为了增加说服力，每一种操作都可以设置重复次数，重复次数越大，求平均的结果越有说服力。这里根据情况设置了1或者10（见main函数的注释）。有时间同学可以设大一些。
先贴结果：
分别对比的是：add(); addlast(); get(); remove() 方法。
insert into arraylist for 10 times cost: 65 insert into linkedlist for 10 times cost: 170 insert into the last of arraylist for 10 times cost: 180 insert into the last of linkedlist for 10 times cost: 123 find from arraylist for 1 times cost: 3
结果分析：
add方法：对比性能较为明显：linkedlist的插入时间明显长一些。
addlast方法：区别不大：从尾部插入至linkedlist时间可能还要短一些（原因有待分析）。
get方法：linkedlist 性能差很多。
remove方法：linkedlist明显优于arraylist。
上一篇从源代码上做了二者简单的分析。这一篇编写单线程代码对比二者性能。
贴代码：
import java.util.ArrayList;
import java.util.LinkedList;
/**
* Created by aaashen on 2015/4/8.
*/
public class Vs {
private ArrayList alist = new ArrayList<Integer>();
private LinkedList llist = new LinkedList<Integer>();
private long startTime,startTime2 = 0;
private long endTime,endTime2 = 0;
private long costTime,totalCostTime = 0;
/*
* @param times
* 求平均的次数
* @param num
* 向list中操作的次数
* */
private void testArrayInsert(int times, int num) {
long totalCostTime = 0;
long costTime = 0;
long startTime = 0;
long endTime = 0;
for(int j=0; j<times; j++) {
alist = null;
alist = new ArrayList<Integer>();
costTime = 0;
startTime = 0;
endTime = 0;
startTime = System.currentTimeMillis();
for (int i = 0; i < num; i++) {
alist.add(i);
}
endTime = System.currentTimeMillis();
costTime = endTime - startTime;
totalCostTime += costTime;
}
System.out.println("insert into arraylist for "+times+" times cost:" + totalCostTime/times);
}
private void testLinkedInsert(int times, int num){
long totalCostTime = 0;
long costTime = 0;
long startTime = 0;
long endTime = 0;
for(int j=0; j<times; j++) {
llist = null;
llist = new LinkedList<Integer>();
costTime = 0;
startTime = 0;
endTime = 0;
startTime = System.currentTimeMillis();
for (int i = 0; i < num; i++) {
llist.add(i);
}
endTime = System.currentTimeMillis();
costTime = endTime - startTime;
totalCostTime += costTime;
}
System.out.println("insert into linkedlist for "+times+" times cost:" + totalCostTime/times);
}
private void testArrayInsertLast(int times, int num) {
long totalCostTime = 0;
long costTime = 0;
long startTime = 0;
long endTime = 0;
for(int j=0; j<times; j++) {
alist = null;
alist = new ArrayList<Integer>();
costTime = 0;
startTime = 0;
endTime = 0;
startTime = System.currentTimeMillis();
for (int i = 0; i < num; i++) {
alist.add(i);
}
endTime = System.currentTimeMillis();
costTime = endTime - startTime;
totalCostTime += costTime;
}
System.out.println("insert into the last of arraylist for "+times+" times cost:" + totalCostTime/times);
}
private void testLinkedInsertLast(int times, int num){
long totalCostTime = 0;
long costTime = 0;
long startTime = 0;
long endTime = 0;
for(int j=0; j<times; j++) {
llist = null;
llist = new LinkedList<Integer>();
costTime = 0;
startTime = 0;
endTime = 0;
startTime = System.currentTimeMillis();
for (int i = 0; i < num; i++) {
llist.addLast(i);
}
endTime = System.currentTimeMillis();
costTime = endTime - startTime;
totalCostTime += costTime;
}
System.out.println("insert into the last of linkedlist for "+times+" times cost:" + totalCostTime/times);
}
private void testArrayFind(int times, int num) {
