Guava: GOOGLE CORE LIBRARIES for Java Quick Getting Started Guide

Guava (GOOGLE CORE LIBRARIES for Java) Quick Getting Started Guide Overview: Guava is a set of Java -based core libraries developed by Google, providing Java developers with various powerful and practical tools and classes to simplify daily development tasks.This guide will introduce the basic concepts and common functions of Guava, and provide the corresponding Java code example. 1. Guava basic concept: -IMMUTable Collections: Provides a set of inseparable versions of collection types (such as List, SET, MAP), which is safer and thorough security to prevent data from being modified. Example code: ImmutableList<String> immutableList = ImmutableList.of("foo", "bar", "baz"); immutableList.add("qux"); // UnsupportedOperationException -Preconditions: Provides a set of tool methods for verification method parameters, which can simplify code implementation of parameter verification. Example code: public void doSomething(String value) { Preconditions.checkNotNull(value, "Value cannot be null"); // perform operation } -STRINGS (string tool): Provides common operations and conversion methods for strings, such as string stitching, separation, interception, formatting, etc. Example code: String joinedStr = Joiner.on(", ").join("foo", "bar", "baz"); System.out.println(joinedStr); // Output: foo, bar, baz List<String> splitStr = Splitter.on(",").trimResults().splitToList("foo, bar, baz"); System.out.println(splitStr); // Output: ["foo", "bar", "baz"] String substring = Strings.commonSuffix("hello world", "world"); System.out.println(substring); // Output: "world" 2. GUAVA commonly used function: -CACHES: Provides a set of tools for cache data. When you need cache data, you can use Guava Cache to automatically process the cache expiration, LRU and other strategies. Example code: LoadingCache<String, User> userCache = CacheBuilder.newBuilder() .maximumSize(100) .expireAfterWrite(10, TimeUnit.MINUTES) .build(new CacheLoader<String, User>() { public User load(String key) { return loadUserFromDatabase(key); } }); User user = userCache.get("user123"); -Eventbus (event bus): Provides a decoupled event release/subscription mechanism for decoupling between components to make the communication between components more concise and flexible. Example code: public class EventListener { @Subscribe public void onEvent(Event event) { // handle event } } EventBus eventBus = new EventBus(); eventBus.register(new EventListener()); eventBus.post(new Event()); -Optional (optional value): Provides a situation that may be elegant processing that may be empty values to avoid using NULL to improve the readability and reliability of code. Example code: Optional<String> optionalValue = Optional.ofNullable(getValue()); if (optionalValue.isPresent()) { String value = optionalValue.get(); // do something with value } else { // handle null case } The above is only a small part of the function and examples provided by Guava. You can learn more details and other functions in the Guava official documentation.By introducing Guava, you can develop Java more efficiently and improve the quality of code. I hope this guide will help you understand Guava and use it in Java development.