HashMap

    package list;  
      
    import java.util.Collection;  
    import java.util.HashMap;  
    import java.util.Map;  
    import java.util.Set;  
      
    public class MapTest {  
        public static void main(String[] args) {  
            Map<String, Employee> staff = new HashMap<String, Employee>();  
            staff.put("144-25-5464", new Employee("Amy"));  
            staff.put("567-24-2546", new Employee("Harry"));  
            staff.put("157-62-7935", new Employee("Gray"));  
            staff.put("456-62-5527", new Employee("France"));  
            System.out.println(staff);  
              
            staff.remove("567-24-2546");//删除  
            System.out.println(staff);  
              
            staff.put("456-62-5527", new Employee("Bob"));//替换  
            System.out.println(staff);  
              
            System.out.println(staff.get("157-62-7935"));//查询  
              
            //取得map中所有的key和value  
            for(Map.Entry<String, Employee> entry : staff.entrySet()) {  
                String key = entry.getKey();  
                Employee value = entry.getValue();  
                System.out.println("key=" + key + ", value=" + value + "");  
            }  
              
            //取得map中所有的key  
            Set<String> keys = staff.keySet();  
            for(String key : keys) {  
                System.out.println(key);  
            }  
              
            //取得map中所有的value  
            Collection<Employee> values = staff.values();  
            for(Employee value : values) {  
                System.out.println(value);  
            }  
        }  
    }  
      
    class Employee {  
        public Employee(String n) {  
            name = n;  
            salary = 0;  
        }  
          
        public String toString() {  
            return "[name=" + name + ", salary=" + salary + "]";  
        }  
          
        private String name;  
        private double salary;  
    }