departmentList = departmentService.findAll(); Collections.sort(departmentList, new CompartorDepartment());public class CompartorDepartment extends Department implements Comparator { private static final long serialVersionUID = 1L; public CompartorDepartment() { } public int compare(Object a, Object b) { Department s1 = (Department) a; Department s2 = (Department) b; return s1.getId() - s2.getId() < 0 ? -1 : 1; } }
Collections.sort(list, new Comparator<对象>(){ public int compare(对象 o1, 对象 o2) { return o1.getAge()>o2.getAge()?1 :(o1.getAge()<o2.getAge()?-1:0); } });
示例按birthday属性排序import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.Date; import java.util.List;public class Test { public static class Man { private String birthday; private String name; public Man() { } public Man(String name, String birthday) { this.name = name; this.birthday = birthday; } @Override public String toString() { return name + " " + birthday; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getBirthday() { return birthday; } public void setBirthday(String birthday) { this.birthday = birthday; } } public static void main(String[] args) { List<Man> list = new ArrayList<Man>(); list.add(new Man("张三", "2000-01-01 20:20:20")); list.add(new Man("李四", "2001-01-01 20:20:20")); list.add(new Man("王五", "2005-05-01 20:20:20")); list.add(new Man("BBB", "2003-01-01 20:20:20")); System.out.println("排序前:" + list); Collections.sort(list, new Comparator<Man>() { SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss"); private Date getBirthday(Man m) { if (m == null || m.getBirthday() == null) return null; try { return sdf.parse(m.getBirthday()); } catch (ParseException e) { return null; } } public int compare(Man o1, Man o2) { Date d1 = getBirthday(o1); Date d2 = getBirthday(o2); if (d1 == null && d2 == null) return 0; if (d1 == null) return -1; if (d2 == null) return 1; return d1.compareTo(d2); } }); System.out.println("排序后:" + list); }}
departmentList = departmentService.findAll();
Collections.sort(departmentList, new CompartorDepartment());public class CompartorDepartment extends Department implements Comparator
{
private static final long serialVersionUID = 1L; public CompartorDepartment()
{ } public int compare(Object a, Object b)
{
Department s1 = (Department) a;
Department s2 = (Department) b;
return s1.getId() - s2.getId() < 0 ? -1 : 1; }
}
Collections.sort(list, new Comparator<对象>(){
public int compare(对象 o1, 对象 o2)
{
return o1.getAge()>o2.getAge()?1 :(o1.getAge()<o2.getAge()?-1:0);
}
});
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.List;public class Test { public static class Man { private String birthday;
private String name; public Man() {
} public Man(String name, String birthday) {
this.name = name;
this.birthday = birthday;
} @Override
public String toString() {
return name + " " + birthday;
} public String getName() {
return name;
} public void setName(String name) {
this.name = name;
} public String getBirthday() {
return birthday;
} public void setBirthday(String birthday) {
this.birthday = birthday;
}
} public static void main(String[] args) {
List<Man> list = new ArrayList<Man>();
list.add(new Man("张三", "2000-01-01 20:20:20"));
list.add(new Man("李四", "2001-01-01 20:20:20"));
list.add(new Man("王五", "2005-05-01 20:20:20"));
list.add(new Man("BBB", "2003-01-01 20:20:20")); System.out.println("排序前:" + list);
Collections.sort(list, new Comparator<Man>() { SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss"); private Date getBirthday(Man m) {
if (m == null || m.getBirthday() == null)
return null;
try {
return sdf.parse(m.getBirthday());
} catch (ParseException e) {
return null;
}
} public int compare(Man o1, Man o2) {
Date d1 = getBirthday(o1);
Date d2 = getBirthday(o2);
if (d1 == null && d2 == null)
return 0; if (d1 == null)
return -1;
if (d2 == null)
return 1;
return d1.compareTo(d2);
} });
System.out.println("排序后:" + list);
}}