LinkedList与ArrayList的性能比较

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package jiben.data;import java.util.ArrayList;import java.util.LinkedList;import java.util.List;import java.util.ListIterator;public class Listsd {public static void main(String[] args) {// TODO Auto-generated method stub//添加记录是int sum = 10000000;//移除记录数int rm = 300;//修改记录数int cha = 30000;System.out.println("start add "+sum/10000+"W rows;  rm "+300+" rows;cha "+cha+" rows");System.out.println("--------------------------------------");System.out.println("");System.out.println("");long  n = System.nanoTime();List<String> al = new ArrayList<String>(); Listsd.test(al,sum,rm,cha,n);n = System.nanoTime();al = new LinkedList<String>();Listsd.test(al,sum,rm,cha,n);}public static void test(List<String> al,int sum,int rm,int cha,long  n){if(al instanceof ArrayList)System.out.println("ArrayList");elseSystem.out.println("LinkedList");System.out.println("init time(ns) "+(System.nanoTime()-n));long s = System.currentTimeMillis();for(int i=0;i<sum;i++){al.add("hello");}System.out.println("add time "+(System.currentTimeMillis()-s));s = System.currentTimeMillis();ListIterator<String> it = al.listIterator();while(it.hasNext()){it.next();}System.out.println("read time "+(System.currentTimeMillis()-s));s = System.currentTimeMillis();for(int i=0;i<cha;i++)al.set(i, "word");System.out.println("change rows time "+(System.currentTimeMillis()-s));s = System.currentTimeMillis();for(int i=0;i<rm;i++)al.remove(i);System.out.println("remove rows time "+(System.currentTimeMillis()-s));s = System.currentTimeMillis();al.clear();System.out.println("clear time "+(System.currentTimeMillis()-s));System.out.println("--------------------------------------");System.out.println("");System.out.println("");}}

console结果：

start add 1000W rows; rm 300 rows;cha 30000 rows
--------------------------------------

ArrayList
init time(ns) 39822
add time 160
read time 11
change rows time 3
remove rows time 3163
clear time 12
--------------------------------------

LinkedList
init time(ns) 756210
add time 2831
read time 79
change rows time 644
remove rows time 0
clear time 66
--------------------------------------

结论选择List的时候

1.如果集合特别长没有删除元素的操作，首选ArrayList.否则选择LinkedList.ArrayList删除元素耗费时间远大于LinkedList.

2.集合不是很大，选择ArrayList(init、add、read的时间很短)

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