第19章 Redis的一些常用技术

19.1 Redis的基础事务

                      图19-1 Redis命令执行事务的过程

                     19-1:在Spring中使用Redis事务命令

 public static void testTransaction(){
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        RedisTemplate redisTemplate = applicationContext.getBean(RedisTemplate.class);
        SessionCallback callBack = (SessionCallback)(RedisOperations ops) -> {
            ops.multi();
            ops.boundValueOps("key1").set("value1");
            // 注意由于命令只是进入队列，而没有被执行，所以此处采用get命令，而value却返回为null
            String value = (String) ops.boundValueOps("key1").get();
            System.out.println("事务执行过程中，命令入队列，而没有被执行，所以value为空：value=" + value);
            // 此时list会保存之前进入队列的所有命令的结果
            ops.exec();// 执行事务
            // 事务结束后，获取value1
            value = (String) redisTemplate.opsForValue().get("key1");
            return value;
        };
        // 执行Redis的命令
        String value = (String) redisTemplate.execute(callBack);
        System.out.println(value);
    }

图19-2 使用discard命令取消事务

19.2  探索Redis事务回滚

图19-3 Redis事务遇到命令格式正确而数据类型不符合

图19-4   Redis事务遇到命令格式错误的

19.3  使用watch命令监控事务

图19-6 Redis执行事务

图19-7 测试Redis事务回滚

19.4 流水线(pipelined)

19-2：使用流水线操作Redis命令

    public static void testJedisPipeline() {
        JedisPool pool = getPool();
        Jedis jedis = pool.getResource();
        long start = System.currentTimeMillis();
        // 开启流水线
        Pipeline pipeline = jedis.pipelined();
        // 这里测试10万条的读/写2个操作
        for (int i = 0; i < 100000 ; i++) {
            int j = i + 1;
            pipeline.set("pipeline_key_" + j, "pipeline_value_" + j);
            pipeline.get("pipeline_key_" + j);
        }

        // pipeline.sync();//这里只执行同步，但是不返回结果
        // pipeline.syncAndReturnAll();将返回执行过的命令返回的List列表结果
        List result = pipeline.syncAndReturnAll();
        long end = System.currentTimeMillis();
        // 计算耗时
        System.err.println("耗时：" + (end - start) + "毫秒");
    }

19-3：使用Spring操作Redis流水线

 public static void testPipeline(){
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        RedisTemplate redisTemplate = applicationContext.getBean(RedisTemplate.class);
        // 使用Java8的Lambda表达式
        SessionCallback callBack = (SessionCallback) (RedisOperations ops) -> {
            for(int i = 0; i < 100000; i++){
                int j = i + 1;
                ops.boundValueOps("pipeline_key_" + j).set("pipeline_value_" + j);
                ops.boundValueOps("pipeline_key_" + j).get();
            }
            return null;
        };
        long start = System.currentTimeMillis();
        // 执行Redis的流水线命令
        List resultList = redisTemplate.executePipelined(callBack);
        long end = System.currentTimeMillis();
        System.err.println(end-start);
    }

19-5 发布订阅

图19-10  Redis的发布订阅过程

代码清单19-4：Redis发布订阅监听类

package com.ssm.chapter19.redis.listener;

import org.springframework.data.redis.connection.Message;
import org.springframework.data.redis.connection.MessageListener;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.SerializationException;

/*** imports ***/
public class RedisMessageListener implements MessageListener{
    private RedisTemplate redisTemplate;
    /*** 此处省略redisTemplate的setter和getter方法 ***/

    @Override
    public void onMessage(Message message, byte[] bytes) {
        // TODO Auto-generated method stub
        // 获取消息
        byte[] body = message.getBody();
        // 使用值序列化器转换
        String msgBody;
        String channelStr = null;
        try {
            msgBody = (String)
               getRedisTemplate().getValueSerializer().deserialize(body);

        System.err.println(msgBody);
        // 获取channel
        byte[] channel = message.getChannel();
        // 使用字符串序列化器转换
        channelStr = (String)
                getRedisTemplate().getStringSerializer().deserialize(channel);
        } catch (SerializationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        System.err.println(channelStr);
        // 渠道名称转换
        String bytesStr = new String(bytes);
        System.err.println(bytesStr);
    }

    public RedisTemplate getRedisTemplate() {
        return redisTemplate;
    }

    public void setRedisTemplate(RedisTemplate redisTemplate) {
        this.redisTemplate = redisTemplate;
    }
}

<?xml version='1.0' encoding='UTF-8' ?>
<!-- was: <?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:p="http://www.springframework.org/schema/p"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
       http://www.springframework.org/schema/aop
       http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context-4.0.xsd">
    <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig">
        <property name="maxIdle" value="50" />
        <property name="maxTotal" value="100" />
        <property name="maxWaitMillis" value="20000" />
    </bean>

