java如何按升序排列输出？

Question

因此，我编写了代码，从文件中读取数据并进行一些计算，然后生成如下输出：

First Name = tony
Last Name = wroten
Geometric Mean = 663002.7727000846
----------------------------

First Name = nick
Last Name = young
Geometric Mean 128740.18176156192

但它只是一个输出，不存储在任何地方。有没有办法根据几何平均数按升序排列输出

Answer 1

• 为您的文件信息创建一个持有者。例如PersonVO，根据我下面的代码
• 您读取文件并为此人设置值的逻辑可能会更改。我刚才举了一个例子
• 完成后，将每个人添加到列表中
• 然后对列表进行排序

• 由于排序是基于特定属性的，因此我们必须创建一个自定义比较器，它是PersonComparator，如下面的示例所示

  public static void main(String[] args) {
  
  
              PersonVO person1 = new PersonVO("firstname1", "lastname1", 2.1);
              PersonVO person2 = new PersonVO("firstname2", "lastname2", 1.1);
  
              List<PersonVO> personList = new ArrayList<PersonVO>();
              personList.add(person1);
              personList.add(person2);
  
              System.out.println("Before Sort");
              System.out.println(personList);
  
              Collections.sort(personList, new PersonComparator());
              System.out.println("After Sort");
              System.out.println(personList);
          }
  

这是VO的一个示例实现，它保存从文件读取到类的每个人的信息

public class PersonVO {


    public PersonVO(String firstName, String lastName, double mean) {
        super();
        this.firstName = firstName;
        this.lastName = lastName;
        this.mean = mean;
    }
    private String firstName;
    private String lastName;
    private double mean;


    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public double getMean() {
        return mean;
    }
    public void setMean(double mean) {
        this.mean = mean;
    }
    @Override
    public String toString() {
        return "PersonVO [firstName=" + firstName + ", lastName=" + lastName
                + ", mean=" + mean + "]";
    }


}

下面是比较器的实现

import java.util.Comparator;


    public class PersonComparator implements Comparator<PersonVO> {

        @Override
        public int compare(PersonVO p1, PersonVO p2) {
            return Double.valueOf(p1.getMean()).compareTo(Double.valueOf(p2.getMean()));
        }

    }