11-泛型

一：

注意：数据类型的安全性问题可以理解为避免了数据类型转换错误。

package com.example;
//?是通配符，object是任意类型，不写类型
class A<T>{
    private T age;
    private T name;

    public T getAge() {
        return age;
    }

    public void setAge(T age) {
        this.age = age;
    }

    public T getName() {
        return name;
    }

    public void setName(T name) {
        this.name = name;
    }
}
public class MyClass {
    public static void main(String[] args){
        A<String> a = new A<String>();
        a.setAge("100");
        a.setName("hello");
        System.out.println("name is :"+ a.getName() + ",age is :"+ a.getAge());
    }
}

二：通配符

三：泛型接口

package com.example;
interface a<T>{
    public abstract void say(T name);
}

class People implements a<String>{

    int b;

    public int getB() {
        return b;
    }

    public void setB(int b) {
        this.b = b;
    }

    @Override
    public void say(String name) {
        System.out.print(this.getB()+name);

    }
}

public class MyClass {
    public static void main(String[] args){
        People p = new People();
        p.b = 10;
        p.say("hello");
    }
}

四：泛型方法

package com.example;
class A {
    public <T>T tell(T t){
        System.out.println(t);
        return t;
    };
}
public class MyClass {
    public static void main(String[] args){
        A a = new A();
        a.tell("hello");
        a.tell(12);
    }
}

五：泛型数组

package com.example;

public class MyClass {
    public static void main(String[] args){
        String arr[] = {"i","am","zwzx"};
        tell(arr);
    }
    public static  <T>void tell(T arr[]){
        for (int i = 0 ;i <arr.length;i++){
            System.out.println(arr[i]);
        }
    }
}