How to use Kotlin Test JS framework to simulate dependencies and interaction Kotlin Test JS is a framework for testing in the JavaScript environment.It uses Kotlin's syntax and characteristics, and provides some powerful tools to help us simulate external dependencies and test interaction in the code. In this article, we will introduce how to use the Kotlin Test JS framework to simulate the interaction between external dependencies and code.The following is an example that demonstrates how to test a simple function, which depends on another external function to calculate. [Paragraph 1] First, we need to install the Kotlin Test JS framework.You can complete this step by adding the following dependencies to the project's Build. Gradle file: ```kotlin dependencies { testImplementation 'io.kotest:kotest-runner-junit5:4.0.6' } ``` [Paragraph 2] Next, we can create a test class and use the annotations provided by Kotlin Test JS to mark the test method.The following is a simple example: ```kotlin import io.kotest.core.spec.style.StringSpec import io.kotest.matchers.shouldBe class MyTest : StringSpec() { @Test fun `test my function`() { val result = myFunction(5) result shouldBe 10 } } ``` [Paragraph 3] In the above example, we define a test class called MyTest and use @test annotations to mark functions to be tested.In the test method, we call a function called MyFunction and compare whether its return value is equal to the expected result. [Paragraph 4] In this example, the MyFunction function may depend on external functions for calculation.To simulate this dependencies, we can use the MockKk library of Kotlin Test JS.Mockk is a popular Kotlin Mocking framework that helps us build simulation objects and specify its behavior. [Paragraph 5] The following is an example. It demonstrates how to use the Mockk framework to simulate external functions: ```kotlin import io.kotest.core.spec.style.StringSpec import io.kotest.matchers.shouldBe import io.mockk.every import io.mockk.mockk class MyTest : StringSpec() { @Test fun `test my function`() { val externalFunction = mockk<ExternalFunction>() every { externalFunction.calculate(any()) } returns 7 val result = myFunction(5, externalFunction) result shouldBe 35 } } ``` [Paragraph 6] In the above example, we use the Mockk framework to create an analog object named ExternalFunction.Then, we use everything {excernalFunction.calCulating (Any ())} Return 7 expression to specify the value that should be returned when calling the externalFunction.calCulating (). [Paragraph 7] Finally, in the test method, we pass the simulation object to the MyFunction function and check whether its return value matches the expected result. [Paragraph 8] By using the Kotlin Test JS framework and the Mockk frame, we can easily simulate the interaction between external dependencies and test code.This has provided us with a lot of help for us to write high -efficiency and reliable tests. I hope this article can help you understand how to use the Kotlin Test JS framework to simulate dependence and interaction.If you have any questions, ask questions at any time.

How to optimize the development efficiency of the Java class library in the Libraft Core framework introduction: In the process of the development of the Java library, a problem we often face is how to improve development efficiency, reduce code complexity, and maintain the maintenance of code.The Libraft Core framework is a framework designed for the development of Java class libraries. By providing a set of powerful functions and tools, it helps developers to build and maintain the class library more efficiently to improve development efficiency. 1. What is Libraft Core framework Libraft Core is an open source Java class library development framework, which aims to provide a set of convenient tools and functions to help Java developers better design, implement and test the class library.This framework is based on some popular design models and best practices, which promotes developers to follow standard and standardized development models, thereby improving the readability, maintenance, and testability of code. Second, the advantage of libraft core 1. Highly customized: libraft core allows developers to customize the framework by configure files and annotations to meet the needs of different projects.Developers can selectively enable or disable certain functions according to their needs. 2. Simplify common tasks: Libraft Core provides rich tools and functions to help developers simplify common tasks, such as abnormal processing, log records and configuration management.Developers can focus on the development of core business logic without paying too much attention to these trivial details. 3. Provide consistent development styles: libraft core follows some popular design models and coding specifications, and encourage developers to write code with high internal agglomeration and low coupling.This makes the code of the class library easier to understand, maintain and expand. 4. Strong scalability: The Librat Core framework provides a series of interfaces and abstract classes, so that developers can easily expand based on the framework.By inheriting and implementing these interfaces, developers can quickly add new functions to class libraries or adapt to different environments. Third, the use of libraft core 1. Abnormal treatment: ```java @ExceptionHandler(IOException.class) public void handleIOException(IOException e) { // Process ioException abnormalities // ... } ``` 2. Logging: ```java @Logger public class MyClass { // ... } ``` 3. Configuration management: ```java @Configuration public class MyConfiguration { @Value("app.name") private String appName; // ... } ``` Fourth, summary The Libraft Core framework is an excellent tool for developing and designing the Java class library. It provides a series of powerful functions and tools to help developers liberate from heavy trivial matters and focus on the core business logic of the class library.By using the LIBRAFT CORE framework reasonably, we can reduce the complexity of development and improve the readability and maintenance of code.It is hoped that developers can make full use of this framework to improve the efficiency of the development of the Java library.

