對集合進行排序

public class Test {
public static void main(String []args){


List<People> list = new ArrayList<People>();
People p1 = new People("zs","32");
People p2 = new People("ls","20");
People p3 = new People("ww","22");
People p4 = new People("ws","22");

list.add(p1);
list.add(p2);
list.add(p3);
list.add(p4);
PeopleCom pc = new PeopleCom();
Collections.sort(list,pc);

for(People p:list){
System.out.print(p.getName()+p.getAge()+"   ");
}
}

}

class PeopleCom implements Comparator{


public int compare(Object o1, Object o2) {
// TODO Auto-generated method stub
People p1 = (People)o1;
People p2 = (People)o2;

int flag = p1.getAge().compareTo(p2.getAge());
if(flag == 0){
return p1.getName().compareTo(p2.getName());
}
return flag;
}

}

class People{
private String name;
private String age;


public People(String name,String age){
this.name = name;
this.age = age;
}
public String getAge() {
return age;
}


public void setAge(String age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}

1.定義比較對象People

2.PeopleCom實現Comparator接口，定義比較規則

3.比較調用PeopleCom pc = new PeopleCom();Collections.sort(list,pc);