您可以实现一个Comparator来比较两个Person对象，并且可以检查任意数量的字段。你可以在比较器中放入一个变量，告诉它与哪个字段进行比较，尽管只编写多个比较器可能会更简单。

我认为如果你的比较算法是“聪明的”，那就更令人困惑了。我会选择你建议的众多比较方法。

对我来说唯一的例外就是平等。对于单元测试，重写. equals(在.net中)对我来说很有用，以便确定两个对象之间的几个字段是否相等(而不是引用是否相等)。

如果我们必须基于多个字段对Person对象进行排序，则相同的代码实现在这里。

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class Person {

private String firstName;
private String lastName;
private int age;

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 int getAge() {
    return age;
}

public void setAge(int age) {
    this.age = age;
}

public Person(String firstName, String lastName, int age) {
    this.firstName = firstName;
    this.lastName = lastName;
    this.age = age;
}


static class PersonSortingComparator implements Comparator<Person> {

    @Override
    public int compare(Person person1, Person person2) {

        // for first name comparison
        int firstNameCompare = person1.getFirstName().compareTo(person2.getFirstName());

        // for last name comparison
        int lastNameCompare = person1.getLastName().compareTo(person2.getLastName());

        // for last name comparison
        int ageCompare = person1.getAge() - person2.getAge();

        // Now comparing
        if (firstNameCompare == 0) {
            if (lastNameCompare == 0) {
                return ageCompare;
            }
            return lastNameCompare;
        }
        return firstNameCompare;
    }
}

public static void main(String[] args) {
    Person person1 = new Person("Ajay", "Kumar", 27);
    Person person2 = new Person("Ajay","Gupta", 23);
    Person person3 = new Person("Ajay","Kumar", 22);


    ArrayList<Person> persons = new ArrayList<>();
    persons.add(person1);
    persons.add(person2);
    persons.add(person3);


    System.out.println("Before Sorting:\n");
    for (Person person : persons) {
        System.out.println(person.firstName + " " + person.lastName + " " + person.age);
    }

    Collections.sort(persons, new PersonSortingComparator());

    System.out.println("After Sorting:\n");
    for (Person person : persons) {
        System.out.println(person.firstName + " " + person.lastName + " " + person.age);
    }
}

}

晚做总比不到好——如果你正在寻找不必要的混乱或开销，那么很难同时在最少的代码/快速执行方面击败下面的方法。

数据类:

public class MyData {
    int id;
    boolean relevant;
    String name;
    float value;
}

比较器:

public class MultiFieldComparator implements Comparator<MyData> {
    @Override
    public int compare(MyData dataA, MyData dataB) {
        int result;
        if((result = Integer.compare(dataA.id, dataB.id)) == 0 &&
           (result = Boolean.compare(dataA.relevant, dataB.relevant)) == 0 &&
           (result = dataA.name.compareTo(dataB.name)) == 0)
            result = Float.compare(dataA.value, dataB.value);
        return result;
    }
}

如果你只是想按自定义顺序对集合进行排序，那么下面的代码就更清晰了:

myDataList.sort((dataA, dataB) -> {
    int result;
    if((result = Integer.compare(dataA.id, dataB.id)) == 0 &&
       (result = Boolean.compare(dataA.relevant, dataB.relevant)) == 0 &&
       (result = dataA.name.compareTo(dataB.name)) == 0)
        result = Float.compare(dataA.value, dataB.value);
    return result;
});

与比较方法不同，您可能只想在Person类中定义几种类型的“Comparator”子类。这样就可以将它们传递到标准的Collections排序方法中。

您应该实现Comparable <Person>。假设所有字段都不为空(为了简单起见)，年龄是int型，比较排名是第一，最后，年龄，compareTo方法非常简单:

public int compareTo(Person other) {
    int i = firstName.compareTo(other.firstName);
    if (i != 0) return i;

    i = lastName.compareTo(other.lastName);
    if (i != 0) return i;

    return Integer.compare(age, other.age);
}