java内置排序简易使用记录

主要记录Comparator Comparable这两个类的使用：

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

public class T {

public static void main(String[] args) {
List<A> list = new ArrayList<A>();
A a1 = new A();
a1.setFlag(1);
A a2 = new A();
a2.setFlag(4);
A a3 = new A();
a3.setFlag(2);
A a4 = new A();
a4.setFlag(3);
list.add(a1);
list.add(a2);
list.add(a3);
list.add(a4);
for(A a:list){
System.out.println(a.getFlag());
}
System.out.println("--------------");


Collections.sort(list,new Comparator<A>() {
@Override
public int compare(A o1, A o2) {
return o1.flag>o2.flag?1:-1;
}
});

for(A a:list){
System.out.println(a.getFlag());
}
Collections.sort(list);

for(A a:list){
System.out.println(a.getFlag());
}
}
}


class A implements Comparable<A>{
int flag;
String name;


public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public int getFlag() {
return flag;
}

public void setFlag(int flag) {
this.flag = flag;
}

@Override
public int compareTo(A o) {
return this.flag>o.flag?-1:1;
}


}