1. Integration steps

1.1 introduction of springdataredis starter

<!-- Spring Data Redis Starter -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

1.2 write the configuration class of Spring Data Redis

Steps:

1) Create a JedisPoolConfig object. Complete some link pool configuration in this object

2) Create JedisConnectionFactory: configure redis link information

3) Create RedisTemplate: method used to perform Redis operation

The configuration classes are as follows:

package com.bjc.conf;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.StringRedisSerializer;

import redis.clients.jedis.JedisPoolConfig;

/**redis Configuration class
 * @Configuration Used to identify the class as a configuration class
 *
 */
@Configuration
public class Redisconfg {
	
	/**
	* 1.Create a JedisPoolConfig object. Complete some link pool configuration in this object
	* @Bean Annotation is used to initialize the code of loading @ Bean annotation when loading @ Configuration at boot time
	*/
	@Bean
	public JedisPoolConfig JedisPoolConfig() {
		// 1. Create connection pool object
		JedisPoolConfig pool = new JedisPoolConfig();
		// 2. Optional configuration
		pool.setMaxIdle(10);	//Maximum number of idle
		pool.setMinIdle(5);		//Minimum number of idle
		pool.setMaxTotal(20);	//Maximum number of links
		return pool;
	}
	
	/**
	* 2.Create JedisConnectionFactory: configure redis link information
	*/
	@Bean
	public JedisConnectionFactory jedisConnectionFactory(JedisPoolConfig config) {
		// 2.1 creating a JedisConnectionFactory factory factory object
		JedisConnectionFactory factory = new JedisConnectionFactory();
		
		// 2.2 setting RedisPool connection pool
		factory.setPoolConfig(config);
		
		// 2.3 setting connection information
		factory.setHostName("localhost");
		factory.setPort(6379);
		// Specify the redis database. Redis has 16 databases by default, which points to index database 0 by default
		// factory.setDatabase(1);
		
		return factory;
	}
	
	/**
	* 3.Create RedisTemplate: method used to perform Redis operation
	*/
	public RedisTemplate<String,Object> redisTemplate(JedisConnectionFactory factory) {
		// 3.1 create template object and set connection factory
		RedisTemplate<String,Object> template = new RedisTemplate<String,Object>();
		template.setConnectionFactory(factory);
		
		// 3.2 set serializer
		//Set serializer for key
		template.setKeySerializer(new StringRedisSerializer());
		//Set serializer for value
		template.setValueSerializer(new StringRedisSerializer());
		
		return template;
	}
}

1.3 simple test

package com.bjc.test;

import javax.annotation.Resource;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
public class RedisTest {

	@Resource
	private RedisTemplate<String,Object> templete;
	
	@Test
	public void test01() {
		templete.boundValueOps("name").set("Zhang San");
	}
	
	@Test
	public void test02() {
		String value = (String) templete.boundValueOps("name").get();
		System.out.println(value);
	}
	
}

View the redis tool. You can see that the stored key is name and the value is Zhang San

The result of program running is also the output of Zhang San

Note: in addition to the boundValueOps, the api for operating redis also has an opsForValue, for example:

@Test
public void test03() {
	templete.opsForValue().set("age", "21");
}

@Test
public void test04() {
	String age = (String) templete.opsForValue().get("age");
	System.out.println(age);
}

2. Extract the link parameters of Redis

2.1 extract configuration information

We put some link information of redis in the configuration class. Once the environment changes, it is inconvenient to change the code. Therefore, we can put these configuration information in the configuration file and add the following link information in the application.properties file:

spring.redis.pool.max-idle=10
spring.redis.pool.min-idle=5
spring.redis.pool.max-total=20
spring.redis.hostName=localhost
spring.redis.port=6379

Note: the prefix is customized, but the suffix is fixed. For example: spring. Redis. Pool. Max idle = 10 can be written as AAA. BBB. CCC. Max idle = 10, where Max idle is fixed.

2.2 read configuration information - @ ConfigurationProperties

We have configured the link information in the configuration file, so how can we introduce this information into our configuration class? spring provides an annotation @ ConfigurationProperties, which can extract the part with the same prefix in the configuration file, create a real body, and then show the suffix as the property of an entity. The prefix content is specified by the attribute prefix. In this way, we don't need to specify parameter information in the configuration class. We just need to create and return, and boot will automatically inject parameters into the object.

