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title: javaEE(SSM) learning notes 4: dynamic SQL Dynamic SQL import [main function]: splice SQL clauses according to different conditions or different data to achieve similar programming effect in XML files. [main element (mark)]: Query criteria: single branch if; Multi branch choose... when... other Special treatment: where /trim Up ...

1: Abstract classes and interfaces abstract class 1. Abstraction is to abstract the common characteristics of a class of entities. The parent class provides some attributes and behaviors for the child class, and the child class implements specific behaviors according to business requirements. 2. Abstract classes are decorated with abstract. Su ...

SpringSecurity Related concepts Principal [user or device using the system or user logging in remotely from other systems, etc. in short, whoever uses the system is the principal.] Authentication [the authority management system confirms the identity of an entity and allows the entity to enter the system. In short, it means that the &quo ...

Personal profile The author is a junior from Heyuan. The following notes are some shallow experience of the author's self-study road. If there are mistakes, please correct them. In the future, we will continue to improve our notes to help more Java lovers get started. SpringBoot+JDBC 1. Import JDBC and mysql dependencies In POM XML import t ...

1, Preface Delayed tasks are widely used. Typical application scenarios of delayed tasks include automatic cancellation of orders when they timeout; Payment callback retry. Among them, the order overtime cancellation has idempotent property, and there is no need to consider the problem of repeated consumption; Payment callback retry needs to co ...

1, Configure the environment variable moven 2, MyBatis Getting started steps 1. Introduce dependency 2. Write entity user Dao User write field get set toString method Methods defined in UserDao 3. Write UserMapper in restore <mapper namespace="com.qcby.dao.UserDao"> <select id="findAll" resultType="com.qcby.entity.User"> ...

During this time, I received a task, which is to jar the project according to the module. The purpose is: 1. Package according to modules to facilitate upgrading 2. After the module is subcontracted, which module is modified, update the corresponding module separately. There is no need to worry about the abnormal operation of the project due ...

Preface: without any fancy preface, it is a basic and practical thing. 1. Introduction to listener What is a web listener? Web listener is a special class in Servlet, which can help developers monitor specific events in the web, such as the creation and destruction of ServletContext, httpsession and ServletRequest; Creation, destruction an ...

1. What is AOP? AOP is aspect oriented programming, which extends the method without modifying the source code!!! It solves the coupling of business When we usually write code, we will implement various methods in the control layer, but too much code writing will lead to code redundancy. How to solve this problem? Then you need to use the ...

SpringBoot SpringBoot has all the advantages of spring, such as open source, lightweight, non intrusive and so on. Spring's own inversion of control (IOC) and aspect oriented (AOP) programming are also the characteristics of SpringBoot. However, spring itself has unavoidable disadvantages. First, it is the heavyweight configuration. Variou ...