错误: Student不是抽象的, 并且未覆盖Comparable中的抽象方法compar eTo(Student)
import java.util.*;class Student implements Comparable<Student>
{
private String name;
private int age;
Student(String name, int age)
{
this.name = name;
this.age = age;
}
public int compareTO(Student s)
{
int num = new Integer(this.age).compareTO(new Integer(s.age));
if(num==0)
return this.(s.name);
return num;
}
public int hashCode()
{
return name.hashCode()+age*34;
}
public boolean equals(Object obj)
{
if(!(obj instanceof Student))
throw new ClassCastException("类型不匹配");
Student s = (Student)obj;
return this.name.equals(s.name) && this.age==s.age;
}
public String getName()
{
return name;
}
public int getAge()
{
return age;
}
public String toString()
{
return name+":"+age;
}
}
class MapTest
{
public static void main(String[] args)
{
HashMap<Student,String> hm = new HashMap<Student,String>();
hm.put(new Student("lisi1"),"beijing");
hm.put(new Student("lisi2"),"shanghai");
hm.put(new Student("lisi3"),"nanjing");
hm.put(new Student("lisi4"),"wuhan");
//第一种取出方式 keySet
Set<Student> keySet = hm.keySet();
Iterator<Student> it = keySet.iterator();
while(it.hashNext())
{
Student stu = it.next();
String addr = hm.get(stu);
System.out.println(stu+".."+addr);
}
}
}