Java的List集合按照對象的多個屬性排序

 

 

public class Employee { private int level; private int salary; private int years; public int getLevel() { return level; } public void setLevel(int level) { this.level = level; } public int getSalary() { return salary; } public void setSalary(int salary) { this.salary = salary; } public int getYears() { return years; } public void setYears(int years) { this.years = years; } @Override public String toString() { return "Employee [level=" + level + ", salary=" + salary + ", years=" + years + "]"; } } 

 

public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); List<Employee> list = new ArrayList<Employee>(); Employee e = new Employee(); e.setLevel(1); e.setSalary(300); e.setYears(4); list.add(e); e = new Employee(); e.setLevel(1); e.setSalary(500); e.setYears(4); list.add(e); e = new Employee(); e.setLevel(2); e.setSalary(500); e.setYears(4); list.add(e); e = new Employee(); e.setLevel(1); e.setSalary(300); e.setYears(5); list.add(e); // Collections.sort(list, new Comparator<Employee>() { // public int compare(Employee e2, Employee e1) { // int a = e1.getLevel() - e2.getLevel(); // if (a != 0) { // return a > 0 ? -1 : 1; // } // a = e1.getSalary() - e2.getSalary(); // if (a != 0) { // return a > 0 ? -1 : 1; // } // a = e1.getYears() - e2.getYears(); // return a > 0 ? -1 : 1; // } // });  Collections.sort(list, new Comparator<Employee>() { public int compare(Employee e1, Employee e2) { int a = e1.getLevel() - e2.getLevel(); if (a != 0) { return a > 0 ? 1 : -1; } a = e1.getSalary() - e2.getSalary(); if (a != 0) { return a > 0 ? 1 : -1; } a = e1.getYears() - e2.getYears(); return a > 0 ? 1 : -1; } }); // Employee [level=2, salary=500, years=4] // Employee [level=1, salary=500, years=4] // Employee [level=1, salary=300, years=5] // Employee [level=1, salary=300, years=4]  // Employee [level=1, salary=300, years=4] // Employee [level=1, salary=300, years=5] // Employee [level=1, salary=500, years=4] // Employee [level=2, salary=500, years=4]  // [level=1, salary=300, years=4] // [level=1, salary=300, years=5] // [level=1, salary=500, years=4] // [level=2, salary=500, years=4]  for (Employee em : list) { System.out.println(em); } } }