Redis learning notes-2. Use of the client

1. Jedis

1.1 know Jedis

• ** Use java operation redis One of the middleware ,Redis Officially recommended java Connect development tools **

• Jedis yes Redis An official product for Java The client of , Many interfaces are provided for Java Language call .

• Use jedis object , Operation methods and functions redis Of api Exactly the same

<dependency>
	<groupId>redis.clients</groupId>
	<artifactId>jedis</artifactId>
	<version>4.1.1</version>
</dependency>

 public class TestPing {
    
     public static void main(String[] args) {
    
     	// 1、 new Jedis  Object can 
         Jedis jedis = new Jedis("127.0.0.1", 6379);
         // jedis  All the commands are all the instructions we learned before ！ So the instruction learning before is very important 
         String response = jedis.ping();
         System.out.println(response); // PONG
     }
 }

1.2 Connect Jedis

• Each time is equivalent to one TCP Connect , Threads are not safe

1.3 Easy to use

1.4 Jedis Connection pool use

Comparison with direct connection

• Don't do it every time TCP Three handshakes connected , Four waves

Easy to use

Connection pool configuration

1. Resource number control

（1） compatible maxTotal

（2） compatible maxIdle and minIdle

• Actually maxTotal The maximum number of connections represented by the , It just gives an upper limit on the number of connections ,
• and maxIdle The maximum number of idle connections represented by the , Is really the maximum number of connections available for the business .
• If maxTotal and maxIdle The two are not equal , It will involve the destruction and creation of connections , There will be some overhead , Therefore, it is recommended to set maxIdle=maxTotal, Try to avoid the performance degradation of the connection pool caused by frequent connection creation and destruction , Enable connection pooling to achieve optimal performance .
  

2. Borrow and return parameters

3. common problem

（1） Timeout connection

• maxWaitMillis Setting parameters

（2） Run out of resources

• maxIdle and minIdle Set unequal conditions

4. Solutions

5. FAQ case demonstration

• Connection leakage - Connection not closed
  
  
  
  

2. lettuce

• stay SpringBoot2.x after , Originally used jedis Was replaced by lettuce?

• jedis : Using direct connection , If multiple threads operate , It's not safe ,

  • If you want to avoid unsafe , Use jedis pool Connection pool ！ More like BIO( Blocking ) Pattern

• lettuce : use netty, Instances can be shared among multiple threads , There is no thread unsafe situation ！

  • Can reduce thread data , More like NIO Pattern

3. redis -py（Pathon client ）

3.1 obtain redis-py

3.2 Basic use

4. go Language client

4.1 Redigo Client selection

3.2 Connect

3.3 Basic use