List和ArrayList之间转换的例子

package Test01;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Test01 {
	public static void main(String[] args){
		a();
		b();
		c();
	}
	
	@SuppressWarnings("unchecked")
	public static void a(){
		@SuppressWarnings("rawtypes")
		List list = new ArrayList();
		list.add(0);
		list.add(1);
		list.add(3);
		list.add(4);
		System.out.println(list);
		System.out.println(list.getClass());
	}
	
	public static void b(){
		Double []arr=new Double[]{1.0,2.0,3.0,null};
		@SuppressWarnings("rawtypes")
		List list = Arrays.asList(arr);
		System.out.println(list);
		System.out.println(list.getClass());
	}
	
	@SuppressWarnings("unchecked")
	public static void c(){
		Double []arr=new Double[]{1.0,2.0,3.0,null};
		@SuppressWarnings("rawtypes")
		List list = Arrays.asList(arr);
		@SuppressWarnings("rawtypes")
		ArrayList arrayList = new ArrayList();
		for (int i = 0; i < list.size(); i++) {
			arrayList.add(list.get(i));
		}
		System.out.println(arrayList);
		System.out.println(arrayList.getClass());
	}
}

 

代码运行后控制台输出结果如下：