    <bean id="stringRedisSerializer"
        class="org.springframework.data.redis.serializer.StringRedisSerializer" />

    <bean id="connectionFactory"
        class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">
        <property name="hostName" value="localhost" />
        <property name="port" value="6379" />
        <property name="poolConfig" ref="poolConfig" />
    </bean>

    <bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
        <property name="connectionFactory" ref="connectionFactory" />
        <property name="defaultSerializer" ref="stringRedisSerializer" />
        <property name="keySerializer" ref="stringRedisSerializer" />
        <property name="valueSerializer" ref="stringRedisSerializer" />
    </bean>

    <bean id="redisMsgListener"
        class="com.ssm.chapter19.redis.listener.RedisMessageListener">
        <property name="redisTemplate" ref="redisTemplate" />
    </bean>

    <bean id="topicContainer"
        class="org.springframework.data.redis.listener.RedisMessageListenerContainer"
        destroy-method="destroy">
        <!--Redis连接工厂 -->
        <property name="connectionFactory" ref="connectionFactory" />
        <!--连接池，这里只要线程池生存，才能继续监听 -->
        <property name="taskExecutor">
            <bean
                class="org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler">
                <property name="poolSize" value="2" />
            </bean>
        </property>
        <!--消息监听Map -->
        <property name="messageListeners">
            <map>
                <!--配置监听者，key-ref和bean id定义一致 -->
                <entry key-ref="redisMsgListener">
                    <!--监听类 -->
                    <bean class="org.springframework.data.redis.listener.ChannelTopic">
                        <constructor-arg value="chat" />
                    </bean>
                </entry>
            </map>
        </property>
    </bean>
</beans>

代码清单19-5：测试Redis发布订阅

package com.ssm.chapter19.main;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.data.redis.core.RedisTemplate;

public class Chapter19Main {
   public static void main(String[] args) {
        ApplicationContext applicationContext
           = new ClassPathXmlApplicationContext("applicationContext.xml");
        RedisTemplate redisTemplate = applicationContext.getBean(RedisTemplate.class);
        String channel = "chat";
        redisTemplate.convertAndSend(channel, "I am lazy!!");
   }

}

    public static void testPubSub(){
         ApplicationContext applicationContext
           = new ClassPathXmlApplicationContext("applicationContext.xml");
        RedisTemplate redisTemplate = applicationContext.getBean(RedisTemplate.class);
        String channel = "chat";
        redisTemplate.convertAndSend(channel, "I am lazy!!");
    }

   public static void main(String[] args) {
       /* ApplicationContext applicationContext
           = new ClassPathXmlApplicationContext("applicationContext.xml");
        RedisTemplate redisTemplate = applicationContext.getBean(RedisTemplate.class);
        String channel = "chat";
        redisTemplate.convertAndSend(channel, "I am lazy!!");*/
       testPubSub();
   }

19.6 超时命令

图19-11 Redis超时命令

代码清单19-6：使用Spring操作Redis超时命令

 public static void testExpire() {
       ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
       RedisTemplate redisTemplate = applicationContext.getBean(RedisTemplate.class);
       redisTemplate.execute((RedisOperations ops) -> {
           ops.boundValueOps("key1").set("value1");
           String keyValue = (String) ops.boundValueOps("key1").get();
           Long expSecond = ops.getExpire("key1");
           System.err.println(expSecond);
           boolean b = false;
           b = ops.expire("key1", 120L, TimeUnit.SECONDS);
           b = ops.persist("key1");
           Long l = 0L;
           l = ops.getExpire("key1");
           Long now = System.currentTimeMillis();
           Date date = new Date();
           date.setTime(now + 120000);
           ops.expireAt("key", date);
           return null;
       });
       }

   public static void main(String[] args) {
       /* ApplicationContext applicationContext
           = new ClassPathXmlApplicationContext("applicationContext.xml");
        RedisTemplate redisTemplate = applicationContext.getBean(RedisTemplate.class);
        String channel = "chat";
        redisTemplate.convertAndSend(channel, "I am lazy!!");*/
       //testPubSub();
       testExpire();
   }

