RedisTemplate访问Redis数据结构（一）——String

https://blog.youkuaiyun.com/weixin_37490221/article/details/78134521

当对String数据结构进行操作时，推荐直接使用spring-data-redis提供的StringRedisTemplate，其配置如下（详情请见如下链接：RedisTemplate访问Redis数据结构（前言））

<bean id="stringRedisTemplate" class="org.springframework.data.redis.core.StringRedisTemplate">  
    <property name="connectionFactory" ref="jedisConnFactory" />  
    <property name="keySerializer">
        <bean class="org.springframework.data.redis.serializer.StringRedisSerializer" />
    </property>
    <property name="valueSerializer">
        <bean class="org.springframework.data.redis.serializer.StringRedisSerializer" />
    </property>
    <property name="hashKeySerializer">
        <bean class="org.springframework.data.redis.serializer.StringRedisSerializer" />
    </property>
    <property name="hashValueSerializer">
        <bean class="org.springframework.data.redis.serializer.StringRedisSerializer" />
    </property> 
</bean>

RedisTemplate使用ValueOperations对String类型进行基本操作。首先初始化spring工厂获得redisTemplate和opsForValue

    private RedisTemplate<String,String> stringTemplate;
    private ValueOperations<String, String> opsForValue;

    @SuppressWarnings("unchecked")
    @Before
    public void before(){
        //初始化
        @SuppressWarnings("resource")
        ApplicationContext context = new ClassPathXmlApplicationContext("/applicationContext.xml");
        stringTemplate = (RedisTemplate<String,String>)context.getBean("stringRedisTemplate");
        opsForValue = stringTemplate.opsForValue();
    }

下面使用Junit4测试工具进行演示，各位同学可以直接粘贴源代码自行测试使用，前提是你已经安装和配置好redis哦。

V get(Object key);

    @Test
    public void  testSet(){
        //删除健（每次测试前我都会对当前测试的键进行删除，防止影响测试结果）
        stringTemplate.delete("liu1");
        opsForValue.set("liu1", "liu1");
        System.out.println(opsForValue.get("liu1"));//liu1
    }

void set(K key, V value, long timeout, TimeUnit unit);

    @Test
    public void  testSetTimeOut() throws InterruptedException{
        stringTemplate.delete("liu2");
        //加了失效机制
        opsForValue.set("liu2", "liu2", 10, TimeUnit.SECONDS);
        Thread.sleep(5000);
        System.out.println(opsForValue.get("liu2"));//liu2
        Thread.sleep(5000);
        System.out.println(opsForValue.get("liu2"));//null
    }

void set(K key, V value, long offset);

    @Test
    public void  testSetOverwrite(){
        stringTemplate.delete("liu3");
        opsForValue.set("liu3", "liu3");
        System.out.println(opsForValue.get("liu3"));//liu3
        //该方法是用 value 参数覆写(overwrite)给定 key 所储存的字符串值，从偏移量 offset 开始
        opsForValue.set("liu3", "666666", 1);
        System.out.println(opsForValue.get("liu3"));//l666666
    }

Boolean setIfAbsent(K key, V value);

    @Test
    public void  testSetIfAbsent(){
        stringTemplate.delete("liu4");
        stringTemplate.delete("liu5");
        opsForValue.set("liu4", "liu4");
        System.out.println(opsForValue.setIfAbsent("liu4", "liu4"));//false
        System.out.println(opsForValue.setIfAbsent("liu5", "liu5"));//true
    }

void multiSet(Map < ? extends K, ? extends V > map);

List multiGet(Collection < K > keys);

Boolean multiSetIfAbsent(Map< ? extends K, ? extends V > map);

    @Test
    public void  testMultiSetAndGet (){
        stringTemplate.delete("liu6");
        stringTemplate.delete("liu7");
        stringTemplate.delete("liu8");
        stringTemplate.delete("liu9");
        Map<String,String> param = new HashMap<String,String>();
        param.put("liu6", "liu6");
        param.put("liu7", "liu7");
        param.put("liu8", "liu8");
        //为多个键分别设置它们的值
        opsForValue.multiSet(param);
        List<String> keys = new ArrayList<String>();
        keys.add("liu6");
        keys.add("liu7");
        keys.add("liu8");
        //为多个键分别取出它们的值
        List<String> results = opsForValue.multiGet(keys);
        for (String result : results) {
            System.out.println(result);
            /*
                liu6
                liu7
                liu8
             */
        }
        param.clear();
        param.put("liu8", "hahaha");
        param.put("liu9", "liu9");
        //为多个键分别设置它们的值，如果存在则返回false，不存在返回true
        System.out.println(opsForValue.multiSetIfAbsent(param));//false
        System.out.println(opsForValue.get("liu8"));//liu8
    }

V getAndSet(K key, V value);

    @Test
    public void  testGetAndSet(){
        stringTemplate.delete("liu9");
        opsForValue.set("liu9", "liu9");
        //设置键的字符串值并返回其旧值
        System.out.println(opsForValue.getAndSet("liu9", "haha"));//liu9
        System.out.println(opsForValue.get("liu9"));//haha
    }

Long increment(K key, long delta);

Double increment(K key, double delta);

    @Test
    public void  testIncrement(){
        stringTemplate.delete("liu10");
        opsForValue.set("liu10", "6");
        //值增长，支持整形和浮点型
        System.out.println(opsForValue.increment("liu10", 1));//7
        System.out.println(opsForValue.increment("liu10", 1.1));//8.1
        opsForValue.set("liu10", "liu10");
        opsForValue.increment("liu10", 1);//redis.clients.jedis.exceptions.JedisDataException: ERR value is not an integer or out of range
    }

Integer append(K key, String value);

    @Test
    public void  testAppend(){
        stringTemplate.delete("liu11");
        stringTemplate.delete("liu12");
        //如果key已经存在并且是一个字符串，则该命令将该值追加到字符串的末尾。如果键不存在，则它被创建并设置为空字符串，因此APPEND在这种特殊情况下将类似于SET。
        opsForValue.append("liu11", "liu11");
        System.out.println(opsForValue.get("liu11"));//liu11
        opsForValue.set("liu12", "liu12");
        opsForValue.append("liu12", "haha");
        System.out.println(opsForValue.get("liu12"));//liu12haha
    }

String get(K key, long start, long end);

    @Test
    public void  testGetPart(){
        stringTemplate.delete("liu13");
        opsForValue.set("liu13", "liu13");
        //截取key所对应的value字符串
        System.out.println(opsForValue.get("liu13", 0, 2));//liu
    }

void set(K key, V value);

    @Test
    public void  testSize(){
        stringTemplate.delete("liu14");
        opsForValue.set("liu14", "liu14");
        //返回key所对应的value值得长度
        System.out.println(opsForValue.size("liu14"));//5
    }

Boolean setBit(K key, long offset, boolean value);

    @Test
    public void  testSetBit(){
        stringTemplate.delete("liu15");
        //true为1，false为0
        opsForValue.set("liu15", "liu15");
        //对 key 所储存的字符串值，设置或清除指定偏移量上的位(bit)
        //key键对应的值value对应的ASCII码,在offset的位置(从左向右数)变为value
        System.out.println(opsForValue.setBit("liu15", 13, true));//false
        System.out.println(opsForValue.get("liu15"));//lmu15
        for(int i = 0 ; i<"liu15".length()*8;i++){
            if(opsForValue.getBit("liu15", i)){
                System.out.print(1);
            }else{
                System.out.print(0);
            }
            //0110110001101101011101010011000100110101
        }
    }