Java中List和Map的特性对两组大批量数据进行匹配

/**
 * For循环测试
 * @author 大漠
 *
 */
public class ForTest {
 public static void main(String[] args) {
  ForTest test = new ForTest();
  System.out.println("============开始=============");
   //一亿次for循环
   test.test1Yi();
   //十一万次for循环
   test.test11W();
   //嵌套for循环匹配：10W*1W次for循环
   test.testForAndFor();
   //Map和List整理匹配：10W+1W次for循环
   test.testMapAndList();
  System.out.println("============结束=============");
 }
 /**
  * 一亿次for循环
  */
 private void test1Yi(){
  long start = System.currentTimeMillis();
  for (Integer i = 0; i < 100000000;i++) {
   System.out.println(i);
  }
  long end = System.currentTimeMillis();
  System.out.println("1亿次循环耗时："+ (end - start) + "毫秒");
  System.out.println("----------------------------");
 }
 
 /**
  * 11万次for循环
  */
 private void test11W(){
  long start = System.currentTimeMillis();
  for (Integer i = 0; i < 110000;i++) {
   System.out.println(i);
  }
  long end = System.currentTimeMillis();
  System.out.println("11W次循环耗时："+ (end - start) + "毫秒");
  System.out.println("----------------------------");
 }
 
 /**
  * 嵌套for循环进行比较匹配
  */
 private void  testForAndFor(){
  //构造一个10万个Person对象的list
  List<Person> personList = new ArrayList<Person>();
  for (int i = 0; i < 100000; i++) {
   int j =10000;
   personList.add(new Person((i%j) +"", "张三"+i));
  }
  //构造一个1万个String对象的list
  List<String> strList = new ArrayList<String>();
  for (int i = 0; i < 10000; i++) {
   strList.add(i +"");
  }
  
  //嵌套for循环：10W*1W
  long start = System.currentTimeMillis();
  //保存匹配结果
        List<Person> resultList = new ArrayList<Person>();
        //遍历10W person的List
        for (Person person : personList) {
         //遍历1W str的List
            for (String str : strList) {
                if(person.getId().equals(str)){
                    resultList.add(person);
                }
            }
        }
        long end = System.currentTimeMillis(); 
        System.out.println("reslutList.size:"+ resultList.size());
        System.out.println("10W*1W次循环耗时："+ (end - start) + "毫秒");
        System.out.println("----------------------------");
 }
 
 /**
  * 使用Map和List的特性进行匹配:
  * Map为key-value结构，不能放重复数据
  * List可以放重复数据
  * 使用String型id做key,List<Person>做value
  * 遍历List<String>, map.get(String)则取出id == str 的List
  */
 private void  testMapAndList(){
  //构造一个10万个Person对象的list
  List<Person> personList = new ArrayList<Person>();
  
  for (int i = 0; i < 100000; i++) {
   int j =10000;
   personList.add(new Person((i%j) +"", "张三"+i));
  }
  //构造一个1万个String对象的list
  List<String> strList = new ArrayList<String>();
  for (int i = 0; i < 10000; i++) {
   strList.add(i +"");
  }
  
  long start = System.currentTimeMillis();
  //利用Map和List的特性整理数据
        Map<String, List<Person>> map = new HashMap<String, List<Person>>();
        //将10W条数据根据id放入map
        for(int i=0;i<personList.size();i++){
         Person person = personList.get(i);
             String id = person.getId();
              if(map.containsKey(id)){
                  map.get(id).add(person);
              }else{
                   List<Person> pList = new ArrayList<Person>();
                   pList.add(person);
                   //id为key,相同id的person的List为value
                   map.put(id,pList);
             }
        }
      //保存匹配结果
        List<Person> resultList = new ArrayList<Person>();
        //根据1W条str,map.get(str)取匹配上的数据
        for (String str : strList) {
            List<Person> pList = map.get(str);
            if (pList != null) {
                resultList.addAll(pList);
            }
        }
        long end = System.currentTimeMillis();
        System.out.println("map.size:" +map.size());
        System.out.println("reslutList.size:"+ resultList.size());
        System.out.println("10W+1W次循环耗时："+ (end - start) + "毫秒");
  System.out.println("----------------------------");
 }

}

/**
 * Person实体类
 */
class Person{
 private String id;
 private String name;

 public Person() {}
 
 public Person(String id, String name) {
  this.id = id;
  this.name = name;
 }

 @Override
 public String toString() {
  return this.id +"::>"+ this.name;
 }
 
 public String getId() {
  return id;
 }
 public void setId(String id) {
  this.id = id;
 }
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }
}