For example: modification of reading connection pool configuration information from configuration file

/**
* 1.Create a JedisPoolConfig object. Complete some link pool configuration in this object
* @Bean Annotation is used to initialize the code of loading @ Bean annotation when loading @ Configuration at boot time
*/
@Bean
@ConfigurationProperties(prefix = "spring.redis.pool")
public JedisPoolConfig JedisPoolConfig() {
	// 1. Create connection pool object
	JedisPoolConfig pool = new JedisPoolConfig();
	/** Changed to extract parameters from the configuration file, no need to specify here
	// 2. Optional configuration
	pool.setMaxIdle(10);	//Maximum number of idle
	pool.setMinIdle(5);		//Minimum number of idle
	pool.setMaxTotal(20);	//Maximum number of links
	*/
	return pool;
}

Change the Jedis connection factory configuration information to read from the configuration file

/**
* 2.Create JedisConnectionFactory: configure redis link information
*/
@Bean
@ConfigurationProperties(prefix = "spring.redis")
public JedisConnectionFactory jedisConnectionFactory(JedisPoolConfig config) {
	// 2.1 creating a JedisConnectionFactory factory factory object
	JedisConnectionFactory factory = new JedisConnectionFactory();
	
	// 2.2 setting RedisPool connection pool
	factory.setPoolConfig(config);
	
	// 2.3 setting connection information
	// factory.setHostName("localhost");
	// factory.setPort(6379);
	// Specify the redis database. Redis has 16 databases by default, which points to index database 0 by default
	// factory.setDatabase(1);
	
	return factory;
}

Test again, found that the program can run normally, indicating that the configuration has taken effect!

3. Access Java objects

The previous examples are all about string manipulation. Now let's see how to use SpringDataRedis to manipulate java objects.

3.1 save object

Create a new entity class user, directly set the user object to redis, and the program reports an error. This is because we set the serializer of value in the configuration object as string serializer. springdateRedis can't convert the object to string type, so the type conversion exception is reported. At the same time, we know that a serializable jar is provided in the spring dataredis core package, There are many serializers, as shown in the figure:

You can see the fifth serializer, JdkSerializationRedisSerializer.class. We can specify the current serializer as JdkSerializationRedisSerializer. For example:

@Test
public void test05() {
	// Reset serializer
	templete.setValueSerializer(new JdkSerializationRedisSerializer());
	templete.opsForValue().set("user", new User("Zhang San",23,new Date()));
}

Viewing redis, you can see the stored information, as shown in the figure:

 

Note: entity classes need to implement the serialization interface

3.2 taking objects

We can't call the get method directly to get the object information. We also need to re specify the serializer before getting it

For example:

@Test
public void test06() {
	// Reset serializer
	templete.setValueSerializer(new JdkSerializationRedisSerializer());
	User user = (User) templete.opsForValue().get("user");
	System.out.println(user);
}

Output results:

Note: the same effect can be achieved through boundValueOps. You also need to specify a serializer, for example;

@Test
public void test05() {
	// Reset serializer
	templete.setValueSerializer(new JdkSerializationRedisSerializer());
	templete.boundValueOps("users").set(new User("Zhang San",23,new Date()));
}
@Test
public void test06() {
	// Reset serializer
	templete.setValueSerializer(new JdkSerializationRedisSerializer());
	User user = (User) templete.boundValueOps("users").get();
	System.out.println(user);
}

4. Access entity objects in JSON format

Previously, we realized the access to the object through the serializer of jdk. However, there is an obvious defect in this way, that is, the storage space is relatively large. Compared with the JSON format, the storage way of serializing bytecode is very heavy. So, next, we will introduce how to use the JSON format to store the object.

4.1 deposits

Let's take a look at the serialization jar of the core jar of SpringDataRedis. We find that there are three serializers that can operate json: GenericJackson2JsonRedisSerializer, Jackson2JsonRedisSerializer, and JacksonJsonRedisSerializer, as shown in the figure:

We found that Jackson JSON redisserializer is an obsolete class, so we can use two other serializers

For example:

@Test
public void test07() {
	// Reset serializer
	templete.setValueSerializer(new Jackson2JsonRedisSerializer<User>(User.class));
	templete.boundValueOps("jsonUser").set(new User("Zhang San",23,new Date()));
}

Execute the program, check the redis management client, as shown in the figure, and find that the stored objects are stored in json format

 

4.2 take

The method of fetching is also very simple. You need to specify the corresponding serializer, for example;

@Test
public void test08() {
	// Reset serializer
	templete.setValueSerializer(new Jackson2JsonRedisSerializer<User>(User.class));
	User user = (User) templete.boundValueOps("jsonUser").get();
	System.out.println(user);
}