除了利用数据库的sql语句排序还可以利用java的Comparable接口自定义排序。
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class Employee implements Comparable<Employee> {
private int id;
private String name;
private int age;
public Employee(int id,String name,int age){
this.id = id;
this.name = name;
this.age = age;
}
@Override
public int compareTo(Employee o) {
// TODO Auto-generated method stub
if(id>o.id){
return 1;
}else if(id<o.id){
return -1;
}
return 0;
}
@Override
public String toString() {
// TODO Auto-generated method stub
StringBuilder sb = new StringBuilder();
sb.append("员工的编号"+id);
sb.append("员工的姓名"+name);
sb.append("员工的年龄"+age);
return sb.toString();
}
public static void main(String[] args) {
List<Employee> list = new ArrayList<Employee>();
list.add(new Employee(3,"java",21));
list.add(new Employee(31,"java1",22));
list.add(new Employee(32,"java2",24));
list.add(new Employee(28,"java6",25));
for(Employee hh:list){
System.out.println(hh);
}
Collections.sort(list);
for(Employee zz:list){
System.out.println(zz);
}
System.out.println();
}
}