java 技术提升，复习，总结（二）

java 技术提升，复习，总结（二）

接上篇反射：

数组的反射,同样看代码理解：

int [] a1 = new int[]{1,2,3};
		int [] a2 = new int[4];
		int[][] a3 = new int[2][3];
		String [] a4 = new String[]{"a","b","c"};
		System.out.println(a1.getClass() == a2.getClass());
		System.out.println(a1.getClass() == a4.getClass());
		System.out.println(a1.getClass() == a3.getClass());
		System.out.println(a1.getClass().getName());
		System.out.println(a1.getClass().getSuperclass().getName());
		System.out.println(a4.getClass().getSuperclass().getName());
		
		Object aObj1 = a1;
		Object aObj2 = a4;
		//Object[] aObj3 = a1;
		Object[] aObj4 = a3;
		Object[] aObj5 = a4;
		
		System.out.println(a1);
		System.out.println(a4);
		System.out.println(Arrays.asList(a1));
		System.out.println(Arrays.asList(a4));	
		
		printObject(a4);
		
		printObject("xyz");

	private static void printObject(Object obj) {
		Class clazz = obj.getClass();
		if(clazz.isArray()){
			int len = Array.getLength(obj);
			for(int i=0;i
  
   


   
4：ArrayList与HashSet

   






   
                Collection collections = new HashSet();
		ReflectPoint pt1 = new ReflectPoint(3,3);
		ReflectPoint pt2 = new ReflectPoint(5,5);
		ReflectPoint pt3 = new ReflectPoint(3,3);	

		collections.add(pt1);
		collections.add(pt2);
		collections.add(pt3);
		collections.add(pt1);	
   
              System.out.println(collections.size());

   
      public class ReflectPoint {
	
	
	private int x;
	public int y;

   


   

   
	
	public ReflectPoint(int x, int y) {
		super();
		this.x = x;
		this.y = y;
	}
	
	
	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + x;
		result = prime * result + y;
		return result;
	}


	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		final ReflectPoint other = (ReflectPoint) obj;
		if (x != other.x)
			return false;
		if (y != other.y)
			return false;
		return true;
	}


}