Spring Boot（八）集成Spring Cache 和 Redis

在Spring Boot中添加spring-boot-starter-data-redis依賴：

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>

在application.properties中指定redis服務器IP、端口和密碼、鏈接數等：

# Redis服務器地址
spring.redis.host=127.0.0.1
# Redis服務器鏈接端口 使用默認端口6379能夠省略配置
#spring.redis.port=6379
# Redis服務器鏈接密碼（默認爲空）
#spring.redis.password=
# 鏈接池最大鏈接數（若是配置<=0，則沒有限制 ）
spring.redis.jedis.pool.max-active=8

使用StringRedisTemplate 和RedisTemplate

StringRedisTemplate是Spring Boot內置的操做Redis的API實現類,另外還有一個API實現類是RedisTemplate。StringRedisTemplate的API假定全部的數據類型化都是字符類型，即key和value都是字符串類型，對於常見額SpringBoot應用系統，使用字符串操做也已經足夠了，並且能方便的經過客戶端管理工具管理。StringRedisTemplate繼承RedisTemplate，與RedisTemplate不一樣的是從新設置了序列化策略，使用StringRedisSerialier類來序列化key-value，包括List、Hash、Set等數據結構。

 1 @RunWith(SpringRunner.class)
 2 @SpringBootTest
 3 public class SpringbootCacheApplicationTests {
 4 
 5     @Autowired
 6     StringRedisTemplate stringRedisTemplate; //操做 k-v 字符串
 7 
 8     @Autowired
 9 　　 RedisTemplate redisTemplate;  //k- v 都是對象
10 
11     /**
12      * redis 常見
13      * String(字符串) List(列表) Set(集合) Hash(散列) ZSet(有序集合)
14      */
15 
16     @Test
17     public void test1() {
18         stringRedisTemplate.opsForValue().append("StringKey", "字符串數值");
19         String value = stringRedisTemplate.opsForValue().get("StringKey");
20         System.out.println(value);
21     }
22 　　@Test
23 　　public void test2() {
24 
25     Product product =  productMapper.getProductById(4L);
26     redisTemplate.opsForValue().set("produxtid4",product);
27 
28 }
29 }

spring-boot-autoconfigure-2.0.4.RELEASE.jar包中RedisAutoConfiguration.java已經自動聲明瞭兩個redis操做bean：

RedisAutoConfiguration.java實現代碼：

所以咱們只要在使用的地方注入便可：

@Autowired
StringRedisTemplate stringRedisTemplate; //操做 k-v 字符串
@Autowired
RedisTemplate redisTemplate;  //k- v 都是對象

StringRedisTemplate 提供opsForValue用來操做key-value，如上面的示例，另外還提供了一系列opsForHash()、opsForList()、opsForSet()、opsForZSet()等方法用來操做不一樣結構類型的數據。

運行上面的測試方法，查看redis客戶端：

 

能夠發現，出現了一些沒法識別的字符，查看RedisTemplate源碼可這個是因爲默認使用了JDK的序列化機制，而StringRedisTemplate沒有出亂碼是由於它修改了序列化器

StringRedisTemplate實現：

 1 public class StringRedisTemplate extends RedisTemplate<String, String> {
 2 
 3    /**
 4     * Constructs a new <code>StringRedisTemplate</code> instance. {@link #setConnectionFactory(RedisConnectionFactory)}
 5     * and {@link #afterPropertiesSet()} still need to be called.
 6     */
 7    public StringRedisTemplate() {
 8       RedisSerializer<String> stringSerializer = new StringRedisSerializer();
 9       setKeySerializer(stringSerializer);
10       setValueSerializer(stringSerializer);
11       setHashKeySerializer(stringSerializer);
12       setHashValueSerializer(stringSerializer);
13    }
14 
15    /**
16     * Constructs a new <code>StringRedisTemplate</code> instance ready to be used.
17     *
18     * @param connectionFactory connection factory for creating new connections
19     */
20    public StringRedisTemplate(RedisConnectionFactory connectionFactory) {
21       this();
22       setConnectionFactory(connectionFactory);
23       afterPropertiesSet();
24    }
25 
26    protected RedisConnection preProcessConnection(RedisConnection connection, boolean existingConnection) {
27       return new DefaultStringRedisConnection(connection);
28    }
29 }

View Code

RedisTemplate實現，截取默認序列化器相關源碼：

 1 @Override
 2 public void afterPropertiesSet() {
 3 
 4    super.afterPropertiesSet();
 5 
 6    boolean defaultUsed = false;
 7 
 8    if (defaultSerializer == null) {
 9      //默認序列化器使用JdkSerializationRedisSerializer
10       defaultSerializer = new JdkSerializationRedisSerializer(
11             classLoader != null ? classLoader : this.getClass().getClassLoader());
12    }
13 
14    if (enableDefaultSerializer) {
15 
16       if (keySerializer == null) {
17          keySerializer = defaultSerializer;
18          defaultUsed = true;
19       }
20       if (valueSerializer == null) {
21          valueSerializer = defaultSerializer;
22          defaultUsed = true;
23       }
24       if (hashKeySerializer == null) {
25          hashKeySerializer = defaultSerializer;
26          defaultUsed = true;
27       }
28       if (hashValueSerializer == null) {
29          hashValueSerializer = defaultSerializer;
30          defaultUsed = true;
31       }
32    }
33 
34    if (enableDefaultSerializer && defaultUsed) {
35       Assert.notNull(defaultSerializer, "default serializer null and not all serializers initialized");
36    }
37 
38    if (scriptExecutor == null) {
39       this.scriptExecutor = new DefaultScriptExecutor<>(this);
40    }
41 
42    initialized = true;
43 }

