Java_集合_ArrayLish Comparator比较排序 小笔记

 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;

 class Teacher_Main {
     public static void main(String[] args) {

         ArrayList<Teacher> teacherList = new ArrayList<Teacher>();
         teacherList.add(new Teacher("污老湿", 35));
         teacherList.add(new Teacher("污老人", 15));
         teacherList.add(new Teacher("污小人", 7));
         teacherList.add(new Teacher("污大人", 99));

         Collections.sort(teacherList, new Comparator<Teacher>() {

             @Override
             public int compare(Teacher o1, Teacher o2) {
               if (o1.age > o2.age) {
                     return -1;
             } else if (o1.age < o2.age) {
                     return 1;
                 }
                 　　 return 0;
             }

         });
         for (int i = 0; i < teacherList.size(); i++) {
            　　 Teacher teacher = teacherList.get(i);
             　　System.out.println(teacher);

         }
     }
 }

 class Teacher {
     public String name;
     public int age;

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

     @Override
     public String toString()/*转成字符串类型*/ {
         return name + ":" + +age;
     }

 }