这个题真实变态 怎么改呐！！！

/**补充完该类,不修改main方法,使得get()方法可以取到值*/
package test;

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

public class StudentTest {
private static final class Student {
private static String name;

public Student(String name) {
this.name = name;
}

}


public static void main(String[] args) {
Map p = new HashMap();
p.put(new Student("lily"), "sister");
System.out.println(p.get("lily"));
System.out.print(p.keySet().iterator().next());
}
}

SORRY!  System.out.print(p.keySet().iterator().next()); 应该去掉

hashcode

请问能详细一点吗？
是重写Student类的hashCode()方法吗？

hashCode(){
return name.hashCode();
}

	private static final class Student {
		private static String name;

		public Student(String name) {
			this.name = name;
		}
		
		public int hashCode() {
			return this.name.hashCode();
		}

	}

试了一下

		Map p = new HashMap(); 
		Student tt = new Student("lily");
		p.put(tt, "sister");
		System.out.println(p.get("lily"));

null

		Map p = new HashMap(); 
		Student tt = new Student("lily");
		p.put(("lily", "sister");
		System.out.println(p.get("lily"));

sister

why???????

if(!(obj instanceof Test)) return false;
大约map先作这件事

public Object get(Object key) {
    Object k = maskNull(key);
    int hash = hash(k);
    int i = indexFor(hash, table.length);
    Entry e = table[i];
    while (true) {
       if (e == null)
           return e;
       if (e.hash == hash && eq(k, e.key))
           return e.value;
       e = e.next;
    }
 }

static int hash(Object x) {
     int h = x.hashCode();
     h += ~(h << 9);
     h ^= (h >>> 14);
     h += (h << 4);
     h ^= (h >>> 10);
     return h;
 } 

翻了一下 没找到类似语句

    public Object get(Object key) {
        Object k = maskNull(key);
        int hash = hash(k);
        int i = indexFor(hash, table.length);
        Entry e = table[i]; 
        while (true) {
            if (e == null)
                return e;
            if (e.hash == hash && eq(k, e.key)) 
                return e.value;
            e = e.next;
        }
    }

    public Object put(Object key, Object value) {
        Object k = maskNull(key);
        int hash = hash(k);
        int i = indexFor(hash, table.length);

        for (Entry e = table[i]; e != null; e = e.next) {
            if (e.hash == hash && eq(k, e.key)) {
                Object oldValue = e.value;
                e.value = value;
                e.recordAccess(this);
                return oldValue;
            }
        }

        modCount++;
        addEntry(hash, k, value, i);
        return null;
    }

刚开始怀疑是 indexFor 返回的不一样  可是test了一下 都是10


debug了一下
第一个情况  table里面是 Test$Student@32afca=sister
第二个情况  table里面是 lily=sister

走到了   是这句

if (e.hash == hash && eq(k, e.key))

通过统一定义equals()和hashCode()，
可以提升类作为基于散列的集合中的关键字的使用性
怎样写这两个方法呐？