View Code

既然RedisTemplate的默認序列化器不是很方便在redis管理工具中查看，咱們能夠本身定義一個RedisTemplate實例，修改默認的序列化器。

實現方式以下，定義一個配置類，從新注入一個RedisTemplate操做bean:

 1 @Configuration
 2 public class MyRedisConfig {
 3 
 4 　　　@Bean(name = "redisTemplate")
 5      public RedisTemplate<String,Object> redisTemplate(RedisConnectionFactory redisConnectionFactory){
 6 
 7         RedisTemplate<String,Object> redisTemplate = new RedisTemplate<>();
 8 　　　　　//參照StringRedisTemplate內部實現指定序列化器
 9         redisTemplate.setConnectionFactory(redisConnectionFactory);
10         redisTemplate.setKeySerializer(keySerializer());
11         redisTemplate.setHashKeySerializer(keySerializer());
12         redisTemplate.setValueSerializer(valueSerializer());
13         redisTemplate.setHashValueSerializer(valueSerializer());
14 
16         return redisTemplate;
17     }
18 
19     private RedisSerializer<String> keySerializer() {
20         return new StringRedisSerializer();
21     }
22 　　//使用Jackson序列化器
23     private RedisSerializer<Object> valueSerializer() {
24         return new GenericJackson2JsonRedisSerializer();
25     }
26 }

 從新運行上面的測試代碼，能夠發現redis客戶端中已經能夠正常的顯示json格式數據了。

SpringBoot集成redis + spring cache

Spring Cache集成redis的運行原理：

Spring緩存抽象模塊經過CacheManager來建立、管理實際緩存組件，當SpringBoot應用程序引入spring-boot-starter-data-redi依賴後嗎，容器中將註冊的是CacheManager實例RedisCacheManager對象，RedisCacheManager來負責建立RedisCache做爲緩存管理組件，由RedisCache操做redis服務器實現緩存數據操做。實際測試發現默認注入的RedisCacheManager操做緩存用的是RedisTemplate<Object, Object>，所以咱們須要自定義cacheManager，替換掉默認的序列化器。

實現代碼：

添加mybatis和redis依賴：

<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

添加mapper映射：

 1 @Mapper
 2 public interface ProductMapper {
 3     @Select("select * from tb_product where product_id=#{id}")
 4     Product getProductById(Long id);
 5 
 6     @Update("update tb_product set product_name=#{productName},product_desc=#{productDesc} WHERE product_id=#{productId}")
 7     int updateProduct(Product product);
 8 
 9     @Delete("delete from tb_product where product_id=#{id}")
10     void deleteProductById(Long id);
11 
12     @Select("select * from tb_product where product_name=#{productName}")
13     Product getProductByName(String productName);
14 }

Service:

 

 1 package com.sl.cache.service;
 2 import com.sl.cache.entity.Product;
 3 import com.sl.cache.mapper.ProductMapper;
 4 import org.springframework.beans.factory.annotation.Autowired;
 5 import org.springframework.cache.annotation.CacheConfig;
 6 import org.springframework.cache.annotation.CacheEvict;
 7 import org.springframework.cache.annotation.CachePut;
 8 import org.springframework.cache.annotation.Cacheable;
 9 import org.springframework.cache.annotation.Caching;
10 import org.springframework.stereotype.Service;
11 
12 @Service
13 @CacheConfig(cacheNames = "product")
14 public class ProductService {
15     @Autowired
16     private ProductMapper productMapper;
17 
18     @Cacheable(cacheNames = "product1",key = "#root.methodName+'['+#id+']'")
19     //@Cacheable(cacheNames = {"product1","product2"})// 默認key爲參數，多個參數SimpleKey [arg1,arg2]
20     //@Cacheable(cacheNames = "product",key = "#root.methodName+'['+#id+']'")
21     //@Cacheable(cacheNames = "product",keyGenerator = "myKeyGenerator")
22     //@Cacheable(cacheNames = "product",key = "#root.methodName+'['+#id+']'",condition="#a0>10",unless = "#a0==11") //或者condition="#id>10")
23     public Product getProductById(Long id){
24        Product product =productMapper.getProductById(id);
25        System.out.println(product);
26        return product;
27     }
28 
29     @CachePut(value="product",key = "#result.productId",condition = "#result!=null")
30     public  Product updateProduct(Product product){
31         int count = productMapper.updateProduct(product);
32         System.out.println("影響行數："+count);
33         if(count>0){
34             return product;
35         }else{
36             return null;
37         }
38     }
39 
40     //@CacheEvict(value="product",key="#id")
41     //@CacheEvict(value="product",allEntries = true) //清楚全部緩存
42     @CacheEvict(value="product",allEntries = true,beforeInvocation = true) //清楚全部緩存
43     public boolean deleteProductById(Long id) {
44         productMapper.deleteProductById(id);
45         return true;
46     }
47 
48     //含有CachePut註解，因此執行這個方法時必定會查詢數據庫，及時有cacheable註解
49     @Caching(
50             cacheable = {@Cacheable(value="product",key="#productName")},
51             put = {
52                     @CachePut(value="product",key="#result.productId"),
53                     @CachePut(value="product",key="#result.productName")
54             }
55     )
56     public  Product getProductByName(String productName){
57 
58         Product product =productMapper.getProductByName(productName);
59 
60          return product;
61     }
62 }

