Redis 客户端的开发

妖狐艹你老母 2022-05-19 09:42 221阅读 0赞

上篇文章 [Redis 服务器的安装部署][Redis] 讲述了 Redis 服务器的部署。本文则从 Redis 客户端角度，讲述 Java 代码访问 Redis 的三种方式（基于官方 API、基于 Spring、基于 SpringBoot)，开发者可根据自己项目所采用的框架选择。  
  
**作者：**王克锋  
**出处：**[https://kefeng.wang/2017/08/22/redis-development/][https_kefeng.wang_2017_08_22_redis-development]  
**版权：**[自由转载-非商用-非衍生-保持署名][-_-_-]，转载请标明作者和出处。

## 1 基于官方 API ##

### 1.1 pom.xml ###

<dependency>
        <groupId>redis.clients</groupId>
        <artifactId>jedis</artifactId>
        <version>2.8.1</version>
    </dependency>

### 1.2 RedisClient.java ###

public class RedisClient { 
        public static void main(String[] args) {
            try (Jedis redis = new Jedis("localhost")) {
                System.out.println("auth=" + redis.auth("passwd")); // OK
                System.out.println("ping=" + redis.ping()); // PONG
                System.out.println("keys=" + redis.keys("*")); // [user, key]
                System.out.println("type=" + redis.type("user")); // hash
                System.out.println("hash=" + redis.hgetAll("user")); // hash
            }
        }
    }

## 2 基于 Spring ##

### 2.1 pom.xml 中增加依赖项 ###

<dependency>
        <groupId>redis.clients</groupId>
        <artifactId>jedis</artifactId>
        <version>2.8.1</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-redis</artifactId>
        <version>1.7.2.RELEASE</version>
    </dependency>

### 2.2 新建配置文件 redis.properties ###

## redis
    redis.host=localhost
    redis.port=6379
    redis.pass=passwd
    
    redis.maxTotal=8
    redis.maxIdle=3
    redis.minIdle=1
    redis.maxWaitMillis=1000
    redis.testOnBorrow=true

### 2.3 新建序列化类 FastJsonRedisSerializer.java ###

public class FastJsonRedisSerializer implements RedisSerializer<Object> { 
        private static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
    
        public byte[] serialize(Object obj) throws SerializationException {
            if (obj == null) {
                return new byte[0];
            }
    
            SerializerFeature features = SerializerFeature.WriteClassName;
            return JSON.toJSONString(obj, features).getBytes(DEFAULT_CHARSET);
        }
    
        public Object deserialize(byte[] raw) throws SerializationException {
            if (raw == null || raw.length <= 0) {
                return null;
            }
    
            String str = new String(raw, DEFAULT_CHARSET);
            return JSON.parseObject(str, Object.class);
        }
    }

### 2.4 spring.xml 中配置 ###

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xmlns:redis="http://www.springframework.org/schema/redis" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/redis http://www.springframework.org/schema/redis/spring-redis-1.0.xsd">
    
        
        <context:property-placeholder location="classpath:config/redis.properties" />
    
        
        <bean id="jedisPoolConfig" class="redis.clients.jedis.JedisPoolConfig">
            <property name="maxTotal" value="${redis.maxTotal}" />
            <property name="maxIdle" value="${redis.maxIdle}" />
            <property name="maxWaitMillis" value="${redis.maxWaitMillis}" />
            <property name="testOnBorrow" value="${redis.testOnBorrow}" />
        </bean>
    
        
        <bean id="jedisFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">
            <property name="hostName" value="${redis.host}" />
            <property name="port" value="${redis.port}" />
            <property name="password" value="${redis.pass}" />
            <property name="usePool" value="true" />
            <property name="poolConfig" ref="jedisPoolConfig" />
        </bean>
    
        
        <bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
            <property name="connectionFactory" ref="jedisFactory" />
            <property name="enableTransactionSupport" value="false" />
            <property name="keySerializer">
                <bean class="org.springframework.data.redis.serializer.StringRedisSerializer" />
            </property>
            <property name="valueSerializer">
                <bean class="wang.kefeng.demo.service.FastJsonRedisSerializer" />
            </property>
        </bean>
    
    </beans>

### 2.5 方式1：单一 Jedis（非线程安全） ###

public static void demoJedisClient() {
        Jedis jedis = new Jedis("localhost", 6379);
        jedis.auth("passwd");
        jedis.set("name", "client");
        logger.info("name={}", jedis.get("name"));
        jedis.close();
    }

### 2.6 方式2：使用 JedisPool（线程安全的） ###

public static void demoJedisPool() {
        // 准备连接池参数
        JedisPoolConfig config = new JedisPoolConfig();
        config.setMinIdle(1); // 最小空闲连接数
        config.setMaxIdle(3); // 最大空闲连接数
        config.setMaxTotal(8); // 最大连接数
        config.setMaxWaitMillis(1000); // 最大阻塞时(ms)
    
        // 创建连接池[单一部署]
        Pool<Jedis> pool = null;
        pool = new JedisPool(config, "localhost", 6379);
    
        // 使用连接
        try (Jedis jedis = pool.getResource()) {
            jedis.auth("passwd");
            jedis.set("name", "pool");
            logger.info("name={}", jedis.get("name"));
    
            // auto call jedis.close();
            // Jedis对 close() 作了改造，非连接池情形下，是关闭连接；
            // 连接池情形下，是把连接对象返回到对象池，而不是关闭。
        }
    
        // 销毁连接池
        pool.close();
    }

### 2.7 方式3：Spring 方式(连接池、线程安全) ###

@SuppressWarnings("unchecked")
    public static void demoJedisSpring() {
        String file = "spring/redis.xml";
        try (ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext(file)) {
            RedisTemplate<String, Object> template = (RedisTemplate<String, Object>) ctx.getBean(RedisTemplate.class);
            ValueOperations<String, Object> jedis = template.opsForValue();
    
            Map<String, Object> maps = new HashMap<>();
            maps.put("name", "kevin");
            maps.put("age", 123);
            jedis.set("student", maps);
    
            Object obj = jedis.get("student");
            logger.info("name={}", obj.getClass().getName());
        }
    }

## 3.基于 SpringBoot ##

### 3.1 pom.xml ###

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

### 3.2 application.properties ###

### Redis
    spring.redis.host=localhost
    spring.redis.port=6379
    spring.redis.password=passwd
    spring.redis.database=0
    spring.redis.timeout=3000
    spring.redis.pool.min-idle=3
    spring.redis.pool.max-idle=8
    spring.redis.pool.max-active=16
    spring.redis.pool.max-wait=3000

### 3.3 demoJedisClient.java ###

其中的 `StringRedisTemplate` 相当于 spring-data-redis 中的 `RedisTemplate<String, String>`。

@RestController // 指定数据格式为 JSON(Apache Jackson)
    public class demoJedisClient { 
        @Autowired
        private StringRedisTemplate stringTemplate;
    
        @RequestMapping("/hello")
        public String hello() {
            String name = "test:time";
            String value = Long.toString(System.currentTimeMillis());
            stringTemplate.opsForValue().set(name, value);
            return stringTemplate.opsForValue().get(name);
        }
    }

[Redis]: https://kefeng.wang/2017/08/10/redis-installation/
[https_kefeng.wang_2017_08_22_redis-development]: https://kefeng.wang/2017/08/22/redis-development/
[-_-_-]: https://creativecommons.org/licenses/by-nc-nd/3.0/deed.zh