s-day04-接口回调案例

s-day04/src/com/inmind/sort05/SortDemo12.java

@@ -1,27 +1,96 @@
 package com.inmind.sort05;
 
-import java.util.Arrays;
+import com.inmind.treeset02.Student;
+
+import java.util.*;
 
 /*
 冒泡排序
+
+接口回调：帮助大家理解比较器Comparator，如果实现排序功能
+
+接口回调的原理功能：将我们自定义的业务逻辑，嵌入到源码中！！！！
  */
 public class SortDemo12 {
     public static void main(String[] args) {
         //创建一个数组
-        int[] arr = {1, 5, 3, 4, 2};
+        Integer[] arr = {1, 5, 3, 4, 2};
         //5个数字，要排4趟
+        sort(arr,new Comparator<Integer>(){
+
+            @Override
+            public int compare(Integer o1, Integer o2) {
+                //return o1-o2;//升序
+                return o2-o1;
+            }
+        });
+
+        System.out.println(Arrays.toString(arr));
+
+        System.out.println("--------------------------");
+        Student[] students = {
+                new Student("小王1", 15),
+                new Student("小王2", 19),
+                new Student("小王3", 17),
+                new Student("小王4", 18),
+                new Student("小王5", 16)
+        };
+
+        sort(students, new Comparator<Student>() {
+            @Override
+            public int compare(Student o1, Student o2) {
+                return o2.age - o1.age;
+            }
+        });
+        System.out.println(Arrays.toString(students));
+        System.out.println("----------------------");
+        ArrayList<Student> list = new ArrayList<>();
+        Collections.addAll(list,
+                new Student("小王1", 15),
+                new Student("小王2", 19),
+                new Student("小王3", 17),
+                new Student("小王4", 18),
+                new Student("小王5", 16));
+
+        sortList(list, new Comparator<Student>() {
+            @Override
+            public int compare(Student o1, Student o2) {
+                return o2.age - o1.age;
+            }
+        });
+        System.out.println(list);
+    }
+
+    //定义一个排序方法，接收一个需要排序的整数数组，和一个比较器Comparator
+    public static <T> void sort(T[] arr, Comparator<T> comparator) {
         for (int i = 0; i < arr.length - 1; i++) {//循环4次
             //每趟排序的次数刚好就是arr.length - 1-i
             for (int j = 0; j < arr.length - 1 - i; j++) {
                 //每趟中每次都是相邻比较,如果大或者小就往后（升序，降序）
-                if (arr[j] < arr[j + 1]) {
+//                if (arr[j] -arr[j + 1] > 0 ) {
+                if (comparator.compare(arr[j], arr[j + 1]) > 0 ) {
                     //交换
-                    int temp = arr[j];
+                    T temp = arr[j];
                     arr[j] = arr[j + 1];
                     arr[j+1] = temp;
                 }
             }
         }
-        System.out.println(Arrays.toString(arr));
+    }
+
+    public static <T> void sortList(List<T> arr, Comparator<T> comparator) {
+        for (int i = 0; i < arr.size() - 1; i++) {//循环4次
+            //每趟排序的次数刚好就是arr.length - 1-i
+            for (int j = 0; j < arr.size() - 1 - i; j++) {
+                //每趟中每次都是相邻比较,如果大或者小就往后（升序，降序）
+//                if (arr[j] -arr[j + 1] > 0 ) {
+                if (comparator.compare(arr.get(j), arr.get(j+1)) > 0 ) {
+                    //交换
+                    T temp = arr.get(j);
+                    arr.set(j, arr.get(j+1));
+                    arr.set(j = 1, temp);
+                }
+            }
+        }
     }
 }

s-day04/src/com/inmind/treeset02/Student.java

@@ -3,8 +3,8 @@ package com.inmind.treeset02;
 import java.util.Objects;
 
 public class Student implements Comparable<Student>{
-    String name;
+    public String name;
-    int age;
+    public int age;
 
     public Student(String name, int age) {
         this.name = name;