19.7 使用Lua语言

19.7.1 执行输入Lua程序代码

图19-12   Redis执行Lua语言脚本

图19-13 使用签名运行Lua脚本

代码清单19-7：在Java中使用Lua脚本

    public static void testLuaScript(){
        // 如果是简单的对象，使用原来的封装会简易些
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        RedisTemplate redisTemplate = applicationContext.getBean(RedisTemplate.class);
        // 如果是简单的操作，使用原来的Jedis会简易些
        Jedis jedis = (Jedis) redisTemplate.getConnectionFactory().getConnection().getNativeConnection();
        // 执行简单的脚本
        String helloJava = (String) jedis.eval("return 'hello java'");
        System.out.println(helloJava);
        // 执行带参数的脚本
        jedis.eval("redis.call('set',KEYS[1],ARGV[1])",1,"lua-key","lua-value");
        String luaKey = (String) jedis.get("lua-key");
        System.out.println(luaKey);
        // 缓存脚本，返回sha1签名标识
        String sha1 = jedis.scriptLoad("redis.call('set',KEYS[1],ARGV[1])");
        // 通过标识执行脚本
        jedis.evalsha(sha1, 1, new String[]{ "sha-key", "sha-val"});
        // 获取执行脚本后的数据
        String shaVal = jedis.get("sha-key");
        System.out.println(shaVal);
        // 关闭连接
        jedis.close();
    }

代码清单19-8：可序列化的Role对象

public class Role implements Serializable{

    /**
     *
     */
    private static final long serialVersionUID = 5334128099542779325L;
    private Long id;
    private String roleName;
    private String note;
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getRoleName() {
        return roleName;
    }
    public void setRoleName(String roleName) {
        this.roleName = roleName;
    }
    public String getNote() {
        return note;
    }
    public void setNote(String note) {
        this.note = note;
    }
}

代码清单19-9：使用RedisScript接口对象通过Lua脚本操作对象

    public static void testRedisScript() {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        RedisTemplate redisTemplate = applicationContext.getBean(RedisTemplate.class);
        // 定义默认脚本封装类
        DefaultRedisScript<Role> redisScript = new DefaultRedisScript<Role>();
        // 设置脚本
        redisScript.setScriptText("redis.call('set', KEYS[1], ARGV[1]) return redis.call('get', KEYS[1])");
        // 定义操作的key列表
        List<String> keyList = new ArrayList<String>();
        keyList.add("role1");
        // 需要序列化保存和读取的对象
        Role role = new Role();
        role.setId(1L);
        role.setRoleName("role_name_1");
        role.setNote("note_1");
        // 获得标识字符串
        String sha1 = redisScript.getSha1();
        System.out.println(sha1);
        // 设置返回结果类型，如果没有这句话，结果返回为空
        redisScript.setResultType(Role.class);
        // 定义序列化器
        JdkSerializationRedisSerializer serializer = new JdkSerializationRedisSerializer();
        // 执行脚本
        // 第一个是RedisScript接口对象，第二个是参数序列化器
        // 第三个是结果序列化器，第四个是Redis的key列表，最后是参数列表
        Role obj = (Role) redisTemplate.execute(redisScript, serializer, serializer, keyList, role);
        // 打印结果
        System.out.println(obj);
    }

19.7.2  执行Lua文件

                                     代码清单19-10：test.lua

redis.call('set', KEYS[], ARGV[])
redis.call('set', KEYS[], ARGV[])
local n1 = tonumber(redis.call('get' ,KEYS[]))
local n2 = tonumber(redis.call('get' ,KEYS[]))
if n1 > n2 then
   return 

end

if n1 == n2 then

   return 

end

if n1 < n2  then

   return 

end

图19-14   redis-cli的命令执行

代码清单19-11：使用Java执行Redis脚本

 public static void testLuaFile(){
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
        RedisTemplate redisTemplate = applicationContext.getBean(RedisTemplate.class);
        // 读入文件流
        File file = new File("C:\\Users\\ZHONGZHENHUA\\Desktop\\redis-latest\\test.lua");
        byte[] bytes = getFileToByte(file);
        Jedis jedis = (Jedis) redisTemplate.getConnectionFactory().getConnection().getNativeConnection();
        // 发送文件二进制给Redis，这样Redis就会返回sha1标识
        byte[] sha1 = jedis.scriptLoad(bytes);
        // 使用返回的标识执行，其中第二个参数2，表示使用2个键
        // 而后面的字符串都转化为了二进制字节进行传输
        Object obj = jedis.evalsha(sha1, 2, "key1".getBytes(),"key2".getBytes(),"2".getBytes(),"4".getBytes());
        System.out.println(obj);
    }
    /**
     * 把文件转化为二进制数组
     *
     * @param file
     *            文件
     * @return 二进制数组
     *
     */
    public static byte[] getFileToByte(File file) {
        byte[] by = new byte[(int) file.length()];

        try {
            InputStream is = new FileInputStream(file);
            ByteArrayOutputStream bytestream = new ByteArrayOutputStream();
            byte[] bb = new byte[2048];
            int ch;
            ch = is.read(bb);
            while(ch != -1) {
                bytestream.write(bb, 0, ch);
                ch = is.read(bb);
            }
            by = bytestream.toByteArray();
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return by;

    }