Application case of the 'Contracts for Java' framework in the Java class library 'Contracts for Java' is a framework in the Java class library to help developers write more robust, maintenance and easy -to -understand code.It provides a way to define and enforce the front conditions, rear conditions, and classes of the code, and verify these conditions by asserting and exceptions. By using 'Contracts for Java', developers can express their intentions in a statement in a statement and ensure that the code follows these constraints during runtime.This helps improve the readability, maintenance and reliability of the code. The following is a simple application case, showing how to use the 'Contracts for Java' framework. Case: Bank account Suppose we want to implement a bank account class, which has the function of deposit and withdrawal.In this case, we will use "Contracts for Java" to define some constraints and ensure that the code meets these constraints. First, we need to add the dependencies of the 'Contracts for Java' framework to the project. Maven dependence: ```xml <dependency> <groupId>org.jetbrains.contract</groupId> <artifactId>contract</artifactId> <version>1.2.4</version> </dependency> ``` Gradle dependencies: ``` implementation 'org.jetbrains.contract:contract:1.2.4' ``` Now, we can define the bank account class and use the 'Contracts for Java' to define the constraints. ```java import org.jetbrains.contract.Requires; import org.jetbrains.contract.Ensures; public class BankAccount { private double balance; public BankAccount(double initialBalance) { this.balance = initialBalance; } @Requires("amount > 0") @Ensures("balance >= old(balance)") public void deposit(double amount) { balance += amount; } @Requires("amount > 0 && amount <= balance") @Ensures("balance == old(balance) - amount") public void withdraw(double amount) { balance -= amount; } public double getBalance() { return balance; } } ``` In the above examples, we used the prefix conditions and rear conditions of the method of `@reques` and@ENSURES` to define the method.`@Requires` Annotation is used to define the pre -factor conditions, which specifies the constraints of the passing parameters.`@ENSURES` Annotation is used to define the rear conditions, which specifies the constraints after the method execution. In the `DEPOSIT` method, we used the` @Requires ("amount> 0") to define the pre -conditions that must be greater than 0, and use the `@NSURES (" Balance> = OLD (BALANCE) ")))`To define the balance of the balance after the deposit must be greater than the rear conditions of the previous balance. Similarly, in the `withdraw` method, we used the` @Requires ("amount> 0 && amount <= Balance") `to define the front conditions that must be greater than 0 and less than equal to the balance, and use the We can also use the@invariant` annotation to define the class without variables. This is the constraints that must be maintained in the entire class. ```java import org.jetbrains.contract.Invariant; @Invariant("balance >= 0") public class BankAccount { // ... } ``` In the above example, we used the `@invariant (" Balance> = 0 ")` to define a class that must be greater than or equal to 0. By using the 'Contracts for Java' framework, we can express the constraints of the code more clearly and verify it during runtime.This helps us write more robust, maintenance and reliable Java code. Note: This case is only the purpose of demonstration. In the actual production environment, more complicated constraints and more comprehensive testing may be required.

