ArrayList、HashMap 与 员工类（程序员、经理的结合使用） 相当于集合与继承的总结

 package Day28ketangzuoye;

 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Map;

 public class EmployeeTest {

     public static void main(String[] args) {
         Emp se1=new SE(0001,"蔡正",true,6000,80);
         Emp se2=new SE(0002,"丁陆",true,7000,89);

         Emp pm1=new PM(1001,"王拥江",true,9000,"一年",3000);
         Emp pm2=new PM(1002,"贝杰明",true,13000,"七年",5000);

         System.out.println("ArrayList");
         ArrayList<Emp> list=new ArrayList<Emp>();
         list.add(se1);
         list.add(se2);
         list.add(pm1);
         list.add(pm2);
         SE e;
         PM m;
         for(Emp p:list){
             if(p instanceof SE){
                 e=(SE)p;
                 e.show();
             }else if(p instanceof PM){
                 m=(PM)p;
                 m.show();
             }else{
                 System.out.println("出错！");
             }
         }

         System.out.println("\n\n HashMap");
         Map<String,Emp> map=new HashMap<String,Emp>();
         map.put("蔡正",se1);
         map.put("丁陆",se2);
         map.put("王拥江",pm1);
         map.put("贝杰明",pm2);
         String[] str={"蔡正","丁陆","王拥江","贝杰明"};
         Emp p;
         for(int i=0;i<map.size();i++){
              p=map.get(str[i]);
             if(p instanceof SE){
                 e=(SE)p;
                 e.show();
             }else if(p instanceof PM){
                 m=(PM)p;
                 m.show();
             }else{
                 System.out.println("出错！");
             }
         }

     }
 }

 class Emp {
     public  int id;
     public  String name;
     public  boolean gender;
     public  double salary;

     public Emp() {
         super();
     }

     public Emp(int id, String name, boolean gender, double salary) {
         super();
         this.id = id;
         this.name = name;
         this.gender = gender;
         this.salary = salary;
     }

     public void show(){};
 }

 class SE extends Emp {
     int hot;

     public SE(int id, String name, boolean gender, double salary,int hot) {
         super(id,name,gender,salary);
         this.hot = hot;
     }

     @Override
     public void show() {
         System.out.println("SE [id=" + id + ", name=" + name + ", gender="
                 + gender + ", salary=" + salary + ", hot=" + hot + "]");
     }
 }

 class PM extends Emp{
     String exp;
     double bonus;

     public PM(int id, String name, boolean gender, double salary,String exp, double bonus) {
         super(id,name,gender,salary);
         this.exp = exp;
         this.bonus = bonus;
     }

     @Override
     public void show() {
         System.out.println("PM [id=" + id + ", name=" + name + ", gender="
                 + gender + ", salary=" + salary + ", exp=" + exp + ", bonus=" + bonus + "]");
     }
 }

 ArrayList
 SE [id=1, name=蔡正, gender=true, salary=6000.0, hot=80]
 SE [id=2, name=丁陆, gender=true, salary=7000.0, hot=89]
 PM [id=1001, name=王拥江, gender=true, salary=9000.0, exp=一年, bonus=3000.0]
 PM [id=1002, name=贝杰明, gender=true, salary=13000.0, exp=七年, bonus=5000.0]

  HashMap
 SE [id=1, name=蔡正, gender=true, salary=6000.0, hot=80]
 SE [id=2, name=丁陆, gender=true, salary=7000.0, hot=89]
 PM [id=1001, name=王拥江, gender=true, salary=9000.0, exp=一年, bonus=3000.0]
 PM [id=1002, name=贝杰明, gender=true, salary=13000.0, exp=七年, bonus=5000.0]