Preface
This article will provide a redis tool class that can be used in Spring boot and Spring Cloud projects. This tool class mainly integrates common methods when using Redis as a NoSql DB. It is based on the StringRedisTemplate instance and encapsulates reading and writing. , batch writing multiple Redis hashes and other methods reduce Redis learning costs and make business code more efficient, concise and elegant.
1.pom.xml introduces the required dependencies
This dependency is mainly used to use HashMultimap. This hashmap is an enhanced version of HashMap in Java, which allows duplication of keys in key-value pairs. This feature can be used to batch update hashes in Redis. More details later.
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>31.1-jre</version>
</dependency>2. RedisUtils tool class
Go directly to the source code, create a new Class, name it RedisUtils, and then modify the first line of the package name to use it.
package com.jtyjy.smart.redis.rock.service.utils;
import com.google.common.collect.HashMultimap;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataAccessException;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.core.*;
import org.springframework.stereotype.Component;
import java.util.*;
import java.util.concurrent.TimeUnit;
/**
* @author Administrator
*/
@Component
public class RedisUtils {
@Autowired
private StringRedisTemplate redisTemplate;
public RedisUtils(StringRedisTemplate redisTemplate) {
this.redisTemplate = redisTemplate;
}
/**
* 写入缓存
*
* @param key redis键
* @param value redis值
* @return 是否成功
*/
public boolean set(final String key, String value) {
boolean result = false;
try {
ValueOperations<String, String> operations = redisTemplate.opsForValue();
operations.set(key, value);
result = true;
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
/**
* 写入缓存设置时效时间
*
* @param key redis键
* @param value redis值
* @return 是否成功
*/
public boolean set(final String key, String value, Long expireTime) {
boolean result = false;
try {
ValueOperations<String, String> operations = redisTemplate.opsForValue();
operations.set(key, value);
redisTemplate.expire(key, expireTime, TimeUnit.SECONDS);
result = true;
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
/**
* 批量删除对应的键值对
*
* @param keys Redis键名数组
*/
public void removeByKeys(final String... keys) {
for (String key : keys) {
remove(key);
}
}
/**
* 批量删除Redis key
*
* @param pattern 键名包含字符串（如：myKey*）
*/
public void removePattern(final String pattern) {
Set<String> keys = redisTemplate.keys(pattern);
if (keys != null && keys.size() > 0) {
redisTemplate.delete(keys);
}
}
/**
* 删除key,也删除对应的value
*
* @param key Redis键名
*/
public void remove(final String key) {
if (exists(key)) {
redisTemplate.delete(key);
}
}
/**
* 判断缓存中是否有对应的value
*
* @param key Redis键名
* @return 是否存在
*/
public Boolean exists(final String key) {
return redisTemplate.hasKey(key);
}
/**
* 读取缓存
*
* @param key Redis键名
* @return 是否存在
*/
public String get(final String key) {
String result = null;
ValueOperations<String, String> operations = redisTemplate.opsForValue();
result = operations.get(key);
return result;
}
/**
* 哈希 添加
*
* @param key Redis键
* @param hashKey 哈希键
* @param value 哈希值
*/
public void hmSet(String key, String hashKey, String value) {
HashOperations<String, String, String> hash = redisTemplate.opsForHash();
hash.put(key, hashKey, value);
}
/**
* 哈希获取数据
*
* @param key Redis键
* @param hashKey 哈希键
* @return 哈希值
*/
public String hmGet(String key, String hashKey) {
HashOperations<String, String, String> hash = redisTemplate.opsForHash();
return hash.get(key, hashKey);
}
/**
* 判断hash是否存在键
*
* @param key Redis键
* @param hashKey 哈希键
* @return 是否存在
*/
public boolean hmHasKey(String key, String hashKey) {
HashOperations<String, String, String> hash = redisTemplate.opsForHash();
return hash.hasKey(key, hashKey);
}
/**
* 删除hash中一条或多条数据
*
* @param key Redis键
* @param hashKeys 哈希键名数组
* @return 删除数量
*/
