Basic knowledge and practical application of redis

One ： Non relational database

Two ：Redis Supported data types

1. String type string（ Commonly used ：json/xml）（ cache ）
2. Hash type hash(key–value)map
3. List the type list
4. Collection types set
5. Ordered set type sortedset（ Ranking List ）

3、 ... and ：Redis Application scenarios
1、 cache （ Data query （ High concurrency and long-term fixed data ）, End link , News content , Product content and so on ）;– Most used
2、 A list of online friends in a chat room ;
3、 Task queue ;（ seckill , Rush purchase ,12306 wait ）
4、 Application ranking （ Microwave thermal search ）;
5、 Website visit statistics ;
6、 Data expiration processing （ Send verification code ）;
7、 Distributed lock ;

Four ：window edition Redis Installation and use of
1.window edition Redis Download the official website
2.window edition Redis Directory structure of
3.window Version of Redis It's installation free , After decompressing the compressed package, you can use .
4.window edition Redis Start and close （ Server side ）
①： start-up ： double-click redis-server.exe
②： close ：Ctrl+C perhaps Close the service window
5. Connect Redis service （ client ）
①： double-click redis-cli.exe file – Command line tools
②： Graphical interface tools
6. Graphical software installation （ client ）– Later, use the graphical interface to operate
①： name
②：IP
③： Port number

5、 ... and ：Redis Data structure of
1.Redis It's a kind of advanced Key-Value Type of storage system , among key The value is a string type ,value Value support 5 Common data types .

6、 ... and ： Different data types （ Add / delete query command ）

7、 ... and ： Knowledge of general commands

8、 ... and ：Jedis Basic use of –java Language client
1.jedis It's the official first choice java Client development package （ Equate to Redis desktop manager Graphical interface client – Operation command interface ）
2.jedis The method of adding, deleting, and querying is
3.java Code demo Realization

Nine ：jedis Knowledge of connection pool
1.Jedis example ：

public class StudentService {
    


    StudentDao studentDao = new StudentDao();

    /** *  Check all student information  * @return */
    public String queryAllStudent() {
    
        // First from redis In order to get 
        Jedis jedis = JedisUtil.getJedis();
        long redisBegin = System.currentTimeMillis();
        String stusData = jedis.get("stusData");
        if(null!=stusData){
    
            long redisEnd = System.currentTimeMillis();
            System.out.println(" from redis Time consuming for query in ："+(redisEnd-redisBegin));
        }

        // To query from a database 
        if (null == stusData) {
    
            long begin = System.currentTimeMillis();
            List<Student> studentList = studentDao.queryAll();
            long end = System.currentTimeMillis();
            System.out.println(" Querying from the database takes time ："+(end-begin));
            // Turn data into json character string 
            stusData = JSON.toJSONString(studentList);
            // Save the data to redis in 
            jedis.set("stusData", stusData);
        }
      
      // Release resources 
      jedis.close();
      
        return stusData;
    }
}

Ten ：Spring Data Redis（spring Packaged Redis）– It is more convenient to use this in the future Jedis– important
1.Spring Data by Redis A tool class is provided ：RedisTemplate
2. Its usage 3 step ：
①： Introduce dependencies
②：yml perhaps properties Configure configuration parameters in （ip, port , Connection pool parameters …）
③： Inject RedisTemplate object , And the method of object calling stored value and value
3.RedisTemplate It encapsulates for Redis Various operations of five data structures

• redisTemplate.opsForValue() ： Operation string

• redisTemplate.opsForHash() ： operation hash

• redisTemplate.opsForList()： operation list

• redisTemplate.opsForSet()： operation set

• redisTemplate.opsForZSet()： operation zset

example ：

public void sendCode(String phone) {
    
    //  Verify phone number format 
    if (!RegexUtils.isPhone(phone)) {
    
        throw new LyException(ExceptionEnum.INVALID_PHONE_NUMBER);
    }

    //  Generate verification code 
    String code = RandomStringUtils.randomNumeric(6);

    //  Save the verification code to redis
    redisTemplate.opsForValue().set(KEY_PREFIX + phone, code, 1, TimeUnit.MINUTES);

    //  send out RabbitMQ The message to ly-sms
    Map<String, String> msg = new HashMap<>();
    msg.put("phone", phone);
    msg.put("code", code);
    amqpTemplate.convertAndSend(SMS_EXCHANGE_NAME, VERIFY_CODE_KEY, msg);
}