores (key, 0,-1);
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for (Tuple tuple:elements) {
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System.out.println (tuple.getelement () + "-" + Tuple.getscore ());
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}
21st

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We can increment a score for a element using Zincrby
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System.out.println ("Score before Zincrby:" + jedis.zscore (Key, "Python"));
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Incrementing the element score
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Jedis.zincrby (Key, 1, "Python");
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System.out.println ("Score after Zincrby:" + jedis.zscore (Key, "Python"));
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}
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}
By Zrange we can get the elements of a given range, it will return the sorted list of elements (from the bottom up), or you can get a list of top and bottom elements by Zrevrrange. Redis also allows us to get the element through the associated score, passing the "withscores" argument. Use the Zrevrangewithscores method of the Jedis API to return the collection of objects. Another useful command is that Zincrby can be used to increase the element's scoring value.

There are other commands for

Zsets, and here we are just introducing some basic usage related to the Jedis API. There are also a few introductions to sorting collections.