List<Users> list = new ArrayList<Users>();
list.add(new Users("张三",442));
list.add(new Users("里斯",4544));
list.add(new Users("王五",244));
list.add(new Users("赵六",344));
list.add(new Users("夏吧",444));
list.add(new Users("初五",434));
list.add(new Users("一号",144));
请根据资金的大小进行一次排序!
list.add(new Users("张三",442));
list.add(new Users("里斯",4544));
list.add(new Users("王五",244));
list.add(new Users("赵六",344));
list.add(new Users("夏吧",444));
list.add(new Users("初五",434));
list.add(new Users("一号",144));
请根据资金的大小进行一次排序!
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int compare(Users o1, Users o2) {
return o1.编号 - o2.编号
}});
编号就是442的字段名
public int compare(Users user0, Users user1) {
user0.getAge().compareTo(user1.getAge());
return 0;
}
}
红色部分编译的时候出错:Cannot inVoke compare(int) on the primitive type int
list.add(new Users("张三",442));
list.add(new Users("里斯",4544));
list.add(new Users("王五",244));
list.add(new Users("赵六",344));
list.add(new Users("夏吧",444));
list.add(new Users("初五",434));
list.add(new Users("一号",144)); Set set = map.entrySet();
for(Iterator i = set.iterator();i.hasNext();)
{
Map.Entry entry = (Map.Entry)i.next();
list.add(entry);
}
Collections.sort(list,new Comparator()
{
public int compare(Object o1, Object o2) {
Map.Entry e1 = (Map.Entry)o1;
Map.Entry e2 = (Map.Entry)o2;
return Integer.parseInt(e1.getValue().toString())-Integer.parseInt(e2.getValue().toString());
}
}); list.reverse(); System.out.print("根据资金的大小:");
for(Iterator i = list.iterator();i.hasNext();)
{
Map.Entry entry = (Map.Entry)i.next();
System.out.print(entry.getKey()+":"+entry.getValue()+", ");
}
实现compareable接口就可以了...
将排序目标指向资金...
List<Users> list = new ArrayList<Users>();
list.add(new Users("张三",442));
list.add(new Users("里斯",4544));
list.add(new Users("王五",244));
list.add(new Users("赵六",344));
list.add(new Users("夏吧",444));
list.add(new Users("初五",434));
list.add(new Users("一号",144));
Collections.sort(list, new Comparator<Users>() {
public int compare(Users o1, Users o2) {
return o1.getAge() - o2.getAge();
} }); for (Users u : list) {
System.out.println(u.getAge());
}
Users类:
public class Users implements Comparable<Users> {
private String name;
private int age;
public Users(String name, int age) {
super();
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public int compareTo(Users u1) {
if(this.age > u1.getAge())
return 0;
else return 1;
}
}
java.util.Set<User> set = new java.util.TreeSet<User>(
new java.util.Comparator() {
public int compare(Object o1, Object o2) {
Integer p1 = ((Users)o1).getAge();
Integer p2 = ((Users)o2).getAge();
return p1 > p2 ? 1 : (p1 == p2 ? 0 : -1);
}
}
);
set.add(new Users("name1", 30));
set.add(new Users("name2", 40));
set.add(new Users("name3", 20));
set.add(new Users("name4", 80));
for (Users user : set) {
System.out.println(user.getName());
}
}