Grizzly asynchronous HTTP client is a powerful and efficient Java class library that is specially used to handle HTTP requests and responses.This article will introduce the best practice to develop the Java class library using the Grizzly asynchronous HTTP client.We will cover the following topics: configure the GRIZZly client, send HTTP requests, process HTTP response, and abnormal processing. ### Configure Grizzly client Before using the Grizzly asynchronous HTTP client, you need to configure the client first.The following code shows how to configure the Grizzly client: ```java import org.glassfish.grizzly.http.client.*; import java.util.concurrent.TimeUnit; public class GrizzlyClientConfig { public static HttpClient configure() { HttpClientConfig clientConfig = new HttpClientConfig(); clientConfig.setConnectTimeout(5000, TimeUnit.MILLISECONDS); clientConfig.setReadTimeout(5000, TimeUnit.MILLISECONDS); clientConfig.setTcpNoDelay(true); return HttpClientFactory.createHttpClien t(clientConfig); } } ``` The above code is created by creating the `httpclientconfig` object, and sets up connection timeout time, read timeout, and disable the Nagle algorithm.Then, use the `httpclientfactory.createhttpclient () method to create and return a` httpclient` object. ### Send HTTP request It is very simple to send the HTTP request through the Grizzly asynchronous HTTP client.The following code shows how to send GET requests and process the response: ```java import org.glassfish.grizzly.http.*; import org.glassfish.grizzly.http.client.*; public class GrizzlyClientExample { public static void sendGetRequest() { HttpClient httpClient = GrizzlyClientConfig.configure(); HttpGetRequestBuilder requestBuilder = HttpClient.create().prepareGet("https://example.com"); httpClient.send(requestBuilder.build(), new HttpTransactionCompletionHandler() { @Override public void onComplete(HttpTransactionContext httpTransactionContext) throws Exception { HttpResponsePacket response = httpTransactionContext.getResponsePacket(); // Treatment response } @Override public void onError(HttpTransactionContext httpTransactionContext, Throwable throwable) { // Process errors } }); } } ``` In the above code, we first call the `grizzlyclientconfig.configure ()` method to configure the Grizzly client and create a HTTP get request.Then, send the request by calling the method of `httpclient.send ()`, and use the `httptransactionCompltingHandler` to process the completion and error of the request.At the time of completion, we can obtain the HTTP response from the object of the `httptRANSACTIONTEXTEXTExt` and perform the corresponding processing. ### treatment HTTP response When we receive an HTTP response, we need to handle accordingly according to actual needs.The following code shows how to deal with the response: ```java import org.glassfish.grizzly.http.HttpResponsePacket; public class GrizzlyClientExample { public static void processResponse(HttpResponsePacket response) { // Treatment response } } ``` In the above code, the `httpresponsepacket` object provides different attributes and methods for accessing response.You can obtain and process the status code, response head, text, etc. of the response in actual needs. ### abnormal processing When using Grizzly asynchronous HTTP client, many abnormalities may be encountered, such as connection timeout, reading timeout, and network errors.The following code shows how to deal with exceptions: ```java import org.glassfish.grizzly.http.HttpTransactionContext; public class GrizzlyClientExample { public static void handleError(HttpTransactionContext httpTransactionContext, Throwable throwable) { // Treatment abnormalities } } ``` In the above code, when an abnormalities occur, the `Throwable` object will be passed to the method of the` handleer () method.You can handle abnormalities according to the actual situation and take appropriate measures, such as re -try to send a request or record log. This article introduces the best practice of developing the Java class library using the Grizzly asynchronous HTTP client.By correcting the Grizzly client, sending HTTP requests, processing HTTP response, and abnormal processing, you can easily write high -efficiency and reliable HTTP client code.Hope this article will help you!

