Memory-based distributed NoSQL database Redis (4) Jedis: How to use it

Article directory

- Knowledge point 14: Jedis: usage and Jedis dependencies
- Knowledge point 15: Jedis: building connections
- Knowledge point 16: Jedis: String operation
- Knowledge point 17: Jedis: other types of operations
- postscript

Knowledge point 14: Jedis: usage and Jedis dependencies

Goal: Master how to use Redis and build Jedis project dependencies
Path
- step1: How to use Redis
- step2: Jedis dependencies
Implementation
- How to use Redis
  - Command operation Redis, generally used in the testing and development phase
  - Distributed computing or Java programs read and write Redis, generally used for actual production development
    - Spark/Flink reads and writes Redis
    - The overall operation mode of all databases using Java is similar
```
//todo:1-Build client connection object
Connection conn = DriverManager.getConnect(url,username,password)
//todo:2-Perform the operation: all operations are in the client connection object: method
prep.execute(SQL)
//todo:3-release the connection
conn.close
```
- Jedis dependency
  - Refer to Appendix 1 to add dependencies.
Summary
- Master how to use Redis and build Jedis project dependencies

Knowledge point 15: Jedis: building connections

Goal: Implement Jedis client connection

Implementation

 //todo:1-Build connection object
    Jedisjedis = null;

    @Before
    public void getConnection(){<!-- -->
        //Method 1: Directly construct the Jedis object
// jedis = new Jedis("node1",6379);
        //Method 2: Build Jedis through connection pool
        //Build the connection pool configuration object
        JedisPoolConfig config = new JedisPoolConfig();
        config.setMaxTotal(10);//Total connection construction
        config.setMaxIdle(5);//Maximum idle connection
        config.setMinIdle(2);//Minimum idle connection
        //Build connection pool object
        JedisPool jedisPool = new JedisPool(config,"node1",6379);
        //Get connection
        jedis = jedisPool.getResource();
    }

    //todo:2-Call the method of the connection object to implement the operation


    //todo:3-release the connection
    @After
    public void closeConnection(){<!-- -->
        jedis.close();
    }

Summary
- Implement Jedis client connection

Knowledge point 16: Jedis: String operation

Goal: Implement String operations in Jedis

Implementation

set/get/incr/exists/expire/setexp/ttl

 @Test
    public void testString(){<!-- -->
        //set/get/incr/exists/expire/setexp/ttl
// jedis.set("s1","hadoop");
// System.out.println(jedis.exists("s1"));
// System.out.println(jedis.exists("s2"));
// System.out.println(jedis.get("s1"));
// jedis.set("s2","3");
// jedis.incr("s2");
// System.out.println(jedis.get("s2"));
// jedis.expire("s2",10);
// while(true){<!-- -->
// System.out.println(jedis.ttl("s2"));
// }
        //setex: When building KV, directly set the life cycle
        jedis.setex("s3",10,"oozie");

    }

Summary
- Implementing String operations in Jedis

Knowledge point 17: Jedis: other types of operations

Goal: Implement other types of operations in Jedis

Implementation

Hash type

hset/hmset/hget/hgetall/hdel/hlen/hexists

 public void testHash(){<!-- -->
        //hset/hmset/hget/hgetall/hdel/hlen/hexists
        jedis.hset("m1","name","zhangsan");
        System.out.println(jedis.hget("m1","name"));
        Map<String,String> maps = new HashMap<>();
        maps.put("age","18");
        maps.put("phone","110");
        jedis.hmset("m1",maps);
        List<String> hmget = jedis.hmget("m1", "name", "age");
        System.out.println(hmget);
        System.out.println("=");
        Map<String, String> m1 = jedis.hgetAll("m1");
        for(Map.Entry map : m1.entrySet()){<!-- -->
            System.out.println(map.getKey() + "\t" + map.getValue());
        }
        System.out.println("=");
        System.out.println(jedis.hlen("m1"));
        jedis.hdel("m1","name");
        System.out.println(jedis.hlen("m1"));
        System.out.println(jedis.hexists("m1","name"));
        System.out.println(jedis.hexists("m1","age"));
    }

List type

lpush/rpush/lrange/llen/lpop/rpop

 @Test
    public void testList(){<!-- -->
        //lpush/rpush/lrange/llen/lpop/rpop
        jedis.lpush("list1","1","2","3");
        System.out.println(jedis.lrange("list1",0,-1));
        jedis.rpush("list1","4","5","6");
        System.out.println(jedis.lrange("list1",0,-1));
        System.out.println(jedis.llen("list1"));
        jedis.lpop("list1");
        jedis.rpop("list1");
        System.out.println(jedis.lrange("list1",0,-1));
    }

Set type

sadd/smembers/sismember/scard/srem

 @Test
    public void testSet(){<!-- -->
        //sadd/smembers/sismember/scard/srem
        jedis.sadd("set1","1","2","3","1","2","3","4\ ","5","6");
        System.out.println("Length:" + jedis.scard("set1"));
        System.out.println("Content:" + jedis.smembers("set1"));
        System.out.println(jedis.sismember("set1","1"));
        System.out.println(jedis.sismember("set1","7"));
        jedis.srem("set1","2");
        System.out.println("Content:" + jedis.smembers("set1"));

    }

Zset type

zadd/zrange/zrevrange/zcard/zrem

 @Test
    public void testZset(){<!-- -->
        //zadd/zrange/zrevrange/zcard/zrem
        jedis.zadd("zset1",20.9,"yuwen");
        jedis.zadd("zset1",10.5,"yinyu");
        jedis.zadd("zset1",70.9,"shuxue");
        jedis.zadd("zset1",99.9,"shengwu");
        Set<String> zset1 = jedis.zrange("zset1", 0, -1);
        System.out.println(zset1);
        System.out.println(jedis.zrevrange("zset1",0,-1));
        System.out.println(jedis.zcard("zset1"));
        jedis.zrem("zset1","yuwen");
        System.out.println(jedis.zrangeWithScores("zset1",0,-1));
    }

Summary
- Implement other types of operations in Jedis

Postscript

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