Java

1. Data types in JavaData type: base type and reference typeBasic type: Numeric, character, BooleanNumeric: integer types and floating-point typesReference type: Class, interface, arrayBasic data typesFour class/Eight class basic types are defined

Invert a binary tree. 4 / 2 7/\ /1 3 6 9To 4 / 7 2/\ /9 6 3 1Trivia:This problem is inspired by this original tweets by Max Howell:Problem Solving Ideas:Recursive, Java implementation is as follows: Public

Reverses the number in an integer and returns 0 (marked as a 32-bit integer) when the inverted integer overflows.Problem Solving Ideas:The Java implementation is as follows: public int Reverseinteger (int n) {Boolean Isneg = n >= 0? false:true;

This article mainly tests the use of quantifiers and quantifier suffixes, and the results of the tests are placed behind the test methods as comments.Package Regularexpression;import Java.util.regex.matcher;import Java.util.regex.pattern;import

Java.io.IOException:This Archive has already been finishedAt Org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream.finish (ziparchiveoutputstream.java:406)At Com.xunge.AESFileEncoder.unzip (aesfileencoder.java:212)At

java.util.logging.LogManagerthe manages the internal Logger hierarchy, and initiates Logger the configuration of the ' s, either through the Configu Ration class or configuration file.There is a single instantiated in the LogManager whole JVM. It's

Table of Contents Configuration Class Configuration File The Java Logging API can be configured in both ways: Via a configuration class. Via a configuration file. The initialization of the configuration is taken

Find the total area covered by and rectilinear rectangles in a 2D plane.Each rectangle was defined by its bottom left corner and top right corner as shown in the figure.Assume the total area is never beyond the maximum possible value of

Table of Contents Log level Logger Hierarchy Logmanager In this text I'll try to give your an overview of the java.util.logging API. Hopefully it is easier to understand, the individual components once your understand the big

JSON, JSON for data exchange, json for data exchange 1. JSON 1.1. JSON 1.1.1.What is JSON JSON is the Javascript Object Notation, which is a mainstream data exchange format. The reason for its wide application is determined by its ease of

SpringMVC notes (3)-BeanNameUrlHandlerMapping, handlermapping BeanNameUrlHandlerMapping is similar to SimpleUrlHandlerMapping in the previous section. The difference is that the former bean name is used as a url, while the latter needs to configure

Five things you don't know about Java object serialization (1)   A few years ago, when I was writing an application in Java with a software team, I realized the benefits of having a little more knowledge about Java object serialization than the

In struts2 development, some functions need to be configured in struts. xml1. General package   /Primer/success. jsp /Primer/formSuccess. jsp  2. How to Set forwarding and redirection for a package  

Singleton mode in java Singleton mode: instances with only one object in the context.Application Scenario: Only one scenario is required for a thread pool, cache, and other systems. Three Common Singleton modes:1. Delayed Loading public class

Design Mode Study Notes-decoration ModeDefinition: dynamically extends the functions of an object without changing the original class file or using inheritance. It creates a packaging object, that is, decoration, to package a real object. UML

Java utilities (Date Processing and http)/*** Returns the day of the year based on the date.* @ Param date* @ Return*/Public static int orderDate (String dateStr ){If (dateStr = null | dateStr. trim (). length () = 0) return 0;Int dateSum = 0;Int

Java design pattern-Proxy pattern Proxy mode provides a Proxy or placeholder for an object to control access to the object. There are several application scenarios:   RemoteProxy provides a local representation of an object in different address

Observer mode-Java Design Mode Observer mode definition: defines one-to-many dependencies between objects. In this way, when an object changes its state, all its dependent persons will receive notifications and update them automatically. See: The

Use Spring container in Servlet Filter Definefilter, ImplementationApplicationContextAwareInterface: Public class CacheFilter implements Filter, ApplicationContextAware {private static ApplicationContext ctx; // It must be declared as static @

Implementation and consideration of the String class For strings, it is sometimes difficult for us to compare and directly copy or define them into integer or other variables. This is a problem in C language, in C ++, we provide a type of special