Java中实现对象的比较

Java中通过接口实现两个对象的比较，首先类要实现comparable接口，使用泛型规定了要进行比较的对象所属的类，而comparable接口的实现必须要定义的方法则是compareTo方法，在方法中传入此类的另一个对象，通过选定的成员变量与之比较，如果大于则返回1，小于返回-1，相等返回0.

例子代码：

package com.study.write; import java.util.*; public class EmployeeSortTest { public static void main(String[] args) { Employee2[] staff = new Employee2[3]; staff[0] = new Employee2("Harry", 35000); staff[1] = new Employee2("Danny", 40000); staff[2] = new Employee2("Tony", 20000); Arrays.sort(staff); //print out information about all Employee objects for(Employee2 e:staff) System.out.println("name = " + e.getName() +" " + "salary = " + e.getSalary()); } } class Employee2 implements Comparable<Employee2> { public Employee2(String n, double s) { name = n; salary = s; } public String getName() { return name; } public double getSalary() { return salary; } public void raiseSalary(double byPecent) { double raise = salary * byPecent / 100; salary += raise; } /**compares employees by salary @param other another Employee object @return a negative value if this employee has a lower salary than otherObject, 0 if the salaries are the same, a positive value otherwise */ public int compareTo(Employee2 other) { if(salary < other.salary) return -1; if(salary > other.salary) return 1; return 0; } private String name; private double salary; }

 

运行结果为：