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
Added by Benjigga on Thu, 10 Mar 2022 18:34:12 +0200
1: Abstract classes and interfaces
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 ...
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 ...
Added by bb_xpress on Tue, 08 Mar 2022 15:41:53 +0200
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.
1. Import JDBC and mysql dependencies
In POM XML import t ...
Added by jredwilli on Tue, 08 Mar 2022 07:59:29 +0200
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
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
<select id="findAll" resultType="com.qcby.entity.User"> ...
Added by cemeteryridge on Sun, 06 Mar 2022 03:39:13 +0200
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 ...
Added by lances on Sat, 05 Mar 2022 05:41:15 +0200
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 ...
Added by azul85 on Fri, 04 Mar 2022 22:13:33 +0200
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 ...
Added by edcaru on Mon, 28 Feb 2022 13:45:45 +0200
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 ...
Added by iamtheironman on Thu, 24 Feb 2022 18:46:33 +0200