本篇主要講述如何使用基本的注解 @Cacheable @CachePut @CacheEvict 操作緩存
1.我們導(dǎo)入redis的依賴
<!--這里Redis我給了版本--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> <version>1.5.10.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-cache</artifactId> </dependency> <!--使用配置類時，防止亂碼需要用到的包--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-configuration-processor</artifactId> <optional>true</optional> </dependency>
2.編寫配置類
@ConfigurationProperties(prefix = "spring.cache.redis")
@Configuration
public class RedisConfig {
private Duration timeToLive = Duration.ZERO;
public void setTimeToLive(Duration timeToLive) {
this.timeToLive = timeToLive;
}
@Bean
/**
* 該bean只針對cache存入到數(shù)據(jù)亂碼問題
*/
public RedisCacheManager cacheManager(RedisConnectionFactory factory) {
RedisSerializer<String> redisSerializer = new StringRedisSerializer();
Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
//解決查詢緩存轉(zhuǎn)換異常的問題
ObjectMApper om = new ObjectMapper();
om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
jackson2JsonRedisSerializer.setObjectMapper(om);
// 配置序列化（解決亂碼的問題）
RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
.entryTtl(timeToLive)
.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer))
.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer))
.disableCachingNullValues();
RedisCacheManager cacheManager = RedisCacheManager.builder(factory)
.cacheDefaults(config)
.build();
return cacheManager;
}
}
3.配置文件
#要連接的數(shù)據(jù)是哪個 spring.redis.database=1 #數(shù)據(jù)連接地址 spring.redis.host=localhost #端口號 spring.redis.port=6379 #連接超時時間 spring.redis.timeout=1s #最大連接數(shù) spring.redis.jedis.pool.max-active=20 #最大空閑連接 spring.redis.jedis.pool.max-idle=20 #最小空閑連接 spring.redis.jedis.pool.min-idle=10 #最大等待阻塞等待時間 spring.redis.jedis.pool.max-wait=-1ms #在寫入Redis時是否要使用key前綴 spring.cache.redis.use-key-prefix=true #key前綴 spring.cache.redis.key-prefix=dev #是否允許有null值 spring.cache.redis.cache-null-values=false #設(shè)置緩存存在時間，只針對cacheable存入數(shù)據(jù)有用 spring.cache.redis.time-to-live=120s
4.現(xiàn)在我們的環(huán)境準(zhǔn)備好了，開始編寫代碼
這里是pojo
@Table(name = "user1")
public class User implements Serializable {
@Id
private Integer id;
private String name;
private String pwd;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPwd() {
return pwd;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", name='" + name + ''' +
", pwd='" + pwd + ''' +
'}';
}
}
這里是dao類
@org.Apache.ibatis.annotations.Mapper
public interface UserMapper extends Mapper<User> {
}
這里是在service類上使用注解
@CacheConfig(cacheNames = "user")//注意,用于同一配置給其它注解配置名稱
public class UserServiceImpl implements UserService {
@Autowired
private UserMapper userMapper;
@Override
@Cacheable(key="#p0")//該注解用于向緩存中存入數(shù)據(jù)
public User findUser(Integer id) {
System.out.println("查詢數(shù)據(jù)了"+id);
User user = userMapper.selectByPrimaryKey(id);
return user;
}
@Override
@CachePut(key="#p0.id")//該注解用于更新緩存中的注解
public User updateUser(User user) {
userMapper.updateByPrimaryKeySelective(user);
return user;
}
@Override
@CacheEvict(key="#p0")//該注解用于刪除緩存
public void deleteUser(Integer id) {
userMapper.deleteByPrimaryKey(id);
}
@Override
public List<User> findUsers() {
return userMapper.selectAll();
}
}
注意，這里需要說明一下，#p0代表第一個參數(shù)，返回值默認(rèn)是方法的返回值,@Cacheable之類的注解必須要有value值，這里我在類上加@CacheConfig注解，使下面的注解有了同一個value值
這里是controller里面的代碼
@RestController
@RequestMapping("/user")
public class UserController {
@Resource
private UserService userService;
@GetMapping
public ResponseEntity<List<User>> findUsers(){
try {
List<User> users = userService.findUsers();
return new ResponseEntity<>(users,HttpStatus.OK);
} catch (Exception e) {
e.printStackTrace();
return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);
}
}
@GetMapping("/{id}")
public ResponseEntity<User> findUser(@PathVariable("id")Integer id){
try {
User user = userService.findUser(id);
return new ResponseEntity<>(user, HttpStatus.OK);
} catch (Exception e) {
e.printStackTrace();
return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);
}
}
@PutMapping
public ResponseEntity<String> updateUser(@RequestBody User user){
try {
userService.updateUser(user);
return new ResponseEntity<>("修改成功",HttpStatus.OK);
} catch (Exception e) {
e.printStackTrace();
return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);
}
}
@DeleteMapping("/{id}")
public ResponseEntity<Void> deleteUser(@PathVariable("id")Integer id){
try {
userService.deleteUser(id);
return new ResponseEntity<>(HttpStatus.OK);
} catch (Exception e) {
e.printStackTrace();
return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);
}
}
}
5.這里是數(shù)據(jù)庫的數(shù)據(jù)
6.好了，后臺代碼到這基本就完成了，現(xiàn)在自己編寫一下前臺，完成測試
- 最后說一下需要注意的點(diǎn)，配置文件中的時間配置規(guī)定了緩存存在的時間，這里我設(shè)置的是120s
- 這里的配置類必須這樣配置，否則，存入到數(shù)據(jù)的數(shù)據(jù)會亂碼
- 更新的時候，注意方法的返回值，否則數(shù)據(jù)存入的數(shù)據(jù)為null
來源：csdn 原文鏈接：https://blog.csdn.net/qq_43646524/article/details/102693454
