LinkedList

package com.apitest;

import java.util.ArrayList;
import java.util.Date;
import java.util.LinkedList;
import java.util.List;
import java.util.stream.Collectors;

public class LinkedListStreamDemo {
    public static void main(String[] args) {
        int size = 1 << 16;


        LinkedList<Integer> linkedList = new LinkedList<>();
        for (int i = 0; i < size; i++) {
            linkedList.add(i);
        }

        /**
         * 102毫秒
         */
        long before2 = new Date().getTime();
        List<Integer> list2 = linkedList.parallelStream().filter(i -> i % 2 != 0).collect(Collectors.toList());
        long after2 = new Date().getTime();
        System.out.println(after2-before2);
        for (int i: list2) {
            System.out.printf("%d,", i);
        }
        System.out.println();


        /**
         * 122毫秒
         */
//        long before = new Date().getTime();
//        List<Integer> list = linkedList.stream().filter(i -> i % 2 == 0).collect(Collectors.toList());
//        long after = new Date().getTime();
//        System.out.println(after-before);
//        for (int i: list) {
//            System.out.printf("%d,", i);
//        }
//        System.out.println();
//
        /**
         * 1216毫秒
         */
//        long before1 = new Date().getTime();
//        LinkedList<Integer> list1 = new LinkedList<>();
//        for (int i:linkedList) {
//            if(i % 2 == 0){
//                list1.add(linkedList.get(i));
//            }
//        }
//        long after1 = new Date().getTime();
//        System.out.println(after1-before1);
//        for (int i: list1) {
//            System.out.printf("%d,", i);
//        }
//        System.out.println();

    }
}

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ArrayList

package com.apitest;

import java.util.ArrayList;
import java.util.Date;
import java.util.LinkedList;
import java.util.List;
import java.util.stream.Collectors;

public class ArrayListStreamDemo {
    public static void main(String[] args) {
        int size = 1 << 18;


        ArrayList<Integer> arrayList = new ArrayList<>();
        for (int i = 0; i < size; i++) {
            arrayList.add(i);
        }
        /**
         * 122毫秒
         */
        long before = new Date().getTime();
        List<Integer> list = arrayList.stream().filter(i -> i % 2 == 0).collect(Collectors.toList());
        long after = new Date().getTime();
        /**
         * 20毫秒
         */
        long before2 = new Date().getTime();
        List<Integer> list2 = arrayList.parallelStream().filter(i -> i % 2 != 0).collect(Collectors.toList());
        long after2 = new Date().getTime();




        /**
         * 18毫秒
         */
        long before1 = new Date().getTime();
        LinkedList<Integer> list1 = new LinkedList<>();
        for ( int i = 0; i < arrayList.size(); i++) {
            if(arrayList.get(i) % 2 == 0){
                list1.add(arrayList.get(i));
            }
        }
        long after1 = new Date().getTime();
        System.out.println();

        for (int i = 0; i < list.size(); i++) {
            System.out.printf("%d,", list.get(i));
        }
        System.out.println();

        for (int i = 0; i < list1.size(); i++) {
            System.out.printf("%d,", list1.get(i));
        }
        System.out.println();

        for (int i = 0; i < list2.size(); i++) {
            System.out.printf("%d,", list2.get(i));
        }
        System.out.println();
        System.out.println(after-before);
        System.out.println(after2-before2);
        System.out.println(after1-before1);

    }
}

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HashMap

package com.apitest;

import java.util.*;
import java.util.stream.Collectors;

public class HashMapStreamDemo {

    public static void main(String[] args) {
        int size = 1 << 16;
        HashMap<Integer, Integer> hashMap = new HashMap<>();
        for (int i = 0; i < size; i++) {
            hashMap.put(i, i);
        }

        /**
         * 46624毫秒
         */
        long before = new Date().getTime();
        Set<Map.Entry<Integer, Integer>> entrySet = hashMap.entrySet().stream().filter(entry -> entry.getKey() % 2 == 0).collect(Collectors.toSet());
        long after = new Date().getTime();
        System.out.println(after-before);

