类实现接口
只要实现的某一个接口, 那么就必须实现接口中所有的属性和方法
错误示例：
interface PersonInterface { name: string; say(): void; } class Person implements PersonInterface { name: string = 'BNTang'; } let p = new Person(); p.say();
正确示例：
interface PersonInterface { name: string; say(): void; } class Person implements PersonInterface { name: string = 'BNTang'; say(): void { console.log(`我的名字叫:${this.name}`); } } let p = new Person(); p.say();
接口继承类
定义一个 Person 类如下：
class Person { name: string = 'BNTang'; age: number = 18; say(): void { console.log(`name = ${this.name}, age = ${this.age}`); } }
- 只要一个接口继承了某个类, 那么就会继承这个类中所有的属性和方法
- 但是只会继承属性和方法的
声明, 不会继承属性和方法的实现
class Person { name: string = 'BNTang'; age: number = 18; say(): void { console.log(`name = ${this.name}, age = ${this.age}`); } } interface PersonInterface extends Person { gender: string; } class Student implements PersonInterface { gender: string = 'male'; name: string = 'zs'; age: number = 18; say(): void { console.log(`name = ${this.name}, age = ${this.age}, gender = ${this.gender}`); } } let stu = new Student(); stu.say();
- 如果接口继承的类中包含了
protected的属性和方法, 那么就只有这个类的子类才能实现这个接口
包含
protected属性的情况
错误示例：
class Person { protected name: string = 'BNTang'; age: number = 18; say(): void { console.log(`name = ${this.name}, age = ${this.age}`); } } interface PersonInterface extends Person { gender: string; } class Student implements PersonInterface { gender: string = 'male'; name: string = 'zs'; age: number = 18; say(): void { console.log(`name = ${this.name}, age = ${this.age}, gender = ${this.gender}`); } } let stu = new Student(); stu.say();
正确示例：
class Person { protected name: string = 'BNTang'; age: number = 18; say(): void { console.log(`name = ${this.name}, age = ${this.age}`); } } interface PersonInterface extends Person { gender: string; } class Student extends Person implements PersonInterface { gender: string = 'male'; name: string = 'zs'; age: number = 18; say(): void { console.log(`name = ${this.name}, age = ${this.age}, gender = ${this.gender}`); } } let stu = new Student(); stu.say();
包含
protected方法的情况
错误示例：
class Person { name: string = 'BNTang'; age: number = 18; protected say(): void { console.log(`name = ${this.name}, age = ${this.age}`); } } interface PersonInterface extends Person { gender: string; } class Student implements PersonInterface { gender: string = 'male'; name: string = 'zs'; age: number = 18; say(): void { console.log(`name = ${this.name}, age = ${this.age}, gender = ${this.gender}`); } } let stu = new Student(); stu.say();
正确示例：
class Person { name: string = 'BNTang'; age: number = 18; protected say(): void { console.log(`name = ${this.name}, age = ${this.age}`); } } interface PersonInterface extends Person { gender: string; } class Student extends Person implements PersonInterface { gender: string = 'male'; name: string = 'zs'; age: number = 18; say(): void { console.log(`name = ${this.name}, age = ${this.age}, gender = ${this.gender}`); } } let stu = new Student(); stu.say();
最后
本期结束咱们下次再见👋~
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