public long hmRemove(String key, String... hashKeys) {
HashOperations<String, String, String> hash = redisTemplate.opsForHash();
return hash.delete(key, hashKeys);
}
/**
* 获取所有哈希键值对
*
* @param key Redis键名
* @return 哈希Map
*/
public Map<String, String> hashMapGet(String key) {
HashOperations<String, String, String> hash = redisTemplate.opsForHash();
return hash.entries(key);
}
/**
* 保存Map到哈希
*
* @param key Redis键名
* @param map 哈希Map
*/
public void hashMapSet(String key, Map<String, String> map) {
HashOperations<String, String, String> hash = redisTemplate.opsForHash();
hash.putAll(key, map);
}
/**
* 列表-追加值
*
* @param key Redis键名
* @param value 列表值
*/
public void lPush(String key, String value) {
ListOperations<String, String> list = redisTemplate.opsForList();
list.rightPush(key, value);
}
/**
* 列表-获取指定范围数据
*
* @param key Redis键名
* @param start 开始行号
* @param end 结束行号
* @return 列表
*/
public List<String> lRange(String key, long start, long end) {
ListOperations<String, String> list = redisTemplate.opsForList();
return list.range(key, start, end);
}
/**
* 集合添加
*
* @param key Redis键名
* @param value 值
*/
public void add(String key, String value) {
SetOperations<String, String> set = redisTemplate.opsForSet();
set.add(key, value);
}
/**
* 集合获取
*
* @param key Redis键名
* @return 集合
*/
public Set<String> setMembers(String key) {
SetOperations<String, String> set = redisTemplate.opsForSet();
return set.members(key);
}
/**
* 有序集合添加
*
* @param key Redis键名
* @param value 值
* @param score 排序号
*/
public void zAdd(String key, String value, double score) {
ZSetOperations<String, String> zSet = redisTemplate.opsForZSet();
zSet.add(key, value, score);
}
/**
* 有序集合-获取指定范围
*
* @param key Redis键
* @param startScore 开始序号
* @param endScore 结束序号
* @return 集合
*/
public Set<String> rangeByScore(String key, double startScore, double endScore) {
ZSetOperations<String, String> zset = redisTemplate.opsForZSet();
return zset.rangeByScore(key, startScore, endScore);
}
/**
* 模糊查询Redis键名
*
* @param pattern 键名包含字符串（如：myKey*）
* @return 集合
*/
public Set<String> keys(String pattern) {
return redisTemplate.keys(pattern);
}
/**
* 获取多个hashMap
*
* @param keySet
* @return List<Map < String, String>> hashMap列表
*/
public List hashMapList(Collection<String> keySet) {
return redisTemplate.executePipelined(new SessionCallback<String>() {
@Override
public <K, V> String execute(RedisOperations<K, V> operations) throws DataAccessException {
HashOperations hashOperations = operations.opsForHash();
for (String key : keySet) {
hashOperations.entries(key);
}
return null;
}
});
}
/**
* 保存多个哈希表（HashMap）(Redis键名可重复)
*
* @param batchMap Map<Redis键名,Map<键,值>>
*/
public void batchHashMapSet(HashMultimap<String, Map<String, String>> batchMap) {
// 设置5秒超时时间
redisTemplate.expire("max", 25, TimeUnit.SECONDS);
redisTemplate.executePipelined(new RedisCallback<List<Map<String, String>>>() {
@Override
public List<Map<String, String>> doInRedis(RedisConnection connection) throws DataAccessException {
Iterator<Map.Entry<String, Map<String, String>>> iterator = batchMap.entries().iterator();
while (iterator.hasNext()) {
Map.Entry<String, Map<String, String>> hash = iterator.next();
// 哈希名,即表名
byte[] hashName = redisTemplate.getStringSerializer().serialize(hash.getKey());
Map<String, String> hashValues = hash.getValue();
Iterator<Map.Entry<String, String>> it = hashValues.entrySet().iterator();
// 将元素序列化后缓存，即表的多条哈希记录
Map<byte[], byte[]> hashes = new HashMap<byte[], byte[]>();
while (it.hasNext()) {
// hash中一条key-value记录
Map.Entry<String, String> entry = it.next();
byte[] key = redisTemplate.getStringSerializer().serialize(entry.getKey());
byte[] value = redisTemplate.getStringSerializer().serialize(entry.getValue());
hashes.put(key, value);
}
// 批量保存
connection.hMSet(hashName, hashes);
}
return null;
}
});
}
/**
* 保存多个哈希表（HashMap）(Redis键名不可以重复)
*
* @param dataMap Map<Redis键名,Map<哈希键,哈希值>>
*/
public void batchHashMapSet(Map<String, Map<String, String>> dataMap) {
