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[TOC] I. fsimage and edit files 1. Basic concepts txid: namenode gives a unique id for each operation event (add, delete, and change operation), which is called txid. Generally, txid is automatically increased from 0. For each additional operation, txid is automatically increased by 1. fsimage: It is a mirror file of the metadata of namenode i ...

1 set the syntax format of html file xsd file Write xsd file according to the properties of POJO. for example <?xml version="1.0" encoding="UTF-8" ?> <schema xmlns="http://www.w3.org/2001/XMLSchema" targetNamespace="http://www.zhangyh.com/schema/user" elementFormDefault="qualified"> <element name="user"> ...

IOC container IOC containers, sometimes called dependency injection (DI). Through the dependencies defined by the object itself, these dependencies are injected into the bean when it is created. This process is contrary to our normal design. We usually have a new object in the object, which is our program control management object. In spring, w ...

SpringBoot e-commerce project mall (20k+star) address: https://github.com/macrozheng/mall abstract Spring Cloud OpenFeign is a declarative service invocation tool, which integrates Ribbon and Hystrix and has load balancing and service fault tolerance functions. This article will introduce its usage in detail. Feign introduction Feign is a decl ...

This is the first article introduced and used by gin. I. brief introduction Gin's official statement is as follows: Gin is a web framework written in Go (Golang). It features a martini-like API with much better performance, up to 40 times faster thanks to httprouter. If you need performance and good productivity, you will love Gin. Official ...

demand Adaptive size text: Design sketch: In project development, developers lay out some pages with text according to a set of sizes provided by UI personnel. Often less consideration will be given to some data limits, resulting in the problem of screen adaptation. For example: Text (or numeric) length is variable, such as experience value, nu ...

Application of Spring AOP Notification xml version Create a new maven project Project Structure Diagram pom.xml file <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLo ...

I believe you have a general idea of ActiveMQ through your last blog post. So this blog will lead you step by step to actually operate our ActiveMQ. The main contents of this paper are as follows: 1. Introduction of ActiveMQ Terminology and API 2.ActiveMQ Text Message Processing 3.ActiveMQ Object Message Processing Now that we have to le ...

Preface After climbing for two days, the pit finally came up. It was very simple to see what others wrote. When they wrote, they had various problems. There were many SSO articles on the Internet, and when they wrote, they had various problems (they were too dishy). Make a note. It's easy to check later. For the OAuth2 Authentication and Author ...

Preface Sprboot's project has not been updated for half a month since it was put down. Finally, I can write happily when I am free. Before we configure mybatis with multiple data sources, we need to do an email service. For example, when you register, you need to enter a validation code to verify. This validation code can be sent by mail. Of co ...