如何使用 Thymleaf 在 Spring Boot 应用程序中正确缓存数据

Question

I am writing some Java code for my Spring boot application to receive a list of 40,000 elements and, through Thymeleaf post it in a dropdown field.我正在为 Spring boot 应用程序编写一些 Java 代码，以接收包含 40,000 个元素的列表，并通过 Thymeleaf 将其发布到下拉字段中。 However, I noticed that when I load the data and go to the dropdown, everything is slow.但是，我注意到当我加载数据并转到下拉列表时，一切都很慢。

I was told to cache the values and store them.我被告知要缓存这些值并存储它们。 Though I am not too familiar with this process I tried using the @Cacheable annotation for my SpringBootApplication, but it still didn't work.虽然我对这个过程不太熟悉，但我尝试对 SpringBootApplication 使用@Cacheable注释，但它仍然不起作用。 I am trying to see what I did wrong or if there is a better way to approach this issue I am having.我想看看我做错了什么，或者是否有更好的方法来解决我遇到的这个问题。

Service Layer:服务层：

@SuppressWarnings("unchecked")
@Cacheable("String")
public List<String> getServerListing(){
    StoredProcedureQuery storedProcedure = entityManager.createStoredProcedureQuery("GetAllServers");
    return storedProcedure.getResultList();

}

First, I have a stored procedure bring down all the data from the server, (~40,000 records).首先，我有一个存储过程从服务器中取出所有数据（约 40,000 条记录）。

Controller:控制器：

List<String> servers = joinQueryService.getServerListing();

modelAndView.addObject("servers", servers);

Then, I set it to a List of strings and send it to front-end.然后，我将它设置为一个字符串列表并将其发送到前端。

Thymeleaf:百里香：

<div class="row">
    <div class="col col-lg-9 search-bar">
        <div class="form-group">
            <label>Server:</label> <select class="js-example-basic-single3"
                th:field="*{servers}" id="selectData3">
                <option value=""></option>
                <option th:each="servers : ${servers}" th:value="${servers}" th:text="${servers}" />
            </select>

        </div>
    </div>
</div>

SpringBoot:弹簧靴：

@SpringBootApplication
@Cacheable
public class TaddmDevApplication {

    public static void main(String[] args) {

        Policy.setPolicy(new TaddmPolicy());

        SpringApplication.run(TaddmDevApplication.class, args);
    }

}

Answer 1

I think the problem here is: A browser will take several seconds to load and/or display such a large drop-down, regardless of how streamlined the rest of your application is.我认为这里的问题是：浏览器需要几秒钟才能加载和/或显示如此大的下拉菜单，无论您的应用程序的其余部分有多精简。

As a test, I created a text file containing nothing except a 40,000-item drop-down (test.htm):作为测试，我创建了一个文本文件，除了一个包含 40,000 项的下拉列表 (test.htm) 外，什么都不包含：

<!DOCTYPE html>
<html>
<body>
<h2>Create a drop-down List</h2>

<label for="widgets">Choose a widget:</label>

<select id="widgets">
  <option value="widget1">Widget 1</option>
  <option value="widget2">Widget 2</option>
  <option value="widget3">Widget 3</option>
  <option value="widget4">Widget 4</option>
  <option value="widget5">Widget 5</option>
  <option value="widget6">Widget 6</option>
  <option value="widget7">Widget 7</option>
  ... snipped for brevity!
  <option value="widget39998">Widget 39998</option>
  <option value="widget39999">Widget 39999</option>
  <option value="widget40000">Widget 40000</option>
</select>

</body>
</html>

I then opened that file in Chrome and recorded the processing time:然后我在 Chrome 中打开该文件并记录处理时间：

It took about 5 seconds.大约需要 5 秒钟。 There was no database fetch;没有数据库获取； no network traffic;没有网络流量； no server-side processing.没有服务器端处理。

I think the bottom line is: A drop-down of this size will be unwieldy for users, as well as being slow to handle in the browser .我认为底线是：这种大小的下拉菜单对用户来说是笨拙的，并且在浏览器中处理速度很慢。

This means your question becomes a different one: How to send a more modest amount of data to the browser, and allow the user to navigate through the results of each load, one page at a time.这意味着您的问题变得不同：如何向浏览器发送更少量的数据，并允许用户浏览每次加载的结果，一次一页。 I completely agree with your goal of "milliseconds", rather than seconds, by the way.顺便说一下，我完全同意你的“毫秒”目标，而不是秒。 That is exactly right.这是完全正确的。 Maybe you already have one, but try to have a specific goal in mind ("under 300 ms" or some such).也许你已经有了一个，但试着有一个特定的目标（“低于 300 毫秒”或类似的目标）。

Of course, there may well be optimizations in your code - but they are probably moot at this point.当然，您的代码中可能会进行优化 - 但此时它们可能没有实际意义。

Probably not the answer you wanted, but I hope this helped!可能不是您想要的答案，但我希望这会有所帮助！

如何使用 Thymleaf 在 Spring Boot 应用程序中正确缓存数据

问题描述

1 个解决方案

解决方案1
1 2020-02-15 15:51:08

如何使用 Thymleaf 在 Spring Boot 应用程序中正确缓存数据

问题描述

1 个解决方案

解决方案1 1 2020-02-15 15:51:08

解决方案1
1 2020-02-15 15:51:08