The Marked framework is a tool to analyze and convey the Markdown text, which is widely used in the Java library.This article will introduce the principles and implementation technology of the MARKED framework, and provide some related Java code examples. 1. Overview of the MARKED framework The Marked framework is an excellent open source project. It can easily display and share documents by converting Markdown text into HTML, Latex and other formats.The framework supports a wide range of Markdown syntax marks and provides rich configuration options to meet different needs. Second, the principle of the MARKED framework The core principle of the Marked framework is based on the collaborative work of parsers and renderers.It decomposes the input Markdown text into a grammatical unit, and recognizes and analyzes the grammatical mark through parsers.The parser follows a series of parsing rules, such as title, paragraphs, lists, links, etc., and converts it into the corresponding HTML or other formats.The rendereer then rendered these resolution results into the final output. Third, the implementation technology of the MARKED framework 1. The implementation of the parser: The Marked framework adopts a line -by -line analysis method to read every line of text and use a series of regular expressions for matching and analysis, thereby identifying and processing the MarkDown syntax mark. Here are a simple analyzer example to analyze and handle the title mark of Markdown: ```java import java.util.regex.Matcher; import java.util.regex.Pattern; public class Parser { private static final Pattern HEADER_PATTERN = Pattern.compile("^(#+)(.*)"); public String parseHeader(String line) { Matcher matcher = HEADER_PATTERN.matcher(line); if (matcher.find()) { int level = matcher.group (1) .length (); // title level String content = matcher.group (2) .trim (); // Title content return "<h" + level + ">" + content + "</h" + level + ">"; } return null; } } ``` 2. Realization of the renderer: The MARKED framework provides the default renderer to convert the Markdown syntax of the parser to HTML format.The rendereer traverses the resolution results returned by the parser and performs the corresponding HTML rendering based on different types. The following is a simple example of rendering device. It is used to convert the title marking of Markdown to the title element of HTML: ```java public class Renderer { public String renderHeader(String content, int level) { return "<h" + level + ">" + content + "</h" + level + ">"; } } ``` Finally, combine the parseper and renderer to complete the analysis and conversion of the entire Markdown text: ```java public class Marked { private Parser parser; private Renderer renderer; public Marked() { this.parser = new Parser(); this.renderer = new Renderer(); } public String parse(String markdown) { StringBuilder result = new StringBuilder(); String[] lines = markdown.split(" "); for (String line : lines) { String header = parser.parseHeader(line); if (header != null) { result.append(header); } } return result.toString(); } } ``` Fourth, summary The Marked framework uses the collaborative work of parsers and renderers to realize the conversion from the Markdown text to HTML and other formats.It recognizes and parsed the Markdown syntax mark, and then renders the resolution results into a final output by the renderer.This method of analysis and conversion provides us with efficient and flexible tools to show and share Markdown documents.

Optimize the performance and response time of the FM HTTP framework in the Java library overview: The FM HTTP framework is a Java -based open source library for handling HTTP requests and responses.However, with the increase of application scale and load, performance and response time have become the focus of attention.This article will introduce some optimization skills and practice to improve the performance and response time of the FM HTTP framework. introduction: In modern application development, network communication is an indispensable part.The HTTP protocol is one of the most widely used network protocols to transmit data between clients and servers.The FM HTTP framework provides a simple and powerful way to handle the HTTP request and response. However, in the case of processing large -scale requests and high concurrency loads, performance and response time may become bottlenecks.Therefore, optimizing the performance and response time of the FM HTTP framework is essential to provide efficient services. Optimization skills: Here are some skills to optimize the performance and response time of the FM HTTP framework: 1. Using connection pool: Creating and release connection is an expensive operation.Using the connection pool can reuse the created connection to avoid the establishment and release of the overhead of the connection, thereby improving performance and response time. ```java // Use the connection pool to create a connection ConnectionPool connectionPool = new ConnectionPool(); Connection connection = connectionPool.getConnection(); // Process request Response response = connection.execute(request); // Release connection connectionPool.releaseConnection(connection); ``` 2. Use multi -threading: processing concurrent requests by using multi -threads can increase throughput and response time.You can use Java's Executor framework to achieve multi -threaded processing, such as using a thread pool to manage and reuse threads. ```java ExecutorService executor = Executors.newFixedThreadPool(10); // Submit the task to the thread pool executor.execute(() -> { // Process request Response response = connection.execute(request); }); // Close the thread pool executor.shutdown(); ``` 3. Use cache: For some unchanged data, cache can use cache to improve performance and response time.You can use Java's memory cache library, such as Caffeine or EHCACHE to slowly respond in memory. ```java Cache<String, Response> cache = Caffeine.newBuilder().maximumSize(1000).build(); // Find the cache Response cachedResponse = cache.getIfPresent(request.getUrl()); if (cachedResponse != null) { // Use the cache response return cachedResponse; } else { // Process request Response response = connection.execute(request); // Storage to cache cache.put(request.getUrl(), response); return response; } ``` 4. Reduce unnecessary network requests: When processing HTTP requests, you can reduce network overhead by merging multiple requests or reduce unnecessary requests, thereby increasing performance and response time. ```java // Merge multiple requests RequestBatch requestBatch = new RequestBatch(); requestBatch.add(request1); requestBatch.add(request2); requestBatch.add(request3); BatchResponse batchResponse = connection.executeBatch(requestBatch); // Reduce unnecessary requests if (condition) { // Process request Response response = connection.execute(request); // ... } ``` Summarize: By using the techniques such as connection pools, multi -thread, cache, and optimization network requests, we can optimize the performance and response time of the FM HTTP framework in the Java class library.Through these optimizations, we can improve the throughput and user experience of the application, so as to better meet the needs in different scenarios.I hope the optimization skills provided in this article will be helpful to you.

