Redis学习笔记（4）—— Jedis入门

一、Jedis介绍

　　Redis不仅是使用命令来操作，现在基本上主流的语言都有客户端支持，比如Java、C、C#、C++、php、Node、js、Go等。

　　在官方网站里列的一些Java客户端，有jedis、Redisson、Jredis等，其中官方推荐使用jedis，在企业中用的最多的就是Jedis。

二、Java连接Redis

2.1 导入jar包

• commons-pool2-2.3.jar
• jedis-2.7.0.jar

2.2 单实例连接

    @Test
    public void testJedisSingle() throws Exception {
        // 1.设置ip地址和端口号
        Jedis jedis = new Jedis("192.168.25.129", 6379);
        // 2.设置数据
        jedis.set("name", "zhangsan");
        // 3.获得数据
        String name = jedis.get("name");
        System.out.println(name);
        // 4.释放资源
        jedis.close();
    }    

 　　注：如果执行上面代码时抛出如下异常

redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketTimeOutException: connect timed out

 　　必须关闭Linux防火墙

service iptables stop

2.3 连接池连接

　　@Test
    public void testJedisPool() throws Exception {
        // 1.获得连接池配置对象,设置配置项
        JedisPoolConfig config = new JedisPoolConfig();
        // 1.1 最大连接数
        config.setMaxTotal(30);
        // 1.2 最大空闲连接数
        config.setMaxIdle(10);

        // 2.获得连接池
        JedisPool jedisPool = new JedisPool(config, "192.168.25.129", 6379);

        // 3.获得核心对象
        Jedis jedis = null;
        try {
            jedis = jedisPool.getResource();
            // 4.设置数据
            jedis.set("name", "lisi");
            // 5.获得数据
            String name = jedis.get("name");
            System.out.println(name);

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (jedis != null) {
                jedis.close();
            }
            // 虚拟机关闭时,释放pool资源
            if (jedisPool != null) {
                jedisPool.close();
            }
        }
    }

2.4 集群连接

　　@Test
    public void testJedisCluster() throws Exception {
        // 第一步：使用JedisCluster对象。需要一个Set<HostAndPort>参数。Redis节点的列表。
        Set<HostAndPort> nodes = new HashSet<>();
        nodes.add(new HostAndPort("192.168.25.129", 7001));
        nodes.add(new HostAndPort("192.168.25.129", 7002));
        nodes.add(new HostAndPort("192.168.25.129", 7003));
        nodes.add(new HostAndPort("192.168.25.129", 7004));
        nodes.add(new HostAndPort("192.168.25.129", 7005));
        nodes.add(new HostAndPort("192.168.25.129", 7006));
        // 第二步：直接使用JedisCluster对象操作redis。在系统中单例存在。
        JedisCluster jedisCluster = new JedisCluster(nodes);
        jedisCluster.set("name", "zhangsan");
        String name = jedisCluster.get("name");
        // 第三步：打印结果
        System.out.println(name);
        // 第四步：系统关闭前，关闭JedisCluster对象。
        jedisCluster.close();
    }

三、接口封装

　　常用的操作redis的方法提取出一个接口，分别对应单机版和集群版创建两个实现类。redis的操作在项目中应用较广泛，可将接口和实现类放在commons的工具类中。

3.1 接口定义

public interface JedisClient {

    String set(String key, String value);
    String get(String key);
    Boolean exists(String key);
    Long expire(String key, int seconds);
    Long ttl(String key);
    Long incr(String key);
    Long hset(String key, String field, String value);
    String hget(String key, String field);
    Long hdel(String key, String... field);
}

3.2 单机版实现类

public class JedisClientPool implements JedisClient {
    
    private JedisPool jedisPool;

    public JedisPool getJedisPool() {
        return jedisPool;
    }

    public void setJedisPool(JedisPool jedisPool) {
        this.jedisPool = jedisPool;
    }

    @Override
    public String set(String key, String value) {
        Jedis jedis = jedisPool.getResource();
        String result = jedis.set(key, value);
        jedis.close();
        return result;
    }

    @Override
    public String get(String key) {
        Jedis jedis = jedisPool.getResource();
        String result = jedis.get(key);
        jedis.close();
        return result;
    }

    @Override
    public Boolean exists(String key) {
        Jedis jedis = jedisPool.getResource();
        Boolean result = jedis.exists(key);
        jedis.close();
        return result;
    }

    @Override
    public Long expire(String key, int seconds) {
        Jedis jedis = jedisPool.getResource();
        Long result = jedis.expire(key, seconds);
        jedis.close();
        return result;
    }

