风韵少妇性饥渴推油按摩视频,国产69精品久久久久观看软件

Article Tags

Home

Technical Articles

Java

Best practices in Java Stream for finding elements and handling default situations

This article explores in-depth ways to efficiently find matching elements and elegantly handle unfinished cases in the Java Stream API. By combining filter(), findFirst() and ifPresentOrElse(), we can implement the search logic of traditional loops in a concise and declarative way, and execute preset default behavior when elements do not exist, thereby improving the readability and robustness of the code.

Aug 23, 2025 am 10:57 AM

Resolve AWS Java SDK EC2 connection reset and XML parsing error: Switch to asynchronous client

This article aims to resolve the errors "Unable to execute HTTP request: Connection reset" and "XMLStreamException: ParseError" when accessing EC2 services using the AWS Java SDK. By analyzing the problem phenomenon, point out the possible limitations of synchronous clients when handling potential large responses, and provide a solution: replace Amazon EC2ClientBuilder with Amazon EC2AsyncClientBuilder to optimize the stability and responsive processing capabilities of EC2 API calls.

Aug 23, 2025 am 10:45 AM

Calculate the number of days, hours, minutes and seconds between two dates and times in Java

This article describes how to calculate the number of days, hours, minutes, and seconds between two dates and times using Java 8 and later. It covers parsing date and time strings, time zone processing, and calculating time difference using Duration class. The article provides clear code examples and steps to help developers deal with calculation needs in specific date and time formats.

Aug 23, 2025 am 10:36 AM

How to use flatMap in the Java Stream API

flatMap is used in JavaStreamAPI to map elements into streams and flatten nested structures, suitable for processing collections in collections. 1. It applies a function that returns Stream to each element and merges all substreams into a single stream; 2. It is often used to flatten List to a single-layer Stream; 3. It can extract collection data in an object, such as getting all hobbies from List; 4. Unlike map, flatMap supports one-to-many or zero conversion; 5. It does not skip empty sets, but it does not produce any elements; 6. Only flatten one layer of nesting. For example, using flatMap(List::stream) can merge multi-layer lists into single-layer streams and eventually collect them through collect

Aug 23, 2025 am 10:34 AM

How to parse a CSV file in Java

Parsing CSV files can be implemented in Java in many ways, and it is recommended to use third-party libraries to handle complex situations. 1. Use the OpenCSV library (recommended): First add Maven or Gradle dependencies, then read all rows through CSVReader and iterate over the output, or use CsvToBeanBuilder to map CSV rows to Java objects (such as Person class). Make sure that the CSV header matches the field name. 2. Use Java built-in class: read line by line through BufferedReader and split fields with split(","), but this method cannot handle quotation commas correctly, and it only works for simple CSV files without commas. 3

Aug 23, 2025 am 10:19 AM

Use the Stream API to find the maximum value of a Map in a List

This article describes how to use the Java Stream API to find objects with the maximum length in a List containing a HashMap. First, it is recommended to use custom objects instead of HashMap to improve code readability and type safety. Then, we explain in detail how to find a single largest element using Stream.max() and Collections.max(), and how to find multiple elements with the same maximum length using groupingBy() and collect(). Finally, a method is provided to avoid creating intermediate maps and remind readers of the importance of interface-oriented programming.

Aug 23, 2025 am 10:18 AM

Couchbase and string pool: Practice for optimizing large-scale data storage

This article explores how to use the concept of string pooling to optimize memory usage when storing large amounts of data using Couchbase. For JSON document scenarios that store a large number of duplicate strings, this article will introduce how to implement string residency through a custom Jackson deserializer, thereby effectively reducing the memory usage of Couchbase cache.

Aug 23, 2025 am 09:51 AM

Spring Boot JPA data retrieval null pointer exception check and resolution

This article aims to help developers diagnose and resolve data retrieval null pointer exceptions caused by the mismatch between the entity class field and the database column name in Spring Boot JPA project. By analyzing problem code, entity class definitions and Repository interfaces, we provide detailed troubleshooting steps and solutions to ensure that data can be loaded correctly from the database into the application.

Aug 23, 2025 am 09:48 AM

How to copy a file in Java

TheeasiestandmostreliablewaytocopyafileinJavaisusingFiles.copy()fromthejava.nio.filepackage.2.AlwaysuseStandardCopyOption.REPLACE_EXISTINGtooverwritethedestinationfileifitexists,otherwiseaFileAlreadyExistsExceptionwillbethrown.3.Alternativestream-bas

Aug 23, 2025 am 09:37 AM

Compare version numbers using Java: Beyond regular expressions

This article introduces an effective way to compare version numbers using Java code that avoids the complexity and limitations of regular expressions. Version comparisons can be easily performed by parsing the version number into an array of integers and implementing the Comparable interface, and solve problems that may arise when using string comparisons directly, such as "4" < "10".

Aug 23, 2025 am 09:36 AM

Maestro UI test run error: NoSuchMethodError Solution

This article aims to resolve the java.lang.NoSuchMethodError: java.io.InputStream.readAllBytes()[B] error encountered when using Maestro for Flutter Application UI testing. By analyzing the error message, we determine that the root cause of the problem lies in JDK version conflicts and provide a clear solution: uninstall other JDK versions, keep only JDK 11, and ensure that Maestro is running properly.

Aug 23, 2025 am 09:33 AM

How to overload methods in Java

Method overloading allows multiple methods with the same name but different parameters in the same class. 1. Implemented by changing the number of parameters, such as add(inta,intb) and add(inta,intb,intc); 2. Implemented by changing the parameter type, such as add(doublea,doubleb) and add(Stringa,Stringb); 3. Implemented by changing the parameter order (presumably different types), such as show(inta,Stringb) and show(Stringa,intb); Overload does not depend on the return type, and the parameter list must be different, and the compiler selects the corresponding party according to the priority of precise matching, type promotion, automatic boxing, and variable parameters during compilation.

Aug 23, 2025 am 09:28 AM

Correct posture for merging string arrays in Java: Avoid null value traps and index management

This tutorial explores the common null value problems when merging two string arrays in Java. By analyzing the loop logic of errors, we reveal that improper index management is the key to data loss. The article provides a simple and efficient solution, leveraging the correct loop boundaries and clever index increment mechanism to ensure that all elements are copied correctly. In addition, it is also introduced to implement more optimized combination and consolidation strategies using advanced methods such as System.arraycopy.

Aug 23, 2025 am 09:18 AM

Java Concurrency: `ExecutorService` and Thread Pools Explained

ExecutorService is the core interface used in Java to simplify concurrent task management. It realizes asynchronous execution of tasks through thread pooling mechanisms to improve performance and resource utilization. 1. Using ExecutorService can avoid manually creating threads and decoupling task submission from execution; 2. Common thread pool types include newFixedThreadPool, newCachedThreadPool, newSingleThreadExecutor and newScheduledThreadPool, but it is recommended to explicitly use ThreadPoolExecutor in the production environment to accurately control core parameters; 3. Thread pool is operated by the worker.

Aug 23, 2025 am 09:17 AM

java Thread Pool