The main function of the interface is to achieve unified access, which is to use the interface when creating an object, [Interface name] [Object name] = new [ Classes that implement interfaces], so that you can create new objects according to which class you want to use. You don’t need to change the original code. It’s just like your USB interface. You can read whatever you plug in. This is the principle. (Recommended study: java course)
As you asked, there is a method1 method. If I use an interface, I can use one.method1();, right? In that case, my new a(); uses the method of a, and new b() uses the method of b
Isn’t this convenient?
This is called unified access, because the method name of the class you implement this interface is the same, but the implementation content is different
If I use the interface to define the object, can I achieve unified access? Yet?
The interface is mainly for multiple classes to implement it. If there is only one class, of course there is no need for an interface. Think of it this way, I make a USB interface with a read() abstract method, and then the mp3 class implements it. , U disk class implementation, mobile hard disk class implementation, so when I use it, I use USB a=new [class name];
This way a.read(); If I write U disk in the class name, read U Disk, write mp3 and read mp3, and this name can be read from the properties file, you can use whichever one you write, haha.
Interface is a specification
Software development is mostly a collaborative work: electrical appliances and sockets are completed by different people,With the interface, everyone They can work separately, and all work according to the interface, and they can be easily integrated together after each has finished their work. Testing of various parts is also more convenient.
The interface can quickly separate work content during the development process.
For example, when the caller needs a function when writing business logic, it may be database access or complex calculation, but his work focuses on implementing business logic and does not want to separate his energy from the underlying implementation, then He only needs to implement an interface first and define the specification, and then he can continue with his business logic code. The implementer can make specific implementations based on this interface specification.
In this way, by using the interface, the work content can be quickly separated to achieve the purpose of parallel work of the team
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