2021-09-27 Map练习：授课教师+去重计数

 两个编程题：

package TXT.CodeTest;

import com.sun.org.apache.bcel.internal.generic.ALOAD;

import java.util.*;


public class Test {
    public static void main(String[] args) {
        method2();
    }
    
    public static void method1(){
        Map course = new HashMap<>();
        course.put("Lucy","JSP");
        course.put("Kevin","JSP");
        course.put("Jim","Unix");
        course.put("Jerry","JDBC");
        course.put("Susan","Oracle");
        course.put("John","Oracle");
        course.put("Tom","CoreJava");
        //1、
        System.out.println(course);
        //2、
        course.put("Allen","JDBC");
        System.out.println("Allen教授的科目为："+course.get("Allen"));
        //3、
        course.put("Lucy","CoreJava");
        System.out.println("Lucky教授的科目为："+course.get("Lucy"));
        //4、
        Set> info = course.entrySet();
        for (Map.Entry lesson:info ) {
            System.out.println("授课教师："+lesson.getKey()+" t教授科目："+lesson.getValue());
        }
        //5、
        System.out.print("教授JSP科目的老师有：");
        for (Map.Entry lesson:info) {
            if(lesson.getValue().equals("JSP")){
                System.out.print(lesson.getKey()+" ");
            }
        }
    }
    
    public static void method2(){
        String str = "adhflkalkfdhasdkhflsa";
        Map map = new HashMap<>();
        for (int i = 0; i