Controller:

package com.sl.cache.controller;
import com.sl.cache.entity.Product;
import com.sl.cache.service.ProductService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.stereotype.Service;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class ProductController {

    @Autowired
    private ProductService productService;

    @GetMapping("/product/{id}")
    public Product getProduct(@PathVariable("id") Long id) {

        Product product = productService.getProductById(id);
        return product;
    }

    //prooduct?productid=1&productName= &
    @GetMapping("/product")
    public Product updateProduct(Product product) {
        productService.updateProduct(product);
        return product;
    }

    @GetMapping("/delproduct")
    public String delProduct(@RequestParam(value="id") Long id) {

        productService.deleteProductById(id);
        return "ok";
    }

    @GetMapping("/product/name/{productName}")
    public Product getEmpByLastName(@PathVariable("productName") String productName){
        return productService.getProductByName(productName);
    }
}

自定義cacheManager實現：

 1 package com.sl.cache.config;
 2 import com.sl.cache.entity.Product;
 3 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 4 import org.springframework.cache.CacheManager;
 5 import org.springframework.cache.config.CacheManagementConfigUtils;
 6 import org.springframework.context.annotation.Bean;
 7 import org.springframework.context.annotation.Configuration;
 8 import org.springframework.context.annotation.Primary;
 9 import org.springframework.data.redis.cache.RedisCacheConfiguration;
10 import org.springframework.data.redis.cache.RedisCacheManager;
11 import org.springframework.data.redis.cache.RedisCacheWriter;
12 import org.springframework.data.redis.connection.RedisConnectionFactory;
13 import org.springframework.data.redis.core.RedisTemplate;
14 import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
15 import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
16 import org.springframework.data.redis.serializer.RedisSerializationContext;
17 import org.springframework.data.redis.serializer.RedisSerializer;
18 import org.springframework.data.redis.serializer.StringRedisSerializer;
19 
20 import java.net.UnknownHostException;
21 import java.time.Duration;
22 
23 @Configuration
24 public class MyRedisConfig {
25 
26     @Bean(name = "redisTemplate")
27     public RedisTemplate<String,Object> redisTemplate(RedisConnectionFactory redisConnectionFactory){
28 
29         RedisTemplate<String,Object> redisTemplate = new RedisTemplate<>();
30 
31         redisTemplate.setConnectionFactory(redisConnectionFactory);
32         redisTemplate.setKeySerializer(keySerializer());
33         redisTemplate.setHashKeySerializer(keySerializer());
34         redisTemplate.setValueSerializer(valueSerializer());
35         redisTemplate.setHashValueSerializer(valueSerializer());
36         return redisTemplate;
37     }
38 
39     @Primary
40     @Bean
41     public CacheManager cacheManager(RedisConnectionFactory redisConnectionFactory){
42         //緩存配置對象
43         RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig();
44 
45         redisCacheConfiguration = redisCacheConfiguration.entryTtl(Duration.ofMinutes(30L)) //設置緩存的默認超時時間：30分鐘
46                 .disableCachingNullValues()             //若是是空值，不緩存
47                 .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(keySerializer()))         //設置key序列化器
48                 .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer((valueSerializer())));  //設置value序列化器
49 
50         return RedisCacheManager
51                 .builder(RedisCacheWriter.nonLockingRedisCacheWriter(redisConnectionFactory))
52                 .cacheDefaults(redisCacheConfiguration).build();
53     }
54     private RedisSerializer<String> keySerializer() {
55         return new StringRedisSerializer();
56     }
57 
58     private RedisSerializer<Object> valueSerializer() {
59         return new GenericJackson2JsonRedisSerializer();
60     }
61 }

啓用緩存，添加mybatis Mapper映射掃描：

 1 @MapperScan("com.sl.cache.mapper")
 2 @SpringBootApplication
 3 @EnableCaching
 4 public class SpringbootCacheApplication {
 5 
 6     public static void main(String[] args) {
 7         SpringApplication.run(SpringbootCacheApplication.class, args);
 8 
 9     }
10 }