Java泛型之特点

泛型类及特点

1. 泛型的类型参数可以是泛型类

class Cls1<T>{
	T a;
	public Cls1(T a){
		this.a = a;
	}
	public T getData(){
		return a;
	}
}
public class Test {
	public static void main(String[] args) {
		Cls1<Cls1<Integer>> cls1 = new Cls1<Cls1<Integer>>(new Cls1(100));
		System.out.println(cls1.getData().getData());
	}
}

2. 泛型类可以同时设置多个类型参数

class Cls1<T>{
	T a;
	public Cls1(T a){
		this.a = a;
	}
	public T getData(){
		return a;
	}
}

class Cls2<T, T2>{
	T a;
	T2 b;
	public Cls2(T a, T2 b){
		this.a = a;
		this.b = b;
	}
	public T getData(){
		return a;
	}
	public T2 getData2(){
		return b;
	}
}


public class Test {
	public static void main(String[] args) {
		Cls1<Integer> cls1 = new Cls1<Integer>(10);
		System.out.println(cls1.getData());
		
		Cls1<String> cls2 = new Cls1<String>("法外狂徒");
		System.out.println(cls2.getData());
		
		Cls2<Integer, String> cls3 = new Cls2<Integer, String>(100, "帅");
		System.out.println(cls3.getData());
		System.out.println(cls3.getData2());
		
		Cls2<Integer, Integer> cls4 = new Cls2<Integer, Integer>(100, 20);
		System.out.println(cls4.getData() + cls4.getData2());
	}
}

3. 泛型类可以继承泛型类

abstract class Cls1<T>{
	T a;
	public Cls1(T a){
		this.a = a;
	}
	public T getData(){
		return a;
	}
	abstract void printInfo();
}

class Cls2<T, T2> extends Cls1<T>{
	T a;
	T2 b;
	public Cls2(T a, T2 b){
		super(a);
		this.b = b;
	}
	public T2 getData2(){
		return b;
	}
	@Override
	void printInfo() {
		// TODO Auto-generated method stub
		System.out.println("输出");
	}
}


public class Test {
	public static void main(String[] args) {
		Cls2<Integer, String> cls2 = new Cls2<Integer, String>(10, "张三");
		System.out.println(cls2.getData() + cls2.getData2());
		cls2.printInfo();
	}
}

4. 泛型类可以实现泛型接口

abstract class Cls1<T>{
	T a;
	public Cls1(T a){
		this.a = a;
	}
	public T getData(){
		return a;
	}
	abstract void printInfo();
}

interface Cls3<T>{
	abstract void printInfoCls3(T t);
}

class Cls2<T, T2> extends Cls1<T> implements Cls3<T>{
	T a;
	T2 b;
	public Cls2(T a, T2 b){
		super(a);
		this.b = b;
	}
	public T2 getData2(){
		return b;
	}
	@Override
	void printInfo() {
		// TODO Auto-generated method stub
		System.out.println("输出");
	}
	public void printInfoCls3(T t) {
		// TODO Auto-generated method stub
		System.out.println(t);
	}
}

public class Test {
	public static void main(String[] args) {
		Cls2<Integer, String> cls2 = new Cls2<Integer, String>(10, "张三");
		System.out.println(cls2.getData() + cls2.getData2());
		cls2.printInfo();
		
		cls2.printInfoCls3(100);
	}
}