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新增List测试示例

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xuwujing
2019-02-21 18:00:06 +08:00
parent 447941155b
commit bb97b1c821
1 changed files with 295 additions and 292 deletions
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src/main/java/com/pancm/basics/ListTest.java
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package com.pancm.basics;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Vector;
import java.util.stream.Collectors;
/**
*
* @Title: ListTest
* @Description:关于list测试
* @Version:1.0.0
* @author pancm
* @date 2017年10月13日
*/
public class ListTest {
private final static int count=50000;
private static ArrayList arrayList = new ArrayList<>();
private static LinkedList linkedList = new LinkedList<>();
private static Vector vector = new Vector<>();
public static void main(String[] args) {
// test1();
// test2();
// test3();
test4();
// test5();
Vector<String> v=new Vector<>();
}
/**
* 遍历方法
*/
private static void test1() {
List<String> list=new ArrayList<String>();
list.add("a");
list.add("b");
list.add("c");
System.out.println("list截取:"+list.subList(0, 1));
System.out.println("list截取:"+list.subList(1, 3));
//第一种使用
for(int i=0;i<list.size();i++){
System.out.println(list.get(i));
}
//第二种遍历方法使用foreach遍历List
for (String str : list) {
System.out.println(str);
}
//第三种遍历 使用迭代器进行相关遍历
Iterator<String> iterator=list.iterator();
while(iterator.hasNext())//判断下一个元素之后有值
{
System.out.println(iterator.next());
}
}
/**
* 数组变化遍历
*/
private static void test2() {
List<String> list1 = new ArrayList<String>();
list1.add("1");
list1.add("2");
System.out.println("list1遍历之前:"+list1);
Iterator<String> iterator = list1.iterator();
while (iterator.hasNext()) {
String item = iterator.next();
if ("2".equals(item)) {
iterator.remove();
}
}
System.out.println("list1遍历之后:"+list1);
List<String> list = new ArrayList<String>();
list.add("1");
list.add("2");
System.out.println("list遍历之前:"+list);
for (String item : list) {
if ("2".equals(item)) {
list.remove(item);
//如果这里不适用break的话，会直接报错的
break;
}
}
System.out.println("list遍历之后:"+list);
}
/**
* 常用方法
*/
private static void test3() {
List<Integer> list=initData(100);
System.out.println("list:"+list);
System.out.println("removeList:"+removeList(list,10,20));
list.subList(10, 20).clear();
System.out.println("subList:"+list);
List<String> ls1=new ArrayList<String>();
List<String> ls2=new ArrayList<String>();
ls1.add("a");
ls1.add("b");
ls1.add("c");
ls2.add("a");
ls2.add("d");
ls2.add("e");
// System.out.println("合集:"+addAll(ls1,ls2));
System.out.println("交集 :"+retainAll(ls1,ls2));
System.out.println("差集 :"+removeAll(ls1,ls2));
System.out.println("并集 :"+andAll(ls1,ls2));
}
private static void test4() {
LinkedList<Integer> list=new LinkedList<Integer>();
list.add(3);
list.add(5);
list.add(4);
System.out.println(list);
list.addFirst(2);
list.addLast(4);
System.out.println(list);
LinkedList<Integer> list2=new LinkedList<Integer>();
list2.add(1);
list2.add(2);
list2.add(4);
list2.add(4);
list2.add(6);
list2.add(6);
list2.add(5);
System.out.println("去重之前:"+list2);
//jdk1.8去重
List<Integer> newList = list2.stream().distinct().collect(Collectors.toList());
System.out.println("去重之后:"+newList);
}
private static void test5() {
insertList(arrayList);
insertList(linkedList);
insertList(vector);
System.out.println("--------------------");
readList(arrayList);
readList(linkedList);
readList(vector);
System.out.println("--------------------");
delList(arrayList);
delList(linkedList);
delList(vector);
}
private static void insertList(List list){
long start=System.currentTimeMillis();
Object o = new Object();
for(int i=0;i<count;i++){
list.add(0, o);
}
System.out.println(getName(list)+"插入"+count+"条数据，耗时:"+(System.currentTimeMillis()-start)+"ms");
