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catalog User login case requirements Development steps: 1. Create project, configuration file and import jar package. 2. Write logged in login.html Page. 3. Create the database userlogin and the table user. 4. Create a package com.qgl . 'domain'. Create an entity class user. The entity class user c ...

Hadoop's Trample Notes (1) Deploying a hadoop cluster on Centos7 Environmental Science Machine 1(hadoop1-ali) Ali Cloud (CentOS 7.3) 120.26.173.104 Machine 2(hadoop2-hw) Huawei Cloud (CentOS 7.4) 114.116.233.156 Where the first server serves as a namenode and the second serves as a datanode Modify hostname and hostfile Execute on two machines ...

Enumeration is a new data type in JDK 1.5. With enumeration, we can well describe some specific business scenarios, such as spring, summer, autumn and winter in a year, Monday to Sunday in a week, and various colors, as well as some state information, such as error codes. Enumeration type not only exists in Java language, but also can be found ...

Chapter 1 JavaScript Basics 1. What is JavaScript? HTML+CSS completes the static page display, but to complete better and more complex user interaction and data interaction and display, you need to use JavaScript. JavaScript is an object-based and event driven scripting language with security performance 2. Features of JavaScript a. You can add ...

Article catalog Business scenario Practice mode The first way The second way code implementation Function extension Distributed high availability other target Realize the change from ordinary website to short website reference resources:Design short URL system How are short links designed? Get ...

Learning any technology is a two-step process: Setting up the environment helloworld I'm no exception. I'll do it directly. 1, RocketMQ installation 1. Documents Official website http://rocketmq.apache.org GitHub https://github.com/apache/rocketmq 2. Download wget https://mirror.bit.edu.cn/apache/rocketmq/4.7.0/rocketmq-all-4.7.0-bin-rele ...

Playing with Stream in Java 8 By litesky Link: http://www.jianshu.com/p/11c925cdba50 I believe you have heard about Java8 Stream, but you may not be able to use it or you are not familiar with it. This article will take you to use it from scratch, step by step, and lead you to the peak of Stream. Operator What are operators? Operator is a k ...

Ajax class notes jQuery simplifies js, mainly dom operation Find it (selector) Do it (dom operation method) selector Basic selector $("div") $("#div") $(".cls") Level selector $("div span"): a selector connected with spaces to find descendants $("div > span"): use t ...

0. Directory 1,JDBC 2. Import the jar package of MySQL JDBC for the project 3. Initialize driver 4. Establish a connection to the database 5. Create Statement 6. Execute SQL statement 7. Close connection 8. Use try with resource to automatically close the connection 9. Reference link 1,JDBC JDBC ...

1.Junit unit test Test classification: 1. Black box test: do not need to write code, do not see the process of program execution, input some parameters, and see the expected results. 2. White box test: you need to write code, you can see the process of program execution, enter some parameters, and see ...