oca java 7

Java based on the time of day to obtain the time between the first 7 days and the number of days after the query timePackage Com.kugou.schedu.service;import Java.text.parseexception;import Java.text.simpledateformat;import Java.util.calendar;import Java.util.date;import Java.util.gregoriancalendar;import Org.springframework.beans.factory.annotation.autowired;import Org.springframework.stereotype.component;i

java. Lang. Enum class. Because Java does not support multi-inheritance, enumeration objects cannot inherit other classes. Public Interface Behaviour {void print (); string getinfo ();} public Enum color implements behaviour {red ("red", 1), Green ("green", 2 ), blank ("white", 3), yello ("yellow", 4); // member variable private string name; private int index; // constructor private color (string name, int

Java BASICS (7: interface, variable scope, and parameter transfer)I,Interface Java does not allow a subclass to have multiple direct parent classes, that is, any subclass can have only one direct parent class. However, a class can implement multiple interfaces, that is, the interface Name List of the defined class can contain one or more interface names, so as to

[Valid Java] 7. Give priority to generic methods, and define tivejava Package cn. xf. cp. ch02.item27; import java. util. hashSet; import java. util. set; public class Union {/*** this method generates a warning * @ param s1 * @ param s2 * @ return */public static Set union1 (Set s1, Set s2) {Set result = new HashSet (

rely on its abstraction; abstraction should not depend on detail; detail should be dependent on abstraction. That is, for interface programming, do not program for implementation.4, the interface isolation principle "INTERFACE segregation PRINCIPLE": Establish a single interface, do not set up a huge bloated interface, as far as possible to refine the interface, the interface of the method as little as possible.5. Dimitri law "low of DEMETER": Cohesion Poly.6. Open Close PRINCIPLE: A software e

stack element is:" +item); + } - $ Public Static voidpop () { $ if(!IsEmpty ()) { - if(Queue1.isempty ()) { - while(Queue2.size () >1){ the Queue1.offer (Queue2.poll ()); - }WuyiSystem.out.println ("Out of stack element:" +Queue2.poll ()); the}Else{ - while(Queue1.size () >1){ Wu Queue2.offer (Queue1.poll ()); - } AboutSystem.out.println ("Out of stack element:" +Queue1.poll ()); $ }

about the classes it relies on. That is to say, for a dependent class, no matter how complex the logic, as far as possible to encapsulate the logic inside the class, outside the public method provided, not to disclose any information.6. Open Close PRINCIPLE: A software entity such as classes, modules, and functions should be open to extensions and closed for modification.7, combination/aggregation multiplexing principle "composition/aggregation reuse

7. Java graphical interface design-null layout of layout manager (empty layout) and graphical null Reprinted: http://blog.csdn.net/liujun13579/article/details/7774267 Generally, containers use the default Layout mode. However, if you need to specify the size and position of each component accurately, an empty layout is required. Operation Method: 1) First, use the setLayout (null) statement to set the con

, perform 4. Otherwise, perform 3.Create a new working Queue (thread, refer to the previous section). If it is successful, return directly. If it fails, perform step 4.If the thread pool is running and the task is successfully added to the thread pool queue, perform Step 5. Otherwise, perform Step 7.If the thread pool has been closed or the thread pool size is 0, perform 6. Otherwise, return directly.If the thread pool is closed, a denial policy is ex

Java multi-thread programming 7: deadlock (source code) Source code downloadIn multi-threaded programming, thread deadlock is also an interesting issue. However, the possibility of deadlock is very small. For this reason, we may not be very familiar with it. But deadlock is not unimportant, because it does exist and will appear in our program at any time. Many of my friends encountered a similar programming

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Java programmers learn php-7.Map is called Associated arrays such as: nbsp; $ map ['BJ '] = 'Beijing'; nbsp; $ map ['sh'] = 'Shanghai '; traverse the associated array: nbsp; foreach ($ mapas $ abbr = gt; $ full_name) { nbsp; nb java programmers learn php-7. map is called an associated array. For example: $ Map [

Java 7 allows us to catch many different exceptions in the same catch statement block, also known as multiple exception captures. Before Java7, we might want to do this: try { Execute code This may throw 1 of the 3 exceptions below. catch (SQLException e) {Logger.log (e); catch (IOException e) {Logger.log (e); catch (Exception e) {Logger.severe (e);}As you can see above, both SQLException and IOExcept

Java programmers learn php-7.Map is called Associated arrays such as: nbsp; $ map [BJ] Beijing; nbsp; $ map [SH] Shanghai; traverse this Associated array: nbsp; foreach ($ mapas $ abbr gt; $ full_name) { nbsp; nbsp java programmers learn php-7. map is called an associated array. For example: $ Map ['BJ '] = 'Bei

This article will briefly introduce the Java Socket Direct protocol (Sockets Direct PROTOCOL,SDP) introduced in the Java 7 SDK, and this new technology is a very exciting breakthrough. If you want to native access to InfiniBand's remote Direct memory access (Sqlremote direct Memory ACCESS,RDMA), SDP enables ultra-high performance computing (Ultra high Performance

reclaiming the object's memory.5. SummaryThe level of JAVA4 references is from highest to lowest:Strong references > Soft references > Weak references > virtual referencesTake a look at the differences between them in garbage collection:When the garbage collector recycles, some objects are reclaimed and some are not recycled. The garbage collector marks the surviving object from the root object, and then reclaims some unreachable objects and some referenced objects, and if you are not familiar

Maybe we often pay attention to the characteristics of each Set in practical applications or interviews. For example, the Set cannot store duplicate elements, and cannot maintain the insertion and size order, map sets store key-value pairs and so on. However, if you want to learn Java well or have a higher goal and be proficient in Java, it is far from enough. In fact, we still need to know more about the c

Polymorphism of three object-oriented features -- Java note (7)Polymorphism: the type of an object that has multiple forms of compilation is determined by the type used to declare the variable, the type of the runtime is determined by the object that is actually assigned to the variable. If the compilation type and runtime type are different, there will be a multi-state example: copy code 1 class Preson {2}

, Samoyed run once, short tail cat run once).This method can not be fully guaranteed, it is possible to run the husky several times. Two Kazakhstan continued 6.The method is added in the test class:1 Public classThreadyieldextendsThread {2 @Override3 Public voidrun () {4 for(intx = 0; x ) {5System.out.println (GetName () + ":" +x);6 Thread.yield ();7 }8 }9}Daemon ThreadsPublic final void Setdaemon (Boolean on): marks the thr

Review database MySQL backup and recovery:show databases;User spdb1;Show tables;Perform a backup in the Mysql/bin directory:./mysqldump-u root-p spdb1 >/home/spdb1.bakYou will be prompted to enter the password for the user root.Delete a database drop databases spdb1;Recovery database: Mysql-u root-p database name You need to create a new empty database before recovering the database, otherwise error. Create a new user under/mysql/bin: the Create database name;SSH Introduction:SSH (Secure Shell)