java中TreeMap用例，并加入比较器排序

快来打我* 2022-06-17 05:16 40阅读 0赞

package itcast04;
    
    import java.util.Comparator;
    import java.util.Set;
    import java.util.TreeMap;
    
    import itcast02.Student;
    
    /**
     * TreeMap<Student, String>
     * 键：Student
     * 值：String
     * 并加入比较器排序
     * @author lgt
     *
     */
    public class TreeDemo2 {
        
        public static void main(String[] args) {
            //创建集合对象
            TreeMap<Student, String> tm = new TreeMap<Student, String>(
                    new Comparator<Student>() {
                        @Override
                        public int compare(Student s1, Student s2) {
                            //主要条件 按年龄排序
                            int num = s2.getAge() - s1.getAge();
    
                            //次要条件 姓名是否相同
                            int num2 = num == 0?s1.getName().compareTo(s2.getName()) : num;
    
                            return num2;
                        }
            });
    
            //创建学生对象
            Student s1 = new Student("周星驰", 58);
            Student s2 = new Student("刘德华", 56);
            Student s3 = new Student("梁朝伟", 54);
            Student s4 = new Student("刘嘉玲", 50);
            Student s5 = new Student("刘德华", 56);
    
            //存储元素
            tm.put(s1, "北京");
            tm.put(s2, "上海");
            tm.put(s3, "广州");
            tm.put(s4, "深圳");
            tm.put(s5, "杭州");
    
            //遍历
            Set<Student> set = tm.keySet();
            for(Student key : set){
                String value = tm.get(key);
                System.out.println(key.getName() + "---" + key.getAge() + "---"
                        + value);
            }
        }
    }