}
private static void readList(List list){
long start=System.currentTimeMillis();
Object o = new Object();
for(int i = 0 ; i < count ; i++){
list.get(i);
}
System.out.println(getName(list)+"查询"+count+"条数据，耗时:"+(System.currentTimeMillis()-start)+"ms");
}
private static void delList(List list){
long start=System.currentTimeMillis();
Object o = new Object();
for(int i = 0 ; i < count ; i++){
list.remove(0);
}
System.out.println(getName(list)+"删除"+count+"条数据，耗时:"+(System.currentTimeMillis()-start)+"ms");
}
private static String getName(List list) {
String name = "";
if(list instanceof ArrayList){
name = "ArrayList";
}
else if(list instanceof LinkedList){
name = "LinkedList";
}
else if(list instanceof Vector){
name = "Vector";
}
return name;
}
/**
* for循环移除指定数据
* @param list
* @param s 要移除的起始位置
* @param d 要移除的最后位置
*/
private static List<Integer> removeList(List<Integer> list,int s,int d){
for(int i=0,j=list.size();i<j;i++){
if(i>=s&&i<d){
list.remove(i);
}
}
return list;
}
/**
* 获取数组数据
* @param j
* @return
*/
private static List<Integer> initData(int j){
List<Integer> list=new ArrayList<Integer>();
for(int i=1;i<=j;i++){
list.add(i);
}
return list;
}
/**
* 数组合集
* @param ls1
* @param ls2
* @return
*/
private static List<String> addAll(List<String> ls1,List<String>ls2){
ls1.addAll(ls2);
return ls1;
}
/**
* 数组交集 （retainAll 会删除 ls1在ls2中没有的元素）
* @param ls1
* @param ls2
* @return
*/
private static List<String> retainAll(List<String> ls1,List<String>ls2){
System.out.println("ls1:"+ls1+";ls2:"+ls2);
ls1.retainAll(ls2);
return ls1;
}
/**
* 差集 (删除ls2中没有ls1中的元素)
* @param ls1
* @param ls2
* @return
*/
private static List<String> removeAll(List<String> ls1,List<String>ls2){
ls1.removeAll(ls2);
System.out.println(ls1+";ls2:"+ls2);
return ls1;
}
/**
* 无重复的并集 (ls1和ls2中并集，并无重复)
* @param ls1
* @param ls2
* @return
*/
private static List<String> andAll(List<String> ls1,List<String>ls2){
//删除在ls1中出现的元素
ls2.removeAll(ls1);
//将剩余的ls2中的元素添加到ls1中
ls1.addAll(ls2);
System.out.println(ls1+";ls2:"+ls2);
return ls1;
}
}
package com.pancm.basics;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Vector;
import java.util.stream.Collectors;
/**
*
* @Title: ListTest
* @Description:关于list测试
* @Version:1.0.0
* @author pancm
* @date 2017年10月13日
*/
public class ListTest {
private final static int count=50000;
private static ArrayList arrayList = new ArrayList<>();
private static LinkedList linkedList = new LinkedList<>();
private static Vector vector = new Vector<>();
public static void main(String[] args) {
// test1();
// test2();
test3();
// test4();
// test5();
Vector<String> v=new Vector<>();
}
/**
* 遍历方法
*/
private static void test1() {
List<String> list=new ArrayList<String>();
list.add("a");
list.add("b");
list.add("c");
System.out.println("list截取:"+list.subList(0, 1));
System.out.println("list截取:"+list.subList(1, 3));
//第一种使用
for(int i=0;i<list.size();i++){
System.out.println(list.get(i));
}
//第二种遍历方法使用foreach遍历List
for (String str : list) {
System.out.println(str);
}
//第三种遍历 使用迭代器进行相关遍历
Iterator<String> iterator=list.iterator();
while(iterator.hasNext())//判断下一个元素之后有值
{
System.out.println(iterator.next());
}
}
/**
* 数组变化遍历
*/
private static void test2() {
List<String> list1 = new ArrayList<String>();
list1.add("1");
list1.add("2");
System.out.println("list1遍历之前:"+list1);
Iterator<String> iterator = list1.iterator();
while (iterator.hasNext()) {
String item = iterator.next();
if ("2".equals(item)) {
iterator.remove();
}
}
System.out.println("list1遍历之后:"+list1);
List<String> list = new ArrayList<String>();
list.add("1");
list.add("2");
System.out.println("list遍历之前:"+list);
for (String item : list) {
if ("2".equals(item)) {
list.remove(item);
//如果这里不适用break的话，会直接报错的
break;
}
}