The FM HTTP framework (FM HTTP Framework) is an open source framework widely used in the Java library to build a high -performance HTTP application.It provides a simple and elegant way to handle HTTP requests and responses, and it is easy to integrate into existing Java projects.This article will introduce the characteristics and usage of the FM HTTP framework and provide some Java code examples. 1. Framework characteristics The FM HTTP framework has the following characteristics and functions: 1.1 High performance: The FM HTTP framework uses asynchronous non -blocking IO models, which can process a large number of concurrent requests to provide excellent performance. 1.2 Lightweight: The entire framework is very lightweight. It only relies on a small number of third -party libraries and is easy to deploy and maintain. 1.3 Easy -to -use: FM HTTP framework provides simple APIs, enabling developers to quickly build HTTP applications. 1.4 Scalability: The framework provides a flexible expansion mechanism that can easily customize and enhance the function of the framework. 1.5 Support multiple HTTP request methods: FM HTTP framework supports common HTTP request methods, such as Get, POST, PUT, Delete, etc. 1.6 Routing function: The framework provides the routing function. You can forward the request to a specific processor function according to the URI mode. 2. Use examples Below is a simple example, demonstrating how to use the FM HTTP framework to process the HTTP request. First, you need to add the FM HTTP framework to the Maven or Gradle project: ```java dependencies { // Maven <dependency> <groupId>io.github.fm-kt</groupId> <artifactId>fm-http</artifactId> <version>1.0.0</version> </dependency> // Gradle implementation 'io.github.fm-kt:fm-http:1.0.0' } ``` Next, create a HTTP server in the Java class and define the function of processing requests: ```java import io.github.fmkt.HttpServer; import io.github.fmkt.Request; import io.github.fmkt.Response; public class MyHttpServer { public static void main(String[] args) { HttpServer server = new HttpServer(); // Define the routing rules, forward the "/hello" get request to the handlehello function server.get("/hello", MyHttpServer::handleHello); // Start the http server server.start(8080); } public static void handleHello(Request request, Response response) { // Get the request parameter String name = request.queryParam("name"); // Construction response content String responseBody = "Hello, " + (name != null ? name : "World") + "!"; // Send response response.send(200, responseBody); } } ``` In the above example, we created a HTTP server and defined a routing rule to forward the GET request of "/Hello" to the Handlehello function.The handlehello function receives a Request object and a Response object. Through these two objects, you can obtain and send the HTTP request and response.In this example, we constructed a simple response based on the request parameter, and used the Response object to send it back to the client. Through the above simple examples, we can see the simplicity and ease of use and flexibility of the FM HTTP framework.Developers can use the FM HTTP framework to quickly build high -performance HTTP applications according to their own needs. Summarize This article introduces the characteristics and usage of the FM HTTP framework, and provides a simple example to demonstrate how to use the framework to build an HTTP application.It is hoped that through the introduction of this article, readers can learn more about the FM HTTP framework and apply its advantages in actual projects.

