Java

1. Create base class In a project, we often have to build a base class of entity classes with common methods to improve code reuse.Suppose each table has field IDs and username, and each table requires a similar crud method (such as checking XX

Use the String.CompareTo method:The return value of CompareTo () is int, which is the size of the corresponding character (ASCII code order) first1. If string equals return value 02. If the first character and the first character of the parameter

1, first to write a PDF tool class, and related tools 2. PDF of the required jar package Itext is a Java component that generates PDF reportsFreemarker is based on a template to generate text output com.itextpdf itext-asian 5

Before Java 2, Java provided the ad hoc class. For example: vectors, stacks, dictionaries (Dictionary), hash tables (Hashtable) These classes (data structures) are used to store and manipulate groups of objects. Although these classes are useful,

Recently in the study of the JVM, found that with the virtual machine at the bottom of the understanding of Java multithreading also has a new understanding of the original a small synchronized keyword in the Shia. decided to put their own Java

Turn: 79390980 ext: 78931420The AVA backend generates tokens (tokens) to validate the client and prevent duplicate submissions1. Overview: In Web projects, the server and the front end often need to interact with data, sometimes due to the slow

Multithreading and concurrency issues are an essential part of any Java interview. If you want to get the front desk information for any stock investment bank, you should prepare a lot of questions about multithreading. Multithreading and

Front Desk: Support Five sets of templates, can be switched in the backgroundSystem Introduction:1. The website backstage uses the mainstream SSM framework JSP JSTL, the website backstage uses the Freemaker static template engine to generate the

Exception Description:2018-06-0614:24:02.932 ERROR 17364---[ange-worker-#42]. c.d.d.p.griddhtpartitionsexchangefuture:failed to reinitialize local PA Rtitions (preloading'll be stopped): ...java.lang.IndexOutOfBoundsException: Index

Java API and the object classJava API -applicatio (application),Programming (program),Interface (interface)The Java API is the class that is provided to us in the JDK, which encapsulates the underlying code implementation, and we don't need to be

method area: class information, class variables (static variables and constants), methods   heap: object, member variable   stacks: local variables   (1) When the program is run, the bytecode file is loaded first through the

1. Paint (Graphics g)In Java drawing, the most common use is paint (Graphics g) {... Content... } method to get the brush, and then use containers such as jpanel as the canvas, the content is rendered within the jframe, in many cases this approach

1. Why Use NiONIO was created to enable Java programmers to implement high-speed I/O without having to write custom native code. NIO transfers the most time-consuming I/O operations (that is, the fill and fetch buffers) back to the operating system,

Java Data types Basic data type (lowercase is generally used) Characteristics In addition to the value without any identification, 1=1 Immutable data types Within scope, local stacks are stored

Looking back on the past, I think each program ape is locked in a transparent cage, limiting the thinking, blind eyes, wasted years without knowing, if not try to go out is a lifetime can not perceive the existence of the cage. This cage is the

many friends in the career change is very cautious, in many people's eyes to learn Java development is to knock code just, this idea erased a lot of people want to switch enthusiasm. In fact, the Java engineer is not a dull job, it has a variety of

Using JSON for network download1. Download the JSON string:(1) Encapsulate URLs into URLs: url url=new url ("url");(2) using the URL to open http:httpurlconnection conn= (httpurlconnection) ulr.openconnection ();(3) Start connection: Conn.connect ();

Knowledge points: Front-end tabular data, invoke background interface, export Excel file data, use to Apache POI interfacePOI provides the ability for Java programs to read and write to Microsoft Office format files. (1) Introduction of POI and file

ObjectiveJava Multi-threaded classification has written 21 multi-threaded articles, 21 Articles of a lot of content, personally think, learning, the more content, the more miscellaneous knowledge, the more need to carry out a profound summary, so as

The general direction of Java is JAVAEE,JAVAEE not just socket programming, including 13 core technologies.Core APIs and components for Java EEThe Java EE platform consists of a suite of services, application interfaces (APIs), and protocols that