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springboot + redis

oot 判斷 warnings 讀取 remove min 定時 tro 編寫

1.添加依賴包

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

2.配置redis屬性

spring.redis.database=0
spring.redis.host=127.0.0.1
spring.redis.port=6379
spring.redis.password=
spring.redis.pool.max-active=8
spring.redis.pool.max-wait=-1
spring.redis.pool.max-idle=8
spring.redis.pool.min-idle=0
spring.redis.timeout=0

3.創建redis緩存類----》RedisCacheConfig.java

@Configuration
@EnableCaching
public class RedisCacheConfig {
@Bean
public CacheManager cacheManager(RedisTemplate<?, ?> redisTemplate){
CacheManager cacheManager = new RedisCacheManager(redisTemplate);
return cacheManager;
}
@Bean
public RedisTemplate<String, String> redisTemplate(RedisConnectionFactory factory){
RedisTemplate<String, String> redisTemplate = new RedisTemplate<String,String>();
redisTemplate.setConnectionFactory(factory);
// key序列化方式;(不然會出現亂碼;),但是如果方法上有Long等非String類型的話,會報類型轉換錯誤;
// 所以在沒有自己定義key生成策略的時候,以下這個代碼建議不要這麽寫,可以不配置或者自己實現ObjectRedisSerializer
// 或者JdkSerializationRedisSerializer序列化方式;
RedisSerializer<String> redisSerializer = new StringRedisSerializer();// Long類型不可以會出現異常信息;
redisTemplate.setKeySerializer(redisSerializer);
redisTemplate.setHashKeySerializer(redisSerializer);
return redisTemplate;
}
}

4.創建redis工具類----》RedisUtil.java

@SuppressWarnings("unchecked")
@Component
public class RedisUtil {
@SuppressWarnings("rawtypes")
@Autowired
private RedisTemplate redisTemplate;
/**
* 批量刪除對應的value
*
* @param keys
*/
public void remove(final String... keys) {
for (String key : keys) {
remove(key);
}
}
/**
* 批量刪除key
*
* @param pattern
*/
public void removePattern(final String pattern) {
Set<Serializable> keys = redisTemplate.keys(pattern);
if (keys.size() > 0)
redisTemplate.delete(keys);
}
/**
* 刪除對應的value
*
* @param key
*/
public void remove(final String key) {
if (exists(key)) {
redisTemplate.delete(key);
}
}
/**
* 判斷緩存中是否有對應的value
*
* @param key
* @return
*/
public boolean exists(final String key) {
return redisTemplate.hasKey(key);
}
/**
* 讀取緩存
*
* @param key
* @return
*/
public String get(final String key) {
Object result = null;
redisTemplate.setValueSerializer(new StringRedisSerializer());
ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue();
result = operations.get(key);
if(result==null){
return null;
}
return result.toString();
}
/**
* 寫入緩存
*
* @param key
* @param value
* @return
*/
public boolean set(final String key, Object value) {
boolean result = false;
try {
ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue();
operations.set(key, value);
result = true;
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
/**
* 寫入緩存
*
* @param key
* @param value
* @return
*/
public boolean set(final String key, Object value, Long expireTime) {
boolean result = false;
try {
ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue();
operations.set(key, value);
redisTemplate.expire(key, expireTime, TimeUnit.SECONDS);
result = true;
} catch (Exception e) {
e.printStackTrace();
}
return result;
}

public boolean hmset(String key, Map<String, String> value) {
boolean result = false;
try {
redisTemplate.opsForHash().putAll(key, value);
result = true;
} catch (Exception e) {
e.printStackTrace();
}
return result;
}

public Map<String,String> hmget(String key) {
Map<String,String> result =null;
try {
result= redisTemplate.opsForHash().entries(key);
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
}

5.編寫測試代碼(以統計用戶個數為例,將用戶個數寫入緩存,然後讀取)

1.通過定時任務獲取用戶個數,並寫入緩存

@Scheduled(cron = "*/10 * * * * ?")
public void runJobA(){
Long userCount = 0l;
List<SysUser> list = sysUserService.getUserList(null, null, null);
if(list != null){
userCount = (long) list.size();
}
System.out.println(userCount);
redisUtil.set("userCount", userCount.toString(), 100l);
}

2.從緩存獲取用戶個數

在SysUserController.java中添加以下代碼

@RequestMapping(value="/getUserCount")

@ResponseBody
public String getUserCount(){
return sysUserService.getUserCount();
}

在SysUserService.java添加以下代碼

public String getUserCount(){
return redisUtil.get("userCount");
}

6.測試

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springboot + redis