import java.util.*;class User
{
String userName;
int money; public User(String userName,int money)
{
this.userName = userName;
this.money = money; }
public String getName()
{
return userName; }
public int money()
{
return money;
} public String toString()
{
return "用户名:"+userName+"帐目:"+money;
}
}
public class HandleBank
{
public static void main(String[]args)throws Exception
{
User u1 = new User("haifei",900);
User u2 = new User("haixiang",300);
User u3 = new User("haiyan",600);
User u4 = new User("haihua",500); List list = new ArrayList(); list.add(u1);
list.add(u2);
list.add(u3);
list.add(u4);
for (int i = 0;i<list.size() ;i++ )
{
//User user = (User)list.get(i);
Collections.sort(list);
System.out.println(list);
}
}
}
{
String userName;
int money; public User(String userName,int money)
{
this.userName = userName;
this.money = money; }
public String getName()
{
return userName; }
public int money()
{
return money;
} public String toString()
{
return "用户名:"+userName+"帐目:"+money;
}
}
public class HandleBank
{
public static void main(String[]args)throws Exception
{
User u1 = new User("haifei",900);
User u2 = new User("haixiang",300);
User u3 = new User("haiyan",600);
User u4 = new User("haihua",500); List list = new ArrayList(); list.add(u1);
list.add(u2);
list.add(u3);
list.add(u4);
for (int i = 0;i<list.size() ;i++ )
{
//User user = (User)list.get(i);
Collections.sort(list);
System.out.println(list);
}
}
}
at java.util.Arrays.mergeSort(Arrays.java:1156)
at java.util.Arrays.sort(Arrays.java:1080)
就抛出这样的异常信息
请高手指教
java.lang.ClassCastException异常
public static void main(String[] args) throws Exception {
User u1 = new User("haifei", 900);
User u2 = new User("haixiang", 300);
User u3 = new User("haiyan", 600);
User u4 = new User("haihua", 500); List list = new ArrayList(); list.add(u1);
list.add(u2);
list.add(u3);
list.add(u4); Collections.sort(list);
System.out.println(list);
}
}class User implements Comparable {
private String userName;
private int money; public User(String userName, int money) {
this.userName = userName;
this.money = money;
} public String getName() {
return userName;
} public int getMoney() {
return money;
} public String toString() {
return "User Name:" + userName + "Money:" + money;
}
public int compareTo(Object o) {
if (money > ((User)o).money)
return 1;
else if (money < ((User)o).money)
return -1;
return 0;
}}
class TestSort
{
public static void main(String[] args)
{
ArrayList al = new ArrayList();
al.add(new Integer(1));
al.add(new Integer(3));
al.add(new Integer(5));
al.add(new Integer(2));
al.add(new Integer(4));
al.add(new Integer(7));
al.add(new Integer(6));
Collections.sort(al); System.out.println(al.toString());
}
}这个怎么不要重写接口 Comparator中的CompareTo()方法,