前言
这个系列记录我学习、使用到的Redis知识点。
什么是Redis
redis是一种支持Key-Value等多种数据结构的存储系统。可用于缓存，事件发布或订阅，高速队列等场景。该数据库使用ANSI C语言编写，支持网络，提供字符串，哈希，列表，队列，集合结构直接存取，基于内存，可持久化。
安装
Redis安装与RedisDesktopManager工具使用
SpringBoot中集成Redis
有两种方式：jedis和redistemplate，本文采用前者。
- 添加依赖
<dependency>
<groupId>redis.clients</groupId>
<artifactId>jedis</artifactId>
</dependency>
- 创建配置类读取配置
import lombok.Getter;
import lombok.Setter;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;
/**
* redis配置类
*/
@Getter
@Setter
@Component
@ConfigurationProperties(prefix = "redis")
public class RedisConfig {
private String host;
private Integer port;
private String password;
private Integer timeout;
private Integer poolMaxTotal;
private Integer poolMaxIdle;
private Integer poolMaxWait;
}
ConfigurationProperties注解默认读取的是classpath下的application.properties，redis的配置可以参考以下：
# redis
redis.host=127.0.0.1
redis.port=6379
#redis.password=
# 超时时间 s
redis.timeout= 100
# 连接池最大连接数
redis.poolMaxTotal=1000
# 连接池最大空闲连接
redis.poolMaxIdle=500
# 连接池最大等待时间 s
redis.poolMaxWait=500
- 采用工厂类统一生产redis连接，并将连接纳入spring容器管理
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Service;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;
@Service
public class RedisPoolFactory {
@Autowired
private RedisConfig redisConfig = null;
@Bean //指示返回一个Spring容器管理的Bean
public JedisPool JedisPoolFactory() {
JedisPoolConfig poolConfig = new JedisPoolConfig();
poolConfig.setMaxIdle(redisConfig.getPoolMaxIdle());
poolConfig.setMaxTotal(redisConfig.getPoolMaxTotal());
poolConfig.setMaxWaitMillis(redisConfig.getPoolMaxWait() * 1000);
JedisPool jp = new JedisPool(poolConfig, redisConfig.getHost(), redisConfig.getPort(),
redisConfig.getTimeout() * 1000, redisConfig.getPassword(), 0);
return jp;
}
}
通常的，一个JedisPool实例代表一个redis连接池。
- 使用JedisPool
接下来可以通过自动注入使用redis了。
@Autowired
private JedisPool jedisPool;
...
Jedis jedis = jedisPool.getResource(); //获取redis连接
jedis.set(key, value);
...
为了提高代码复用，将redis的存取等操作封装成服务。
import com.alibaba.fastjson.JSON;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
@Service
public class RedisService {
@Autowired
private JedisPool jedisPool;
public <T> boolean set(KeyPrefix prefix, String key, T value) {
return set(prefix, key, value, 0);
}
public <T> boolean set(KeyPrefix prefix, String key, T value, int exTime) {
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
String str = beanToString(value);
if (str == null || str.length() <= 0) {
return false;
}
//生成真正的key
String realKey = prefix.getPrefix() + key;
if (exTime == 0) {
//直接保存
jedis.set(realKey, str);
} else {
//设置过期时间
jedis.setex(realKey, exTime, str);
}
return true;
} finally {
returnToPool(jedis);
}
}
public <T> T get(KeyPrefix prefix, String key, Class<T> clazz) {
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
//生成真正的key
String realKey = prefix.getPrefix() + key;
String str = jedis.get(realKey);
T t = stringToBean(str, clazz);
return t;
} finally {
returnToPool(jedis);
}
}
/**
* 设置过期时间
*/
public Long expice(KeyPrefix prefix, String key, int exTime) {
Jedis jedis = null;
Long result = null;
try {
jedis = jedisPool.getResource();
result = jedis.expire(prefix.getPrefix() + key, exTime);
return result;
} finally {
returnToPool(jedis);
}
}
public Long del(KeyPrefix prefix, String key) {
Jedis jedis = null;
Long result = null;
try {
jedis = jedisPool.getResource();
result = jedis.del(prefix.getPrefix() + key);
return result;
} finally {
returnToPool(jedis);
}
}
/**
* 判断key是否存在
*/
public <T> boolean exists(KeyPrefix prefix, String key) {
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
//生成真正的key
String realKey = prefix.getPrefix() + key;
return jedis.exists(realKey);
} finally {
returnToPool(jedis);
}
}
/**
* 增加值
*/
public <T> Long incr(KeyPrefix prefix, String key) {
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
//生成真正的key
String realKey = prefix.getPrefix() + key;
return jedis.incr(realKey);
} finally {
returnToPool(jedis);
}
}
/**
* 减少值
*/
public <T> Long decr(KeyPrefix prefix, String key) {
Jedis jedis = null;
try {
jedis = jedisPool.getResource();
//生成真正的key
String realKey = prefix.getPrefix() + key;
return jedis.decr(realKey);
} finally {
returnToPool(jedis);
}
}
private <T> String beanToString(T value) {
if (value == null) {
return null;
}
Class<?> clazz = value.getClass();
if (clazz == int.class || clazz == Integer.class) {
return "" + value;
} else if (clazz == long.class || clazz == Long.class) {
return "" + value;
} else if (clazz == String.class) {
return (String) value;
} else {
return JSON.toJSONString(value);
}
}
private <T> T stringToBean(String str, Class<T> clazz) {
if (str == null || str.length() <= 0 || clazz == null) {
return null;
}
if (clazz == int.class || clazz == Integer.class) {
return (T) Integer.valueOf(str);
} else if (clazz == String.class) {
return (T) str;
} else if (clazz == long.class || clazz == Long.class) {
return (T) Long.valueOf(str);
} else {
return JSON.toJavaObject(JSON.parseObject(str), clazz);
}
}
private void returnToPool(Jedis jedis) {
if (jedis != null) {
jedis.close();
}
}
}
当体量够大时，键的管理不可忽视：想在redis中添加记录得提供键，键得提前注册。
KeyPrefix.java
public interface KeyPrefix {
public String getPrefix();
}
AbstractKeyPrefix.java
public abstract class AbstractKeyPrefix implements KeyPrefix {
private String prefix;
public AbstractKeyPrefix(String prefix) {
this.prefix = prefix;
}
@Override
public String getPrefix() {
String className = getClass().getSimpleName();
return className + ":" + prefix;
}
}
注册Item键
ItemKeyPrefix.java
public class ItemKeyPrefix extends AbstractKeyPrefix {
private ItemKeyPrefix(String prefix) {
super(prefix);
}
public static ItemKeyPrefix item = new ItemKeyPrefix("item");
}
使用redis：
