Foreword
In the previous article, explaining the use of redis solve the problem cluster environment session shared [fast learning springboot] 11. integration redis realize session sharing , there has been introduced redis related to dependence, and by springboot configuration to achieve the session sharing. Here, we have to operate redis by RedisTemplate springboot provided.
Injection RedisTemplate
@Autowired
private StringRedisTemplate redisTemplate;
复制代码Here I injected a StringRedisTemplate, which is equivalent to RedisTemplate <String, String>, we can also customize a RedisTemplate, as follows:
@Configuration
public class RedisTemplateConfig {
@Bean
public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
RedisTemplate<String, Object> template = new RedisTemplate<>();
// 配置连接工厂
template.setConnectionFactory(factory);
return template;
}
}
复制代码I think, there is no need to customize a RedisTemplate, said that unless there are some requirements on serialization. Explain this article are based on the default StringRedisTemplate.
Set / get value
We can). Set (k, v) method to set a value opsForValue (). Get (k) by opsForValue (acquisition value method
@Test
public void testsetAndGetString() {
redisTemplate.opsForValue().set("name", "happyjava");
String name = redisTemplate.opsForValue().get("name");
System.out.println(name);
}
复制代码Results of the:
Check the value of the database redis, as follows:
Set value and simultaneously set the expiration time
opsForValue (). set provided further support simultaneous expiration time corresponding to the key
@Test
public void testSetWithExpireTime() {
redisTemplate.opsForValue().set("name2", "happyjava2", 10, TimeUnit.SECONDS);
String name2 = redisTemplate.opsForValue().get("name2");
System.out.println(name2);
}
复制代码Results of the:
happyjava2
复制代码Gets the key expiration time
We can get key method by redisTemplate.getExpire expiration time
@Test
public void testSetWithExpireTime() {
redisTemplate.opsForValue().set("name2", "happyjava2", 10, TimeUnit.SECONDS);
String name2 = redisTemplate.opsForValue().get("name2");
System.out.println(name2);
Long expire = redisTemplate.getExpire("name2", TimeUnit.SECONDS);
System.out.println(expire);
}
复制代码Execution results are as follows:
happyjava2
9
复制代码Key expiration time set
We can set an expiration time key method by redisTemplate.expire
@Test
public void testSetExpire() {
redisTemplate.expire("name",120,TimeUnit.SECONDS);
Long expire = redisTemplate.getExpire("name", TimeUnit.SECONDS);
System.out.println(expire);
}
复制代码Before setting up the name of a non-expired, here gives it an expiration time. Execution results are as follows:
119
复制代码getAndSet
We can (). GetAndSet method to get value at this time by opsForValue, and then set a new value.
@Test
public void test() {
redisTemplate.opsForValue().set("name", "123456");
String name = redisTemplate.opsForValue().getAndSet("name", "happyjava3");
System.out.println(name);
name = redisTemplate.opsForValue().get("name");
System.out.println(name);
}
复制代码Output:
123456
happyjava3
复制代码append additional
By redisTemplate.opsForValue (). Append method may additional content.
@Test
public void test() {
redisTemplate.opsForValue().append("name","append");
String name = redisTemplate.opsForValue().get("name");
System.out.println(name);
}
复制代码Here added a string "append" to the key before the name, the output results are as follows:
happyjava3append
复制代码Increment
Redis increment is in a very common method, often used this method to implement counter. We can). Increment by increment method to achieve redisTemplate.opsForValue (
@Test
public void test() {
Long count = redisTemplate.opsForValue().increment("count");
System.out.println(count);
Long count1 = redisTemplate.opsForValue().increment("count", 11);
System.out.println(count1);
}
复制代码If the key does not exist, the default increment from zero, we can also set the size of the increment value.
Decrement
We can achieve decrement by redisTemplate.opsForValue (). Decrement method
@Test
public void test() {
Long count = redisTemplate.opsForValue().decrement("count");
System.out.println(count);
Long count1 = redisTemplate.opsForValue().decrement("count", 10);
System.out.println(count1);
}
复制代码It is set if there is / are provided if there is no
setIfAbsent: If not, then Settings.
And you can set the expiration time by overloaded methods, this method is very important, you can implement a distributed lock based on this method.
setIfPresent: If there is, then Settings.
@Test
public void test() {
Boolean aBoolean = redisTemplate.opsForValue().setIfAbsent("name", "happy");
System.out.println(aBoolean);
Boolean aBoolean1 = redisTemplate.opsForValue().setIfPresent("name", "happy2");
System.out.println(aBoolean1);
}
复制代码Because the values before the name already exists, the expected output of the code is false true.
to sum up
Used herein describes the operation redis string data structures. The following disturbances in other data structures for further explanation.
Reproduced in: https: //juejin.im/post/5d05e7b0f265da1bcd37d67e