foreach，for,Iterator 比较

@Test
    public void testListJ8() {
        //first,genarate a  list
        List<TOJ8> list = new ArrayList<TOJ8>();
        Random r = new Random(100);
        for(int i = 0;i<100;i++){
            TOJ8 t= new TOJ8();
            t.name = "Student"+i;
            t.sorce = r.nextInt();
            list.add(t);
        }
        Long start = System.currentTimeMillis();
        list.forEach((t)->{
//            System.out.println(t.name+":"+t.sorce);
        });
        Long end = System.currentTimeMillis();
        System.out.println ("for each spent " + (end-start)+"ms");
        for(TOJ8 toj8 : list){
//            System.out.println(toj8.name+":"+toj8.sorce);
        }
        Long end1 = System.currentTimeMillis();
        System.out.println ("for spent " + (end1-end)+"ms");

        Iterator<TOJ8> it = list.iterator();
        while(it.hasNext()){
            TOJ8 t = it.next();
//            System.out.println(t.name+":"+t.sorce);
        }
        Long end2 = System.currentTimeMillis();
        System.out.println ("Iterator spent " + (end2-end1)+"ms");


    }

    class TOJ8 {
        private String name;
        private int sorce;

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public int getSorce() {
            return sorce;
        }

        public void setSorce(int sorce) {
            this.sorce = sorce;
        }
    }

结果:
for each spent 53ms
for spent 0ms
Iterator spent 0ms