java-杨浩东 1507084225

[DreamYHD]

1 删除羊

        Iterator<String> sheepss = sheeps.iterator();
        int i = 0;
                方法一
         while (sheepss.hasNext()) {

         System.out.println(sheepss.next());
         i++;
         if (i > 2) break;
              }

        for(Iterator sheepss1 = sheeps.iterator();sheepss1.hasNext();){
            System.out.println(sheepss1.next());

        }
               方法二
        for (Object str : sheeps) {
        if (i < 3) {
            System.out.println(str.toString());
        }
        i++; 
           //i>3的时候删去前面的
        }

            方法三
          for(int i=0;i<sheeps.size();i++){ System.out.println(sheeps.get(i));

          } System.out.println("删除后三个");

         for(int i=0;i<sheeps.size()-3;i++){
          System.out.println(sheeps.get(i));

          } System.out.println("删除前两个"); 
             for(int  i=sheeps.size()-1;i>sheeps.size()-4;i--){
          System.out.println(sheeps.get(i));

          }


    }

2 Thread Runnable

     //Runnable 代码被多个线程共享；
    public void run() {
        while (num > 0) {
            num--;
            System.out.println(Thread.currentThread().getName() + "减少了一" + "  "
                    + num);
        }

    }
           MyThread a = new MyThread();
           Thread b = new Thread(a, "one");
           Thread c = new Thread(a, "two");
           Thread d = new Thread(a, "three");
             b.start();
             c.start();
             d.start();
    //Thread    JAVA单继承方式
       public void run() {
        while (num > 0) {
            num--;
            System.out.println(name + "减少了一" + "  " + num);

        }
    }
        Mythread a = new Mythread("first");
        Mythread b = new Mythread("second");
        Mythread c = new Mythread("third");
             a.start();
             b.start();
             c.start();

3写入文件我真 i

            for (int i = 0; i < 10; i++) {

                file = new File(manyfile, "helloworld" + i + ".txt");
                if (!file.exists()) {
                    file.createNewFile();

                }
            }
        for (int i = 0; i <= 9; i++) {
            file = new File(manyfile, "helloworld" + i + ".txt");
            OutputStream os = null;
            try {
                os = new FileOutputStream(file);
                String s = "我真" + i;

                try {
                    os.write(s.getBytes());
                } catch (NumberFormatException | IOException e) {
                    e.printStackTrace();
                }
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } finally {
                try {
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

        }