Redis of non relational database [jedis client +jedis connection cluster]

1. Jedis Introduce

Redis It's not just using commands to operate , Now basically mainstream languages have client support , such as java、C、C#、C++、php、Node.js、Go etc. .

List some on the official website Java The client of , Yes Jedis、Redisson、Jredis、JDBC-Redis、 It's officially recommended Jedis and Redisson. What is used most in enterprises is Jedis.

2. Preparation 【 Set up firewall 】

First ,redis To configure Remote connections are disabled by default , therefore , Want to use physical machine Jedis visit redis Virtual server , You need to set the firewall white list for the accessed ports . If not set, an error will be reported :

redis Remote connection failed , Connection timeout redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketTimeoutExce

secondly ,Centos7 The default is firewall As a firewall , No, iptable file . This article uses Linux The operating system is CentOS 7. So below Just explain CentOS 7 How to set firewall white list

2.1 Firewall service started , Add whitelist

First , modify redis.conf To configure

• vim redis.conf
• Here's what to change

bind 127.0.0.1   You need to comment this out , Get rid of #
protected-mode no

then , Check redis Default port (6379) Add to white list

• firewall-cmd --zone=public --add-port=6379/tcp --permanent
• Output success It's success

service iptables restart , Check again whether the port is turned on firewall-cmd --query-port=6379/tcp

• systemctl restart firewalld
• firewall-cmd --query-port=6379/tcp

2.2 Firewall service is not started ( Or shut down the firewall service in advance )

• modify /ect/firewalld/zones/public.xml file , And restart .

3. Project construction

• First eclipse Create a java engineering
• then , Add the following two jar package
  

3.1 Single instance connection redis

First , Turn on the server

import org.junit.Test;
import redis.clients.jedis.Jedis;

public class JedisClient {
    
	
	@Test
	public void jedisClient() {
    
		Jedis jedis = new Jedis("192.168.188.127",6379);
		
		// choice  0  The database  ：0-15
		jedis.select(0);
		
		// adopt jedis assignment 
		jedis.set("s2", "222");
		
		// adopt jedis Value 
		String result = jedis.get("s2");
		System.out.println(result);
		
		jedis.close();
	}
}

Output ：

222

3.2 Use jedis Connection pool connection redis

import org.junit.Test;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;

public class JedisClient {
    
	
	@Test
	public void jedisPool() {
    
		// Use jedis Connection pool connection redis The server 
		JedisPool jedispool = new JedisPool("192.168.188.127",6379);
		
		// Get through connection pool Jedis object 
		Jedis jedis = jedispool.getResource();
		
		//jedis.set("s4", "444");
		
		String result = jedis.get("s4");
		
		System.out.println(result);
		
		// close jedis client 
		jedis.close();
		
		// Close connection pool 
		jedispool.close();
			
	}

}

Output

444

4. Jedis Connect clusters

redis Detailed explanation of cluster construction

4.1 Code

package jedishm19;

import java.util.HashSet;
import java.util.Set;
import org.junit.Test;
import redis.clients.jedis.HostAndPort;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisCluster;
import redis.clients.jedis.JedisPool;


public class JedisClient {
    
	
	@Test
	public void jedisCluster() {
    
		// establish jedisCluster
		Set<HostAndPort> nodes = new HashSet<>();
		nodes.add(new HostAndPort("192.168.188.127", 7001));
		nodes.add(new HostAndPort("192.168.188.127", 7002));
		nodes.add(new HostAndPort("192.168.188.127", 7003));
		nodes.add(new HostAndPort("192.168.188.127", 7004));
		nodes.add(new HostAndPort("192.168.188.127", 7005));
		nodes.add(new HostAndPort("192.168.188.127", 7006));
		
		JedisCluster cluster = new JedisCluster(nodes);
		
		cluster.set("s6", "666");
		
		String result = cluster.get("s6");
		System.out.println(result);
		
		cluster.close();
		
	}

}

Output ：

666