Basic knowledge of JDBC - overview, PreparedStatement, data table operation

JDBC overview Data persistence Persistence: save data to a power down storage device for later use. In most cases, especially for enterprise applications, data persistence means saving the data in memory to the hard disk for "solidification", and the implementation process of persistence is mostly completed through various relat ...

Posted by Aikon on Mon, 29 Nov 2021 06:58:18 +0100

[Chapter 18] - Maven Eclipse's b2b2c e-commerce technology summary of Spring Cloud live mall

Maven Eclipse Eclipse provides a good plug-in   m2eclipse   , the plug-in can integrate Maven and Eclipse. Maven is included in the latest Eclipse. Let's open windows - > preferences. If so, the following screen will appear: Here are some features of m2eclipse: You can run Maven's target files on the Eclipse environment.You can ...

Posted by Mr Chew on Wed, 24 Nov 2021 05:10:09 +0100

Three characteristics of Java object-oriented -- Inheritance

inherit Commonness extraction In inheritance, a subclass is a parent, that is, a subclass can be treated as a parent For example, the parent class is an employee, the child class is a lecturer, and the lecturer is an employee Define parent class: (the definition of ordinary class is the same) public class parent class name{ //...... } D ...

Posted by ethan.whitt on Fri, 19 Nov 2021 18:27:27 +0100

MapReduce programming -- merging and de duplication of files

catalogue 1, Problem description 2, Specific code 3, Specific operation 1, Problem description Merge multiple input files, eliminate the duplicate contents, and output the duplicated contents to one file.         Main idea: according to the process characteristics of reduce, the input value set will be automatically ...

Posted by PHP-Nut on Tue, 16 Nov 2021 11:53:04 +0100

Learning of IO flow -- the overall framework and use of IO flow

IO flow learning (II) - the overall framework and use of IO flow Stream operation I/O is the abbreviation of input/output, that is, the data transmission between processing devices, and the transmission process is called "flow"; And java provides standard methods to read and write data, and the input and output is for programs ( ...

Posted by chenggn on Tue, 09 Nov 2021 20:50:48 +0100

Go deep into the bottom! Iterative traversal and traversal of binary tree

① Traversal mode and concept of binary tree Preorder traversal: traverse according to the head left right method, first output the head, then output the left, and finally output the right.                 According to the above figure, the preceding traversal should ...

Posted by possiblyB9 on Sat, 23 Oct 2021 16:56:42 +0200

Shopping cart group homework

1. Team members and task assignment classfull nametaskNetwork 2014LAN suyuResponsible for coding related work: coding specification, object-oriented design, function designNetwork 2014Liu YuhengResponsible for writing blog related work: preliminary investigation, blog production 2. Preliminary investigation (taking Jingdong Mall interface ...

Posted by yoda699 on Thu, 21 Oct 2021 17:19:00 +0200

Learn JavaDay04 on October 14, 2021

JavaDay04 Java environment construction JDK download and installation Uninstall the original environment and configure the JDK Delete the original environment variable, system – > environment variable – > java_ Home file location where the value is found – > delete – > then delete the environment variable ...

Posted by CostaKapo on Thu, 14 Oct 2021 21:47:35 +0200

Try with resources to automatically close resources

try catch finally For all java developers, closing resources in a finally block of code is a familiar approach. Part of exception handling is to ensure that all kinds of resources in the code block are closed and effectively released. Once the code in the try catch statement block throws an exception, the previous workflow will change. try { ...

Posted by dekeb55 on Mon, 11 Oct 2021 03:32:38 +0200

Implementation of multithreading

Implementation of multithreading 1. Inherit Thread class     (1) define a class to inherit Thread and override the run() method;     (2) create subclass objects of Thread class;     (3) call start() to start a new thread. //The main thread and the custom thread execute concurrently public class th ...

Posted by lukegw on Sat, 09 Oct 2021 11:05:44 +0200