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java process control 1, Scanner object Basic grammar Get the input string through the next() and nextLine() methods of the Scanner class. Before reading, we generally need to use hasNext and hasNextLine to judge whether there is still input data public static void main(String[] args) { //Create a scanner object to receive keyboard data ...

As we all know, the class name of the external top-level class must be the same as the class file name, and only public and default can be used. The internal class refers to defining another class inside the external class. The class name does not need to be the same as the file name. Internal classes can be static, public, default, protected a ...

2, Multithreading 2.1 creation method of multithreading 1) Inherit Thread class 2) Implement the Runable interface 3) Implement Callable interface /** * callable Method to create a thread * Return value * * Communication between threads (wait/notify) */ public class Test1 { public static void main(String[] args) { // //St ...

generic paradigm Generic type is essentially a parameterized type, that is, the operated data type is specified as a parameter, that is, the type is parameterized from the original specific type, and then the specific type is passed in during use / call. This parameter type can be used in classes, methods and interfaces, including generic class ...

User interaction scanner Basic knowledge of Scanner definition The Scanner scanner can scan the data entered by the user on the console through the Scanner class Basic grammar Scanner sc = new Scanner(System.in); Scanner gets the string entered by the console Method 1: next() method example package com.lan.scanner; import java.util.S ...

Thread collaboration Thread communication Application scenario: producer and consumer issues Suppose that only one product can be stored in the warehouse, the producer puts the produced products into the warehouse, and the consumer takes the products from the warehouse for consumptionIf there is no product in the warehouse, the producer wi ...

introduction It records the concept of multithreading, inheriting Thread, realizing Runnable, Thread sleep, Thread safety problems and solutions, multithread communication problems and Thread pool. Overview of multithreading technology Threads and processes process It refers to an application running in memory, and each process has an inde ...

generic paradigm 1. Benefits of generics At compile time, check the type of added elements to improve securityWhen the ClassCastException of the runtime is transferred to the compilation time, it becomes a compilation failure.It reduces the number of type conversions and improves efficiency 2. Precautions 1. Interface list, public class Has ...

Making QR code requires introducing google jar <dependency> <groupId>com.google.zxing</groupId> <artifactId>javase</artifactId> <version>3.3.0</version> </dependency> QR code generation: /** * @param text QR code storage information * @param width ...

catalogue 1, Demand analysis 2, Preparatory work 1. Prepare the development environment 2. Prepare the database 3. Prepare for outsourcing 3, Specific steps 1. Open IDEA and create an empty project  2. After completion, import a new module 3. Import the outsourcing jar package to be used by JDBC. 4, Code implementation 1. Inte ...