System.out.println("list遍历之后:"+list);
}
/**
* 常用方法
*/
private static void test3() {
List<Integer> list=initData(100);
System.out.println("list:"+list);
System.out.println("removeList:"+removeList(list,10,20));
list.subList(10, 20).clear();
System.out.println("subList:"+list);
List<String> ls1=new ArrayList<String>();
List<String> ls2=new ArrayList<String>();
ls1.add("a");
ls1.add("b");
ls1.add("c");
ls2.add("a");
ls2.add("b");
ls2.add("c");
ls2.add("e");
// System.out.println("合集:"+addAll(ls1,ls2));
// System.out.println("交集 :"+retainAll(ls1,ls2));
System.out.println("差集 :"+removeAll(ls2,ls1));
// System.out.println("并集 :"+andAll(ls1,ls2));
}
private static void test4() {
LinkedList<Integer> list=new LinkedList<Integer>();
list.add(3);
list.add(5);
list.add(4);
System.out.println(list);
list.addFirst(2);
list.addLast(4);
System.out.println(list);
LinkedList<Integer> list2=new LinkedList<Integer>();
list2.add(1);
list2.add(2);
list2.add(4);
list2.add(4);
list2.add(6);
list2.add(6);
list2.add(5);
System.out.println("去重之前:"+list2);
//jdk1.8去重
List<Integer> newList = list2.stream().distinct().collect(Collectors.toList());
System.out.println("去重之后:"+newList);
}
private static void test5() {
insertList(arrayList);
insertList(linkedList);
insertList(vector);
System.out.println("--------------------");
readList(arrayList);
readList(linkedList);
readList(vector);
System.out.println("--------------------");
delList(arrayList);
delList(linkedList);
delList(vector);
}
private static void insertList(List list){
long start=System.currentTimeMillis();
Object o = new Object();
for(int i=0;i<count;i++){
list.add(0, o);
}
System.out.println(getName(list)+"插入"+count+"条数据，耗时:"+(System.currentTimeMillis()-start)+"ms");
}
private static void readList(List list){
long start=System.currentTimeMillis();
Object o = new Object();
for(int i = 0 ; i < count ; i++){
list.get(i);
}
System.out.println(getName(list)+"查询"+count+"条数据，耗时:"+(System.currentTimeMillis()-start)+"ms");
}
private static void delList(List list){
long start=System.currentTimeMillis();
Object o = new Object();
for(int i = 0 ; i < count ; i++){
list.remove(0);
}
System.out.println(getName(list)+"删除"+count+"条数据，耗时:"+(System.currentTimeMillis()-start)+"ms");
}
private static String getName(List list) {
String name = "";
if(list instanceof ArrayList){
name = "ArrayList";
}
else if(list instanceof LinkedList){
name = "LinkedList";
}
else if(list instanceof Vector){
name = "Vector";
}
return name;
}
/**
* for循环移除指定数据
* @param list
* @param s 要移除的起始位置
* @param d 要移除的最后位置
*/
private static List<Integer> removeList(List<Integer> list,int s,int d){
for(int i=0,j=list.size();i<j;i++){
if(i>=s&&i<d){
list.remove(i);
}
}
return list;
}
/**
* 获取数组数据
* @param j
* @return
*/
private static List<Integer> initData(int j){
List<Integer> list=new ArrayList<Integer>();
for(int i=1;i<=j;i++){
list.add(i);
}
return list;
}
/**
* 数组合集
* @param ls1
* @param ls2
* @return
*/
private static List<String> addAll(List<String> ls1,List<String>ls2){
ls1.addAll(ls2);
return ls1;
}
/**
* 数组交集 （retainAll 会删除 ls1在ls2中没有的元素）
* @param ls1
* @param ls2
* @return
*/
private static List<String> retainAll(List<String> ls1,List<String>ls2){
System.out.println("ls1:"+ls1+";ls2:"+ls2);
ls1.retainAll(ls2);
return ls1;
}
/**
* 差集 (删除ls2中没有ls1中的元素)
* @param ls1
* @param ls2
* @return
*/
private static List<String> removeAll(List<String> ls1,List<String>ls2){
System.out.println("ls1:"+ls1+";ls2:"+ls2);
ls1.removeAll(ls2);
return ls1;
}
/**
* 无重复的并集 (ls1和ls2中并集，并无重复)
* @param ls1
* @param ls2
* @return
*/
private static List<String> andAll(List<String> ls1,List<String>ls2){
//删除在ls1中出现的元素
ls2.removeAll(ls1);
//将剩余的ls2中的元素添加到ls1中
ls1.addAll(ls2);
System.out.println(ls1+";ls2:"+ls2);
return ls1;
}
}