I. Preface

Practice is the sole criterion for testing truth. It's shallow on paper. If you want to know a person, just rely on personal data, even if you meet and talk about one or two sentences, it will also produce a lot of contingent results. As the saying goes, adversity can see the truth. Of course, here is not to let you go to adversity, but to have a simple interaction with redis. Although the mechanism is not detailed, there will still be a general impression of what it looks like. If you don't say much, just raise your sleeve!

2. Specific operation

1. Open eclipse and build a new Maven project.

2. Import additional jar packages:

<! - redis Toolkit - >
        <dependency>
            <groupId>redis.clients</groupId>
            <artifactId>jedis</artifactId>
            <version>3.0.1</version>
        </dependency>

3. Not much code, just two classes

(1)MyRedisTest.java

package com.spring.server.redis;

import java.util.Random;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import redis.clients.jedis.Jedis;

public class MyRedisTest {
	public static void main(String args[]){
		final String watchKeys = "watchKeys";
		ExecutorService executor = Executors.newFixedThreadPool(20);//Twenty thread pools are concurrent.
		
		final Jedis jedis = new Jedis("127.0.0.1",6379);
		System.out.println(jedis.get("myKey"));
		jedis.set(watchKeys,"100");//Set the starting number of snaps.
		jedis.close();
		
		for(int i = 0; i < 1000; i++){//Set up 1000 people to launch a snap-up
			executor.execute(new MyRunnable("user"+getRandomString(6)));
		}
		executor.shutdown();
	}

	private static String getRandomString(int length) {//Length is a random string length
		String base = "abcdefghijklmnopqrstuvwxyz0123456789";
		Random random = new Random();
		StringBuffer sb  = new StringBuffer();
		for(int i = 0; i<length; i++){
			//The purpose of this method is to generate a random int value, which is in the range of [0, n], i.e. the random int value between 0 and n, containing 0 but not n.
			int number = random.nextInt(base.length());
			//The charAt() method is used to return characters at the specified index. The index ranges from 0 to length() - 1.
			sb.append(base.charAt(number));
		}
		return sb.toString();
	}
}

 (2)MyRunnable.java

package com.spring.server.redis;

import java.util.List;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.Transaction;

public class MyRunnable implements Runnable {
	
	String watchKeys = "watchKeys";//Monitoring keys
	Jedis jedis = new Jedis("127.0.0.1",6379);
	String userInfo;
	
	public void myRunnable(){
		
	}
	public MyRunnable(String uinfo){
		this.userInfo = uinfo;
	}

	@Override
	public void run() {
		try{
			jedis.watch(watchKeys);
			
			String val = jedis.get(watchKeys);
			int valint = Integer.valueOf(val);
			
			if(valint <= 100 && valint >=1){
				Transaction  tx  = jedis.multi();//Open transaction
				tx.incrBy("watchKeys",-1);
				List<Object> list = tx.exec();//Submit the transaction and return null if watchKeys is changed at this time
				
				if(list == null || list.size()==0){
					 String failuserifo = "fail"+userInfo;
	                    String failinfo="User:" + failuserifo + "Commodity scramble fails, snap-up fails";
	                    System.out.println(failinfo);
	                    /* Business Logic of Buying Failure */
	                    jedis.setnx(failuserifo, failinfo);
				}else{
					for(Object succ : list){
						String succuserifo ="succ"+succ.toString() +userInfo ;
                        String succinfo="User:" + succuserifo + "Successful Buying, Number of Successful Buying at Present:"
                                + (1-(valint-100));
                        System.out.println(succinfo);
                        /* Business Logic of Successful Buying */
                        jedis.setnx(succuserifo, succinfo);
					}
				}
			}else{
				String failuserifo = "kcfail" + userInfo;
                String failinfo1="User:" + failuserifo + "Goods were snapped up and failed";
                System.out.println(failinfo1);
                jedis.setnx(failuserifo, failinfo1);
                // Thread.sleep(500);
                return;
			}
		}catch(Exception e){
			e.printStackTrace();
		}finally{
			jedis.close();
		}
	}
}

4. Click Run

OK! Now that the interaction with redis is over, what do you gain?