long totalCostTime = 0;
long costTime = 0;
long startTime = 0;
long endTime = 0;
for(int j=0; j<times; j++) {
alist = null;
alist = new ArrayList<Integer>();
costTime = 0;
startTime = 0;
endTime = 0;
for (int i = 0; i < num; i++) {
alist.add(i);
}
startTime = System.currentTimeMillis();
for (int i = 0; i < num; i++) {
alist.get(i);
}
endTime = System.currentTimeMillis();
costTime = endTime - startTime;
totalCostTime += costTime;
}
System.out.println("find from arraylist for "+times+" times cost:" + totalCostTime/times);
}
private void testLinkedFind(int times, int num){
long totalCostTime = 0;
long costTime = 0;
long startTime = 0;
long endTime = 0;
for(int j=0; j<times; j++) {
llist = null;
llist = new LinkedList<Integer>();
costTime = 0;
startTime = 0;
endTime = 0;
for (int i = 0; i < num; i++) {
llist.add(i);
}
startTime = System.currentTimeMillis();
for (int i = 0; i < num; i++) {
llist.get(i);
}
endTime = System.currentTimeMillis();
costTime = endTime - startTime;
totalCostTime += costTime;
}
System.out.println("find from linkedlist for "+times+" times cost:" + totalCostTime/times);
}
/*
* @param times
* 求平均的次数
* @param num
* 向list中操作的次数
* @param num_remove
* 删除的次数
* */
private void testArrayRemove(int times, int num, int num_remove) {
long totalCostTime = 0;
long costTime = 0;
long startTime = 0;
long endTime = 0;
for(int j=0; j<times; j++) {
alist = null;
alist = new ArrayList<Integer>();
costTime = 0;
startTime = 0;
endTime = 0;
for (int i = 0; i < num; i++) {
alist.add(i);
}
startTime = System.currentTimeMillis();
for (int i = 0; i < num_remove; i++) {
alist.remove(i);
}
endTime = System.currentTimeMillis();
costTime = endTime - startTime;
totalCostTime += costTime;
}
System.out.println("remove "+num_remove+" numbers from arraylist for "+times+" times cost:" + totalCostTime/times);
}
private void testLinkedRemove(int times, int num, int num_remove){
long totalCostTime = 0;
long costTime = 0;
long startTime = 0;
long endTime = 0;
for(int j=0; j<times; j++) {
llist = null;
llist = new LinkedList<Integer>();
costTime = 0;
startTime = 0;
endTime = 0;
for (int i = 0; i < num; i++) {
llist.add(i);
}
startTime = System.currentTimeMillis();
for (int i = 0; i < num_remove; i++) {
llist.remove(i);
}
endTime = System.currentTimeMillis();
costTime = endTime - startTime;
totalCostTime += costTime;
}
System.out.println("remove " + num_remove + " numbers from linkedlist for "+times+" times cost:" + totalCostTime/times);
}
public static void main(String args[]){
Vs vs = new Vs();
//由于不同操作时间长度不同，为了减少等待时间，为同一个参数设置了大小。
int times_small = 1; //重复次数-小
int times_large = 10;//重复次数-大
int num_small = 100000;//操作次数-小
int num_large = 1000000;//操作次数-大
//插入操作时间较短，因此设置的都是大的参数，比较有代表性
vs.testArrayInsert(times_large,num_large);
vs.testLinkedInsert(times_large,num_large);
vs.testArrayInsertLast(times_large, num_large);
vs.testLinkedInsertLast(times_large, num_large);
//linkedlist删除操作花太久时间，因此传入了小的参数，不影响比较
vs.testArrayFind(times_small, num_small);
vs.testLinkedFind(times_small, num_small);
//删除操作直接设置为1000次删除
vs.testArrayRemove(times_small, num_small, 1000);
vs.testLinkedRemove(times_small, num_small, 1000);
}
}
时间： 2024-11-10 08:43:06