Java Ee JMS API Introduction JMS (Java Message Service) API in Java EEERPRISE EDITION is a message transmission framework for building distributed applications.It provides a reliable way to pass messages between different applications without having to pay attention to the details of the bottom layer. JMS is a message transmission mechanism based on the Message Queue model.It uses the decoupling of producers (Producer) and consumers to achieve message transmission.Producers are responsible for creating and sending messages, and consumers are responsible for receiving and processing messages.This decoupling mechanism makes applications easier to expand and collaborate. Java Ee provides a standard message transmission solution on the JMS API as a standard message transmission solution on the Java platform.Here are some main concepts and components in the JMS API: 1. Connection Factory: Connect the factory to create a connection with JMS providers.It is a factory that creates a connection object. Applications can use connection objects to communicate with JMS providers. 2. Connection: Connection represents a communication link between the application and the JMS provider.Applications can create a session through the connection object. 3. SESSION: Session is the context between producers and consumers.It is responsible for creating messages, sending messages, and receiving and processing messages. 4. Destination: Destination is the end of message transmission, which can be queue or topic.The queue is a Point-to-Point model, and a message can only be accepted by one consumer; the theme is a PUBLISH-SUBSCRIBE model, and a message can be received by multiple subscribers. 5. Producer: Producers are responsible for creating and sending messages.It can send the message to the destination through the session object. 6. Consume: Consumers are responsible for receiving and processing messages.It can receive messages from the destination through the session object. The following is a simple example code that shows how to send and receive messages with Java Ee JMS API: // Send a message ConnectionFactory ConnectionFactory = New ActiveMQConnectionFactory (); // Create connecting the factory Connection connection = connectionFactory.createconnection (); // Create a connection Session session = connection.createSession (false, session.auto_acknowledge); // Destination Destination = Session.createqueue ("Myqueue"); // Create a queue destination MessageProducer Producer = Session.createProducer (DESTINATION); // Create a producer TextMessage Message = Session.createtextMessage ("Hello, JMS!"); // Create text messages Producer.send (MESSAGE); // Send message // Receive messages MessageConsumer Consumer = Session.createConsumer (Destination); // Create consumers connection.start (); // Start the connection Message ReceivedMessage = Consumer.Receive (); // Receive messages if (receivedMessage instanceof TextMessage) { TextMessage textMessage = (TextMessage) receivedMessage; String text = textMessage.getText(); System.out.println("Received message: " + text); } session.close (); // Close the session connection.close (); // Close the connection Through this example code, we can see the basic process of sending and receiving messages using JMS API.First, we create a connection factory and use it to create a connection.Then, we created a session and created a destination (queue) in the session.Next, we use the session to create a producer and send a message.Finally, we create a consumer and receive messages. To sum up, the JMS API is a powerful and flexible message transmission framework in Java EE, which can help us build distributed applications with scalable and collaborative jobs.With the JMS API, we can easily implement the message sending and receiving, thereby effectively decoupled different modules of the application.

Use the Circe YAML framework to implement the data durable in the Java class library Overview: Data persistence is a very important concept in computer science.It refers to saving the data into a certain lasting storage medium so that the data can be retained when the application is closed or restored.In Java development, we can use various persistent technologies, such as relational databases, file storage, cache, etc.This article will introduce how to use the Circe YAML framework to achieve the duration of data in the Java class library to provide readers with an example code to better understand. Introduction to Circe YAML framework: Circe YAML is a Java library that is used to sequence the Java object to YAML format and the derivative sequences into the Java object.YAML (Yaml Ain't Markup Language) is a human readable data serialization format, which is very suitable for configuration files and cross -language data exchange. Example scene: Suppose we are developing a student information management system. In this system, we need to keep the students' basic information for a long time.This information includes students' names, age, gender, etc. Example code: First, we need to introduce the dependency item of the Circe Yaml library in the pom.xml file of the project: ``` <dependency> <groupId>io.github.java-yaml</groupId> <artifactId>circe-yaml</artifactId> <version>1.14</version> </dependency> ``` Then we create a Student class to represent student information: ```java public class Student { private String name; private int age; private String gender; // Eliminate the constructor, Getter, and Setter method @Override public String toString() { return "Student{" + "name='" + name + '\'' + ", age=" + age + ", gender='" + gender + '\'' + '}'; } } ``` Next, we write a method to save student information to the yaml file: ```java import io.circe.syntax._ import io.circe.yaml.syntax._ import java.nio.file.Files; import java.nio.file.Paths; public class DataPersistenceUtil { public static void saveStudentToFile(Student student, String filePath) throws IOException { String yaml = student.asJson.asYaml.spaces2(); Files.write(Paths.get(filePath), yaml.getBytes()); System.out.println ("Student information has been saved to the file:" + filepath); } } ``` Finally, we can call the above method in the main program to save student information: ```java public class Main { public static void main(String[] args) { Student Student = New Student ("Zhang San", 18, "Male"); try { DataPersistenceUtil.saveStudentToFile(student, "student.yaml"); } catch (IOException e) { e.printStackTrace(); } } } ``` When we run the above code, student information will be saved in a Yaml file named "Student.yaml".After viewing the content of the file, we can see the following: ```yaml name: "Zhang San" age: 18 Gender: "Man" ``` In this way, we successfully use the Circe Yaml framework to achieve the durable data in the Java library. Summarize: In this article, we introduced how to use the Circe YAML framework to achieve durable data in the Java library.By introducing the dependency item of the Circe Yaml library, create a Java object and serialize it into YAML format, we can save the data into the Yaml file.This method can easily persist data and deepen and read when needed.It is hoped that this article will help readers when realizing data persistence.

