java List 排序 Collections.sort() 对 List 排序(首先年龄排序，如果年龄相同，则按名字排序)

第一种

/* * Collections可以针对ArrayList存储基本包装类的元素排序，存储自定义对象可不可以排序呢? */public class CollectionsDemo {	public static void main(String[] args) {		// 创建集合对象		List<Student> list = new ArrayList<Student>();		// 创建学生对象		Student s1 = new Student("linqingxia", 27);		Student s2 = new Student("风清扬", 30);		Student s3 = new Student("刘晓曲", 28);		Student s4 = new Student("武鑫", 29);		Student s5 = new Student("caiming", 27);		// 添加元素对象		list.add(s1);		list.add(s2);		list.add(s3);		list.add(s4);		list.add(s5);		// 排序		// 自然排序		// Collections.sort(list);		// 比较器排序		// 如果同时有自然排序和比较器排序，以比较器排序为主		Collections.sort(list, new Comparator<Student>() {			@Override			public int compare(Student s1, Student s2) {				  if(s1.getAge()-(s2.getAge())!=0){				       return s1.getAge()-(s2.getAge());				    }else{				       return  s1.getName().compareTo(s2.getName());				     }			}		});		// 遍历集合		for (Student s : list) {			System.out.PRintln(s.getName() + "---" + s.getAge());		}	}}public class Student  {	private String name;	private int age;	public Student() {		super();	}	public Student(String name, int age) {		super();		this.name = name;		this.age = age;	}	public String getName() {		return name;	}	public void setName(String name) {		this.name = name;	}	public int getAge() {		return age;	}	public void setAge(int age) {		this.age = age;	}}第二种
public class User { private int age; private String name;  public User(String name,int age){  this.name=name;  this.age=age; } public int getAge() {  return age; } public void setAge(int age) {  this.age = age; } public String getName() {  return name; } public void setName(String name) {  this.name = name; }}   //具体的比较类，实现Comparator接口  public class ComparatoUser implements Comparator {  public int compare(Object arg0, Object arg1) {    User user0=(User)arg0;    User user1=(User)arg1;//     首先比较年龄，如果年龄相同，则比较名字   int flag=user0.getAge()-(user1.getAge());    if(flag==0){     return user0.getName().compareTo(user1.getName());    }else{     return flag;    }    }}    //测试类 public class TestUser { public static void main(String[] args){  List list=new ArrayList();  list.add(new User("aa",12));  list.add(new User("dd",888));  list.add(new User("ff",123));  list.add(new User("cc",123));  list.add(new User("bb",142));  list.add(new User("ww",126));     主要看看拿的那个对象  ComparatoUser com=new ComparatoUser();  Collections.sort(list, com);      for(int i=0;i<list.size();i++){   User u=(User)list.get(i);   System.out.print(u.getAge()+"/");   System.out.println(u.getName());  } }}