    @Override
    public Long ttl(String key) {
        Jedis jedis = jedisPool.getResource();
        Long result = jedis.ttl(key);
        jedis.close();
        return result;
    }

    @Override
    public Long incr(String key) {
        Jedis jedis = jedisPool.getResource();
        Long result = jedis.incr(key);
        jedis.close();
        return result;
    }

    @Override
    public Long hset(String key, String field, String value) {
        Jedis jedis = jedisPool.getResource();
        Long result = jedis.hset(key, field, value);
        jedis.close();
        return result;
    }

    @Override
    public String hget(String key, String field) {
        Jedis jedis = jedisPool.getResource();
        String result = jedis.hget(key, field);
        jedis.close();
        return result;
    }

    @Override
    public Long hdel(String key, String... field) {
        Jedis jedis = jedisPool.getResource();
        Long result = jedis.hdel(key, field);
        jedis.close();
        return result;
    }

}

 　　配置文件applicationContext-redis.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:dubbo="http://code.alibabatech.com/schema/dubbo" 
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd
    http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd
    http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.2.xsd
    http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.2.xsd">
    
    
    <!-- 配置redis单机版连接 -->
    <bean id="jedisClientPool" class="cn.e3mall.common.jedis.JedisClientPool">
        <property name="jedisPool" ref="jedisPool"/>
    </bean>
    <bean id="jedisPool" class="redis.clients.jedis.JedisPool">
        <constructor-arg name="host" value="192.168.25.129"/>
        <constructor-arg name="port" value="6379"/>
    </bean>
</beans>

3.3 集群版实现类

public class JedisClientCluster implements JedisClient {
    
    private JedisCluster jedisCluster;

    public JedisCluster getJedisCluster() {
        return jedisCluster;
    }

    public void setJedisCluster(JedisCluster jedisCluster) {
        this.jedisCluster = jedisCluster;
    }

    @Override
    public String set(String key, String value) {
        return jedisCluster.set(key, value);
    }

    @Override
    public String get(String key) {
        return jedisCluster.get(key);
    }

    @Override
    public Boolean exists(String key) {
        return jedisCluster.exists(key);
    }

    @Override
    public Long expire(String key, int seconds) {
        return jedisCluster.expire(key, seconds);
    }

    @Override
    public Long ttl(String key) {
        return jedisCluster.ttl(key);
    }

    @Override
    public Long incr(String key) {
        return jedisCluster.incr(key);
    }

    @Override
    public Long hset(String key, String field, String value) {
        return jedisCluster.hset(key, field, value);
    }

    @Override
    public String hget(String key, String field) {
        return jedisCluster.hget(key, field);
    }

    @Override
    public Long hdel(String key, String... field) {
        return jedisCluster.hdel(key, field);
    }

}

 　　spring的配置：

<!-- 配置redis集群版的连接 -->
    <bean id="jedisClientCluster" class="cn.e3mall.common.jedis.JedisClientCluster">
        <property name="jedisCluster" ref="jedisCluster"></property>
    </bean>
    <bean id="jedisCluster" class="redis.clients.jedis.JedisCluster">
        <constructor-arg>
            <set>
                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.25.129"></constructor-arg>
                    <constructor-arg name="port" value="7001"></constructor-arg>
                </bean>
                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.25.129"></constructor-arg>
                    <constructor-arg name="port" value="7002"></constructor-arg>
                </bean>
                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.25.129"></constructor-arg>
                    <constructor-arg name="port" value="7003"></constructor-arg>
                </bean>
                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.25.129"></constructor-arg>
                    <constructor-arg name="port" value="7004"></constructor-arg>
                </bean>
                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.25.129"></constructor-arg>
                    <constructor-arg name="port" value="7005"></constructor-arg>
                </bean>
                <bean class="redis.clients.jedis.HostAndPort">
                    <constructor-arg name="host" value="192.168.25.129"></constructor-arg>
                    <constructor-arg name="port" value="7006"></constructor-arg>
                </bean>
            </set>
        </constructor-arg>
    </bean>

　　注意：单机版和集群版不能共存，使用单机版时注释集群版的配置。使用集群版，把单机版注释。

3.4 封装代码测试

　　@Test
    public void testJedisClient() throws Exception {
        //初始化Spring容器
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("classpath:spring/applicationContext-redis.xml");
        //从容器中获得JedisClient对象
        JedisClient jedisClient = applicationContext.getBean(JedisClient.class);
        jedisClient.set("first", "100");
        String result = jedisClient.get("first");
        System.out.println(result);           
    }