HashMap的使用

  import java.util.HashMap;
  import java.util.Map;
  /**
  测试HashMap的使用
  */
  public class TestMap {
  public static void main(String[] args) {
      //Test01();
      
      Employee e1 = new Employee(1001, "熊大", 10000);
      Employee e2 = new Employee(1002, "熊二", 20000);
      
      Map<Integer,Employee> map = new HashMap<>();
      
      map.put(1001, e1);  //使用map存储
      map.put(1002, e2);
      
      Employee emp = map.get(1001);
      System.out.println(emp.getEname());
      
  }
  
  public static void Test01() {
  Map<Integer,String> m1 = new HashMap<>();
  
  m1.put(1, "one");
  m1.put(2, "two");
  m1.put(3, "three");
      
  System.out.println(m1.get(1));
      
  System.out.println(m1.size());  //3
  System.out.println(m1.isEmpty());   //false
  System.out.println(m1.containsKey(2));  //true,是否包含2这个键
  System.out.println(m1.containsValue("four"));//false,是否包含four
      
  Map<Integer,String> m2 = new HashMap();
  m2.put(4,"si");
  m2.put(5,"wu");
      
  m1.putAll(m2);
      
  System.out.println(m1); //{1=one, 2=two, 3=three, 4=si, 5=wu}
      
  }  
}

class Employee {
    private int id;
    private String ename;
    private double salary;
    
  public Employee(int id, String ename, double salary) {
      super();
      this.id =id;
      this.ename = ename;
      this.salary = salary;
  }
  
  public String getEname() {
      return this.ename;
  }
  
}