浅谈Java中Collections.sort对List排序的两种方法

 private void sortStrings() {
  List<String> list = new ArrayList<String>();
  list.add("ccc");
  list.add("aaa");
  list.add("bbb");
  //排序
  Collections.sort(list);
  //输出
  Log.d(TAG, "-----------对字符串排序-----------");
  for(String item : list) {
   Log.d(TAG, item.toString());
  }
 }

public class Person {
 
 private String name;
 private int age;
 
 public Person(String name, int age) {
  this.name = name;
  this.age = age;
 }
}

 private void sortPerson() {
  Person p1 = new Person("ccc", 20);
  Person p2 = new Person("aaa", 18);
  Person p3 = new Person("bbb", 16);
  
  List<Person> list = new ArrayList<Person>();
  list.add(p1);
  list.add(p2);
  list.add(p3);
  
  //排序
  Collections.sort(list);
 }

public class Person implements Comparable<Person> {
 
 public String name;
 public int age;
 
 public Person(String name, int age) {
  this.name = name;
  this.age = age;
 }
 
 public int compareTo(Person another) {
  int i = name.compareTo(another.name); //比较名字字符串
  if (i == 0) { //如果名字一样，则继续比较年龄
   return age - another.age;
  } else { //首先比较名字，名字不一样，则返回比较结果
   return i;
  }
 }
}

 private void sortByComparable() {
  Person p1 = new Person("bbb", 20);
  Person p2 = new Person("aaa", 18);
  Person p3 = new Person("bbb", 16);
  
  List<Person> list = new ArrayList<Person>();
  list.add(p1);
  list.add(p2);
  list.add(p3);
  
  //排序
  Collections.sort(list);
  //输出
  Log.d(TAG, "-----------使用Comparable实现的排序-----------");
  for(Person item : list) {
   Log.d(TAG, "name = "+item.name+", age = "+item.age);
  }
 }

public class Person {
 
 public String name;
 public int age;
 
 public Person(String name, int age) {
  this.name = name;
  this.age = age;
 }
}

 public class MyComparator implements Comparator<Person> {
 
  public int compare(Person one, Person two) {
   int i = one.name.compareTo(two.name); //比较名字字符串
   if (i == 0) { //如果名字一样，则继续比较年龄
    return one.age - two.age;
   } else { //首先比较名字，名字不一样，则返回比较结果
    return i;
   }
  }
  
 }

 private void sortByComparator() {
  Person p1 = new Person("bbb", 20);
  Person p2 = new Person("aaa", 18);
  Person p3 = new Person("bbb", 16);
  
  List<Person> list = new ArrayList<Person>();
  list.add(p1);
  list.add(p2);
  list.add(p3);
  
  //排序
  Collections.sort(list, new MyComparator());
  //输出
  Log.d(TAG, "-----------使用Comparator实现的排序-----------");
  for(Person item : list) {
   Log.d(TAG, "name = "+item.name+", age = "+item.age);
  }
 }