// 设置5秒超时时间
redisTemplate.expire("max", 25, TimeUnit.SECONDS);
redisTemplate.executePipelined(new RedisCallback<List<Map<String, String>>>() {
@Override
public List<Map<String, String>> doInRedis(RedisConnection connection) throws DataAccessException {
Iterator<Map.Entry<String, Map<String, String>>> iterator = dataMap.entrySet().iterator();
while (iterator.hasNext()) {
Map.Entry<String, Map<String, String>> hash = iterator.next();
// 哈希名,即表名
byte[] hashName = redisTemplate.getStringSerializer().serialize(hash.getKey());
Map<String, String> hashValues = hash.getValue();
Iterator<Map.Entry<String, String>> it = hashValues.entrySet().iterator();
// 将元素序列化后缓存，即表的多条哈希记录
Map<byte[], byte[]> hashes = new HashMap<byte[], byte[]>();
while (it.hasNext()) {
// hash中一条key-value记录
Map.Entry<String, String> entry = it.next();
byte[] key = redisTemplate.getStringSerializer().serialize(entry.getKey());
byte[] value = redisTemplate.getStringSerializer().serialize(entry.getValue());
hashes.put(key, value);
}
// 批量保存
connection.hMSet(hashName, hashes);
}
return null;
}
});
}
/**
* 保存多个哈希表（HashMap）列表（哈希map的Redis键名不能重复）
*
* @param list Map<Redis键名,Map<哈希键,哈希值>>
* @see RedisUtils*.batchHashMapSet()*
*/
public void batchHashMapListSet(List<Map<String, Map<String, String>>> list) {
// 设置5秒超时时间
redisTemplate.expire("max", 25, TimeUnit.SECONDS);
redisTemplate.executePipelined(new RedisCallback<List<Map<String, String>>>() {
@Override
public List<Map<String, String>> doInRedis(RedisConnection connection) throws DataAccessException {
for (Map<String, Map<String, String>> dataMap : list) {
Iterator<Map.Entry<String, Map<String, String>>> iterator = dataMap.entrySet().iterator();
while (iterator.hasNext()) {
Map.Entry<String, Map<String, String>> hash = iterator.next();
// 哈希名,即表名
byte[] hashName = redisTemplate.getStringSerializer().serialize(hash.getKey());
Map<String, String> hashValues = hash.getValue();
Iterator<Map.Entry<String, String>> it = hashValues.entrySet().iterator();
// 将元素序列化后缓存，即表的多条哈希记录
Map<byte[], byte[]> hashes = new HashMap<byte[], byte[]>();
while (it.hasNext()) {
// hash中一条key-value记录
Map.Entry<String, String> entry = it.next();
byte[] key = redisTemplate.getStringSerializer().serialize(entry.getKey());
byte[] value = redisTemplate.getStringSerializer().serialize(entry.getValue());
hashes.put(key, value);
}
// 批量保存
connection.hMSet(hashName, hashes);
}
}
return null;
}
});
}
}
3. How to use tools
@Service
public class ProductServiceImpl implements ProductService {
@Autowired
private ProductRepository productRepository;
@Autowired
private RedisUtils redisUtils;
private final String EMPTY_CACHE = "empty";
private final Long PRODUCT_CACHE_TIMEOUT = 360L;
@Override
public Product getRedisProduct(Integer productId){
Product product;
String productCacheKey = RedisKeyPrefixConstant.PRODUCT_CACHE + productId;
String productStr = redisUtils.get(productCacheKey);
if(!StringUtils.isEmpty(productStr)){
if(EMPTY_CACHE.equals(productStr)){
return null;
}
product = JSON.parseObject(productStr,Product.class);
return product;
}
product = productRepository.findById(productId).orElse(null);
if(product!=null){
redisUtils.set(productCacheKey,JSON.toJSONString(product),getProductCacheTimeout());
return product;
}else {
redisUtils.set(productCacheKey,EMPTY_CACHE,getEmptyCacheTimeout());
return null;
}
}
}4. Detailed explanation of batch update of Redis Hash in tool class
There are two overloaded methods of batchHashMapSet() in the tool class. In particular, one of the methods supports duplication of key values, which means that two hashes with the same Redis key name can be updated or written at the same time, and then written Hash will overwrite the data written first, which is suitable for some business scenarios that synchronize data to Redis in real time.
Instructions:
HashMultimap<String, Map<String, String>> batchMap = HashMultimap.create();
redisUtils.batchHashMapSet(batchMap);