Code training Camp--arraylist

Requirements: Remove duplicate elements from the ArrayList collection

Import Java.util.*;class arraylisttest{ Public Static void Main(string[] args) {ArrayList Al =NewArrayList (); Al.add ("1"); Al.add ("2"); Al.add ("1"); Al.add ("2"); Al.add ("1"); Al.add ("3"); Al.add ("4"); Al.add ("1");        SOP (AL);        ArrayList Newal = Singleelement (AL);        SOP (Newal); System. out. println ("Hello world!");//The next call in the loop in the iteration will be hasnext judged once} Public StaticArrayListsingleelement(ArrayList al) {ArrayList Newal =NewArrayList (); Iterator it = Al.iterator (); while(It.hasnext ()) {Object obj = It.next ();if(!newal.contains (obj))            {Newal.add (obj); }        }returnNewal; } Public Static void SOP(Object obj) {System. out. println (obj); }}

[1, 2, 1, 2, 1, 3, 4, 1]
[1, 2, 3, 4]
Hello world!

Example:

//list set determines whether the element is the same, based on the Equals method of the elementImportJava.util.*;class person{PrivateString name;Private intAge Person (String name,intAge) { This. name = name; This. Age = Age; } PublicStringGetName()    {returnName } Public int Getage()    {returnAge } Public Boolean equals(Object obj) {if(! (objinstanceofperson))return false;        Person P = (person) obj; System.out.println ( This. name+"......"+p.name);return  This. Name.equals (P.name) && This. age==p.age; }}

Class ArrayListTest2 { Public Static void SOP(Object obj) {System. out. println (obj); } Public Static void Main(string[] args) {ArrayList Al =NewArrayList ();//al.add (Object obj); Object obj = new Person ("Zhangsan", +);Al.add (NewPerson ("Zhangshan", -)); Al.add (NewPerson ("Lisi", A)); Al.add (NewPerson ("Wangwu", at)); Al.add (NewPerson ("Wangwu", at)); Al.add (NewPerson ("Alex", -)); Al.add (NewPerson ("Alex", -));            Al = Singleelemenet (AL); Sop"Remove"+al.remove (NewPerson ("Alex", -))); Iterator it = Al.iterator (); while(It.hasnext ())                 {Person P = (person) it.next (); SOP (P.getname () +"::"+p.getage ()); }        }

public    Static  ArrayList singleelemenet  (ArrayList al) {ArrayList Newal = new             ArrayList ();            Iterator it = Al.iterator (); while             (It.hasnext ())                {Object obj = It.next (); if                 (!newal.contains (obj))                {Newal.add (obj);        }} return  Newal; }

Lisi......zhangshan
Wangwu......zhangshan
Wangwu......lisi
Wangwu......zhangshan
Wangwu......lisi
Wangwu......wangwu
Alex......zhangshan
Alex......lisi
Alex......wangwu
Alex......zhangshan
Alex......lisi
Alex......wangwu
Alex......alex
Alex......zhangshan
Alex......lisi
Alex......wangwu
Alex......alex
Removetrue
Zhangshan::20
Lisi::22
Wangwu::23

Code training Camp--arraylist