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File: an abstract representation of files and folders in java Construction method: public File(String pathname) Create a new File instance by converting the given pathname string to an abstract pathname. If the given string is an empty string, the result is an empty abstract pathname. public File(String parent,String child) Create a new Fi ...

1. What is a business? Database transaction is simply to operate several different SQL statements as a whole, either all successful or all failed. It has four characteristics: atomicity, consistency, isolation and persistence. Spring transaction is a transaction processing mechanism encapsulated in database transaction. It has two manageme ...

SpringMVC First of all, let's learn about the classic MVC mode. The full name of MVC is Model View Controller. M refers to business model and data model, V refers to user interface and C refers to controller. The purpose of using MVC is to separate the implementation codes of M and V, so that the same program can use different expressions. ...

Introduction to Spring framework Overview of Spring framework Spring is an open source design level framework, which solves the loose coupling problem between business logic layer and other layers. Therefore, it runs through the whole system application with the idea of interface oriented programming. Spring is a lightweight java develo ...

First, what is MyBatis? MyBatis is a state-of-the-art persistence framework that supports custom SQL, stored procedures, and advanced mapping. MyBatis eliminates almost all JDBC code and manually setting parameters and retrieving results. MyBatis can use simple XML or Annotations to configure and map primitives, mapping interfaces, and Java PO ...

2022Java learning notes 33 (object-oriented enhancement: inheritance, @ Override rewrite annotation) 1, What is inheritance 1. Inheritance is a relationship between classes 2. Multiple classes inherit a single class, and multiple classes can use the properties and behaviors of a single class 3. Multiple classes are called subclasses (derived c ...

1, What is a Servlet servlet is one of the Java EE specifications, which is the interface Servlet is one of the three major components of Java web. The three major components are: servlet program, filter and Listener listener. Servlet is a Java applet running on the server. It can receive the request sent by the client and respond to the da ...

1. Code block overview Code block: also known as initialization block, it is a member of a class, similar to a method. It encapsulates logical statements in the method body and is surrounded by {};And methods: 1. No method name, no return value, no parameter, only method body;2. It is not called explicitly through an object or class, but im ...

Chapter 15 reflection mechanism You need to master the specified structure of obtaining Class instances, creating runtime Class objects, and calling runtime classes. Reflection overview Reflection is the key to being regarded as a dynamic language. Reflection mechanism allows programs to obtain the internal information of any class with the ...

Spring Realize the decoupling between classes: facilitate the management between classes 1. Light weight: it occupies less resources during operation, has high operation efficiency, and does not rely on other jar s 2. Decoupling: spring provides ioc control inversion, which enables the container to manage objects and their dependencies. The ...