Java优化for循环嵌套的高效率方法

for(Member m2:list2){
 if(m2.getName()==null){
 for(Member m1:list1){
  if(m1.getId().intValue()==m2.getId().intValue()){
  System.out.println(m2.getId()+" Name 值为空!!!");
  }
 }
 }
}

import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;
 
class Member {
 private Integer id;
 private String name;
 private Integer age;
 private Date addDate;
 
 public Member() {
 }
 
 public Member(Integer id, String name, Integer age, Date addDate) {
 super();
 this.id = id;
 this.name = name;
 this.age = age;
 this.addDate = addDate;
 }
 
 public Integer getId() {
 return id;
 }
 
 public void setId(Integer id) {
 this.id = id;
 }
 
 public String getName() {
 return name;
 }
 
 public void setName(String name) {
 this.name = name;
 }
 
 public Integer getAge() {
 return age;
 }
 
 public void setAge(Integer age) {
 this.age = age;
 }
 
 public Date getAddDate() {
 return addDate;
 }
 
 public void setAddDate(Date addDate) {
 this.addDate = addDate;
 }
 
}
 
public class For2 {
 
 public static void main(String[] args) throws InterruptedException {
 List<Member> list1 = new ArrayList<>();
 List<Member> list2 = new ArrayList<>();
 for(int i=0;i<30000;i++){
  Date date = new Date();
  list1.add(new Member((i+1),"技术客",(i+1), date));
  if(i%2==0){
  list2.add(new Member((i+1),null,(i+1), date));
  }
 }
  
 //双for循环嵌套测试
 long s1 = System.currentTimeMillis();
 int forNumber = 0;
 for(Member m2:list2){
  if(m2.getName()==null){
  for(Member m1:list1){
   if(m1.getId().intValue()==m2.getId().intValue()){
//   System.out.println(m2.getId()+" Name 值为空!!!");
   forNumber++;
   }
  }
  }
 }
 long s2 = System.currentTimeMillis();
 System.out.println("双for循环查询时间为："+(s2-s1)+"(毫秒)，一共查询出"+forNumber+"条数据 \n\n\n");
 TimeUnit.SECONDS.sleep(3);
  
 //map查询测试
 long s3 = System.currentTimeMillis();
  
 int mapNumber = 0;
 Map<Integer, Member> map = new HashMap<>();
 for(Member m1:list1){
  map.put(m1.getId(), m1);
 }
 for(Member m2:list2){
  if(m2.getName()==null){
  Member m = map.get(m2.getId());
  if(m!=null){
//   System.out.println(m2.getId()+" Name 值为空!!!");
   mapNumber++;
  }
  }
 }
 long s4 = System.currentTimeMillis();
 System.out.println("使用map结构查询时间为："+(s4-s3)+"(毫秒)，一共查询出"+mapNumber+"条数据 \n\n\n");
 }
 
}