HGET

Returns the value of the specified field in the hash table.

If the field does not exist, returns nil.

If the key does not exist, returns nil.

Redis Native Command Syntax

HGET key field

Parameter Description

• key: The key of the hash table
• field: The field to get the value

Detailed Explanation

The HGET command is used to get the value of the specified field stored in the hash table. It is a basic read operation used in conjunction with the HSET command.

Redisun Usage

In redisun, the HGET command is implemented through the HGetCommand class and the hget method in the Redisun class.

Basic Usage

Redisun redisun = Redisun.create(options -> {
  options.setAddress("redis://127.0.0.1:6379");
});

// Set hash table fields
redisun.hset("user:1000", "name", "Alice");
redisun.hset("user:1000", "email", "alice@example.com");

// Get hash table field value
String name = redisun.hget("user:1000", "name");
System.out.println("User name: " + name); // Output: Alice

// Get non-existent field
String age = redisun.hget("user:1000", "age");
System.out.println("User age: " + age); // Output: null

// Get field of non-existent key
String value = redisun.hget("nonexistent", "field");
System.out.println("Value: " + value); // Output: null

// Asynchronous version
CompletableFuture<String> future = redisun.asyncHget("user:1000", "email");
future.thenAccept(email -> System.out.println("User email: " + email));

Notes

1. If the given field exists in the hash table, return the value of that field
2. If the given field does not exist or the given key does not exist, return null
3. The time complexity of the HGET command is O(1)
4. Hash tables are suitable for storing objects, and HGET is the basic way to access object properties

References

• Redis HGET Command Official Documentation