Use the 'Contracts for Java' framework in the Java class library for code contract management Summary: 'Contracts for Java' is a powerful Java class library for managing and maintaining code contracts in the development process.Through the use of contracts, developers can specify the expected input and output, behavior and constraints in the code, and ensure the correctness and reliability of the code.This article introduces the basic concept and usage of the 'Contracts for Java' framework, and provides some Java code examples to demonstrate how to use the framework. Introduction: Code contract is a way to define and execute code behavior during the development process.They allow developers to insert the predefined rules and restrictions in the code to ensure that the code meets these constraints during runtime.The 'Contracts for Java' framework provides a simple and flexible method to implement code contracts, and automatically generates and verify these contracts during the development process. The benefits of using the 'Contracts for Java' framework: 1. Improve the accuracy and reliability of the code: By constraining the code constraints, the behavior of the code can be ensured that the behavior of the code is consistent with expectations, and the occurrence of errors and abnormalities can be reduced. 2. Provide automated contract generation and verification: 'Contracts for Java' framework provides automated contract generation and verification functions, saving the time and energy of manual writing and checking the contract. 3. Improve the maintenance of code: By specifying the contract in the code, the readability and maintenance of the code can be improved, and the cost of code maintenance can be reduced. Example: Below is a simple Java code example, which shows how to define and verify the contract when using the 'Contracts for Java' framework. ```java import org.contract4j5.contract.Contract; import org.contract4j5.contract.Invariant; import org.contract4j5.contract.Pre; import org.contract4j5.errors.ContractError; public class Calculator { @Pre("args.length == 2") @Invariant("result > 0") public int divide(int dividend, int divisor) { if (divisor == 0) { throw new IllegalArgumentException("Divisor cannot be zero"); } return dividend / divisor; } public static void main(String[] args) { Calculator calculator = new Calculator(); try { int result = calculator.divide(10, 0); System.out.println("Result: " + result); } catch (ContractError e) { System.out.println("Contract error: " + e.getMessage()); } } } ``` In the above example, the DIVIDE method in the Calculator class has a front condition and an unchanged condition.The front conditions use @Pre annotation definition, specifying the method to accept the requirements of the two parameters.The constant condition is defined by @invariant annotations, which stipulates that the return result must be greater than zero.In the implementation of the method, if the division is zero, a IlLegalalargumentedException will be thrown out. Through the definition of contracts in the above examples, we can verify whether the contract is violated by triggering the Contracterror abnormality.In the main method, we created a Calculator object and called the DIVIDE method.Since we pass a parameter with zero divisions, it will violate the front conditions and cause the ContraCterror abnormality. Summarize: 'Contracts for Java' framework is a powerful and flexible tool for implementing code contracts during the development of Java.By defining and verifying contracts, developers can improve the reliability and maintenance of code and reduce potential errors and abnormalities.To use this framework, you only need to add a corresponding annotation to the code to define the contract, and verify the correctness of the contract by triggering the Contracterror abnormality.This framework is a useful tool for any developer who needs to increase code reliability.