ArrayList list = new ArrayList(4);
list.add("123");
list.add("345435");
System.out.println(list);
Map<String,Object> parasMap = new HashMap<String,Object>(5);
parasMap.put("insurants",list);
parasMap.put("familyOrderNo","345345");
parasMap.put("reason","123123");
System.out.println(parasMap);
parasMap.remove("reason");
System.out.println(parasMap);
list集合 指定大小:有幾個值就設置多少
map集合指定大小:有N個Key,就設置: N/0.75+1 的大小