mcrypt_encrypt和mcrypt_decrypt是用來進行字符串加密解密的加油，希望課程對你有幫助。

public?class?SetTest?{

	public?Set<Course>?Set_CourseToSelect;
	public?Course?c;
	public?Course?e;
	public?Course[]?cc;
	public?Course[]?ee;
	public?SetTest()
	{
		Set_CourseToSelect=new??HashSet<Course>();
	}	
	public?void?Add()
	{
		//1.add():
		c=new?Course(1,"java");
		e=c;
		Set_CourseToSelect.add(c);
		//2.addAll():
		cc=new?Course[]{new?Course(2,"C"),new?Course(3,"C#")};
		ee=cc;
		Set_CourseToSelect.addAll(Arrays.asList(cc));
	}
	public?void?Remove()
	{
		//3.remove():
		//Set_CourseToSelect.remove(e);
		//4.removeAll():
		Set_CourseToSelect.removeAll(Arrays.asList(ee));
	}
	public?void?Get()
	{
		System.out.println("-----------------------");
		for(Course?c:Set_CourseToSelect)
		{
			System.out.println(c.id+":"+c.name);
		}
		
	}
	/**
	?*?@param?args
	?*/
	public?static?void?main(String[]?args)?
	{
	??//?TODO?Auto-generated?method?stub
?????????????SetTest?st=new?SetTest();
?????????????st.Add();
?????????????st.Remove();
?????????????st.Get();
?????????}
??}