集合转换成数组
List<String> c = new ArrayList<String>();
c.add(null);
c.add("two");
c.add("three");
c.add("");
c.add("four");
c.add("five");
System.out.println(c);
System.out.println(c.size());
Object[] array=c.toArray();
String[] array1=c.toArray(new String[5]);
System.out.println(Arrays.toString(array1));
System.out.println(Arrays.toString(array));
数组转换成集合
String[] array=new String[]{"one","two","three"};
List<String> list = Arrays.asList(array);
System.out.println(list);
//list.add("cc");
list.set(0, "1");
System.out.println(list);
System.out.println(Arrays.asList(array));
List<String> list1 = new ArrayList<String>(list);
System.out.println(list1);
list1.add("cc");
System.out.println(list1);
System.out.println(list);