        /**
         * 44545毫秒
         */
        long before1 = new Date().getTime();
        Set<Map.Entry<Integer, Integer>> entrySet1 = new HashSet<>();
        for (Map.Entry<Integer, Integer> entry: hashMap.entrySet()) {
            if (entry.getKey() % 2 == 0) {
                entrySet1.add(entry);
            }
        }
        long after1 = new Date().getTime();
        System.out.println(after1-before1);

        System.out.println(entrySet);
        System.out.println(entrySet1);
    }

}

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TreeMap

package com.apitest;

import java.util.*;
import java.util.stream.Collectors;

public class TreeMapStreamDemo {
    public static void main(String[] args) {

        int size = 1 << 16;
        TreeMap<Integer, Integer> treeMap = new TreeMap<>();
        for (int i = 0; i < size; i++) {
            treeMap.put(i, i);
        }

        /**
         * 48112毫秒
         */
        long before = new Date().getTime();
        Set<Map.Entry<Integer, Integer>> entrySet = treeMap.entrySet().stream().filter(entry -> entry.getKey() % 2 == 0).collect(Collectors.toSet());
        long after = new Date().getTime();
        System.out.println(after-before);

        /**
         * 48210毫秒
         */
        long before1 = new Date().getTime();
        Set<Map.Entry<Integer, Integer>> entrySet1 = new HashSet<>();
        for (Map.Entry<Integer, Integer> entry: treeMap.entrySet()) {
            if (entry.getKey() % 2 == 0) {
                entrySet1.add(entry);
            }
        }
        long after1 = new Date().getTime();
        System.out.println(after1-before1);

        System.out.println(entrySet);
        System.out.println(entrySet1);
    }
}

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HashSet

package com.apitest;

import java.util.Date;
import java.util.HashSet;
import java.util.Set;
import java.util.TreeSet;
import java.util.stream.Collectors;

public class HashSetStreamDemo {
    public static void main(String[] args) {
        int size = 1 << 20;
        HashSet<Integer> hashSet = new HashSet<>();
        for (int i = 0; i < size; i++) {
            hashSet.add(i);
        }

        /**
         * 1114毫秒
         */
        long before = new Date().getTime();
        Set<Integer> entrySet = hashSet.stream().filter(i->(i % 2 == 0)).collect(Collectors.toSet());
        long after = new Date().getTime();
        System.out.println(after-before);

        /**
         * 60毫秒
         */
        long before1 = new Date().getTime();
        Set<Integer> set = new HashSet<>();
        for (Integer integer: hashSet) {
            if (integer % 2 == 0) {
                set.add(integer);
            }
        }
        long after1 = new Date().getTime();
        System.out.println(after1-before1);

        System.out.println(entrySet.size());
        System.out.println(set.size());

    }
}

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TreeSet

package com.apitest;

import java.util.*;
import java.util.stream.Collectors;

public class TreeSetStreamDemo {
    public static void main(String[] args) {

        int size = 1 << 20;
        TreeSet<Integer> treeSet = new TreeSet<>();
        for (int i = 0; i < size; i++) {
            treeSet.add(i);
        }

        /**
         * 863毫秒
         */
        long before = new Date().getTime();
        Set<Integer> entrySet = treeSet.stream().filter(i->(i % 2 == 0)).collect(Collectors.toSet());
        long after = new Date().getTime();
        System.out.println(after-before);

        /**
         * 56毫秒
         */
        long before1 = new Date().getTime();
        Set<Integer> entrySet1 = new HashSet<>();
        for (Integer integer: treeSet) {
            if (integer % 2 == 0) {
                entrySet1.add(integer);
            }
        }
        long after1 = new Date().getTime();
        System.out.println(after1-before1);

        System.out.println(entrySet.size());
        System.out.println(entrySet1.size());
    }
}

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