public interface Comparable {int compareTo(Object obj);
}
public class News implements Comparable{private int nid;//编号private String title; //标题private String contents;//内容private String  type;//新闻类别public News() {}public News(int nid, String title, String contents,String type) {super();this.nid = nid;this.title = title;this.contents = contents;this.type = type;      }/*** 按照新闻编号正序排列*/public int compareTo(Object obj) {News other =(News)obj;return this.nid- other.nid;          }@Overridepublic String toString() {return "News [nid=" + nid + ", title=" + title + ", contents="+ contents + ", type=" + type + "]";}}
public class Student implements Comparable{private int id;private String name;private int age;private double score; public Student() {super();}public Student(int id, String name, int age, double score) {super();this.id = id;this.name = name;this.age = age;this.score = score;}/*** 按照学生成绩降序排序*/public int compareTo(Object obj) {Student other =(Student)obj;if(this.score>other.score){return -1;}else if(this.score<other.score){return 1;}else{return 0;}}@Overridepublic String toString() {return "Student [id=" + id + ", name=" + name + ", age=" + age+ ", score=" + score + "]";}
}//测试类
public class Test {public static void main(String[] args) {//Student stu1 = new Student(11, "小红", 18, 97d);Student stu2 = new Student(12, "小东", 20, 98d);if(stu1.compareTo(stu2)>0){           System.out.println(stu2);System.out.println(stu1);}else{System.out.println(stu1);System.out.println(stu2);}//News news1 = new News(33, "恒大亚冠", "恒大亚冠小组被淘汰", "体育");News news2 = new News(44, "上海尚学堂", "请原谅我的姗姗来迟", "IT");if(news1.compareTo(news2)>0){System.out.println(news2);System.out.println(news1);          }else{System.out.println(news1);System.out.println(news2);}}
}