国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂

Home Java javaTutorial What is the reason why the return value is empty when using RedisTemplate for batch query? How to solve this problem?

What is the reason why the return value is empty when using RedisTemplate for batch query? How to solve this problem?

Apr 19, 2025 pm 05:48 PM
redis key value pair red

This article analyzes the reason why the return value is empty when using Spring Data Redis's RedisTemplate for batch query, and provides corresponding solutions. When using the executePipelined method for batch GET operation, if the result is processed directly inside the pipeline, the return value will be empty. This is because the pipeline operation will cache all commands and will not be sent to the Redis server until executePipelined is called, and internal processing cannot obtain timely returns.

Question description:

Two error examples are given in the article, both of which try to process the results of the GET command inside executePipelined , resulting in the final returned list being all null .

Problem analysis and solutions:

The core of the problem lies in the asynchronous characteristics of pipeline operations. The correct approach should be performed after executePipelined method returns the result and then uniformly handled. The first method provided in this article deserializes within a loop, which destroys the efficiency of pipeline operations. Although the second method uses SessionCallback , it still performs result processing inside the pipeline.

Improved solutions:

An improved batchGetList method is provided in the article, which correctly utilizes the return value of executePipelined :

 public<t> List<t> batchGetList(Collection<string> keys) {
    if (CollectionUtil.isEmpty(keys)) {
        return new ArrayList();
    }

    List<object> results = redisTemplate.executePipelined((RedisConnection connection) -> {
        RedisSerializer<string> keySerializer = (RedisSerializer<string> ) redisTemplate.getKeySerializer();
        for (String key : keys) {
            connection.get(keySerializer.serialize(key));
        }
        return null;
    });

    // Execute external processing results in the pipeline return results.stream()
                  .map(result -> (T) redisTemplate.getValueSerializer().deserialize((byte[]) result))
                  .collect(Collectors.toList());
}</string></string></object></string></t></t>

This method first checks whether keys are empty, and then uses executePipelined to perform batch GET operations. The key is that after the pipeline execution is finished, it uses Stream API to traverse results list and deserialize each result using redisTemplate.getValueSerializer().deserialize method, eventually returning a list with the correct data. This avoids the wrong practice of processing results inside the pipeline and ensures that the data in Redis is properly retrieved. It should be noted that this method assumes that all key-value pairs use the same deserializer. If there are multiple data types, it needs to be adjusted according to actual conditions.

What is the reason why the return value is empty when using RedisTemplate for batch query? How to solve this problem?

The above is the detailed content of What is the reason why the return value is empty when using RedisTemplate for batch query? How to solve this problem?. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undress AI Tool

Undress AI Tool

Undress images for free

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

How to develop a complete Python Web application? How to develop a complete Python Web application? May 23, 2025 pm 10:39 PM

To develop a complete Python Web application, follow these steps: 1. Choose the appropriate framework, such as Django or Flask. 2. Integrate databases and use ORMs such as SQLAlchemy. 3. Design the front-end and use Vue or React. 4. Perform the test, use pytest or unittest. 5. Deploy applications, use Docker and platforms such as Heroku or AWS. Through these steps, powerful and efficient web applications can be built.

Usage of map in java Key-value pair operation techniques for Map collections Usage of map in java Key-value pair operation techniques for Map collections May 28, 2025 pm 05:54 PM

Map collections in Java are powerful tools for handling key-value pairs of data. 1) Use HashMap to perform basic operations, such as storing and retrieving data, with an average time complexity of O(1). 2) Use getOrDefault method to count word frequency and avoid null value checking. 3) Use TreeMap to automatically sort key-value pairs. 4) Pay attention to the duplication of key-value pairs, and use putIfAbsent to avoid overwriting old values. 5) When optimizing HashMap performance, specify the initial capacity and load factor.

Java Chinese garbled problem, cause and fix for garbled code Java Chinese garbled problem, cause and fix for garbled code May 28, 2025 pm 05:36 PM

The garbled problem in Java Chinese is mainly caused by inconsistent character encoding. The repair method includes ensuring the consistency of the system encoding and correctly handling encoding conversion. 1.Use UTF-8 encoding uniformly from files to databases and programs. 2. Clearly specify the encoding when reading the file, such as using BufferedReader and InputStreamReader. 3. Set the database character set, such as MySQL using the ALTERDATABASE statement. 4. Set Content-Type to text/html;charset=UTF-8 in HTTP requests and responses. 5. Pay attention to encoding consistency, conversion and debugging skills to ensure the correct processing of data.

Analyze the performance problems that maps may cause when expanding capacity in Go language Analyze the performance problems that maps may cause when expanding capacity in Go language May 23, 2025 pm 10:00 PM

In Go, the performance problem will be triggered when the map is expanded. The following measures can be avoided: 1. Estimate the map size and set the appropriate initial capacity; 2. Process data in batches to reduce the pressure of single-scaling expansion; 3. Use sync.Map to deal with high concurrency scenarios.

blockdag (bdag): The remaining 7 days, the remaining stack before going online blockdag (bdag): The remaining 7 days, the remaining stack before going online May 26, 2025 pm 11:51 PM

For good reason, Blockdag focuses on buyer interests. Blockdag has raised an astonishing $265 million in 28 batches of its pre-sales As 2025 approaches, investors are steadily accumulating high-potential crypto projects. Whether it’s low-cost pre-sale coins that offer a lot of upside, or a blue chip network that prepares for critical upgrades, this moment provides a unique entry point. From fast scalability to flexible modular blockchain architecture, these four outstanding names have attracted attention throughout the market. Analysts and early adopters are watching closely, calling them the best crypto coins to buy short-term gains and long-term value now. 1. BlockDag (BDAG): 7 days left

How to limit user resources in Linux? How to configure ulimit? How to limit user resources in Linux? How to configure ulimit? May 29, 2025 pm 11:09 PM

Linux system restricts user resources through the ulimit command to prevent excessive use of resources. 1.ulimit is a built-in shell command that can limit the number of file descriptors (-n), memory size (-v), thread count (-u), etc., which are divided into soft limit (current effective value) and hard limit (maximum upper limit). 2. Use the ulimit command directly for temporary modification, such as ulimit-n2048, but it is only valid for the current session. 3. For permanent effect, you need to modify /etc/security/limits.conf and PAM configuration files, and add sessionrequiredpam_limits.so. 4. The systemd service needs to set Lim in the unit file

How to customize Laravel's user authentication logic? How to customize Laravel's user authentication logic? May 22, 2025 pm 09:36 PM

Custom Laravel user authentication logic can be implemented through the following steps: 1. Add additional verification conditions when logging in, such as mailbox verification. 2. Create a custom Guard class and expand the authentication process. Custom authentication logic requires a deep understanding of Laravel's authentication system and pay attention to security, performance and maintenance.

How to use ServiceWorker for offline cache How to use ServiceWorker for offline cache May 23, 2025 pm 11:06 PM

ServiceWorker implements offline caching by intercepting network requests and providing pre-cache resources. The specific steps include: 1) Register ServiceWorker and check browser support; 2) Define cache policies and pre-cache resources in the sw.js file; 3) Pre-cache resources using install event and decide to obtain resources from the cache or network in the fetch event; 4) Pay attention to version control, cache policy selection and debugging skills; 5) Optimize cache size, process dynamic content, and ensure that scripts are loaded through HTTPS.

See all articles