List的排序算法

最近在一个项目中遇到需要将一个list集合根据时间进行排序的情况，于是，写出了以下方法，为了便于展示方法，我们首先建一个实体类

package test;

import java.util.Date;

public class User {
private int userid;
private String username;
private Date BirthDatestr;
private int num;
public int getUserid() {
return userid;
}
public void setUserid(int userid) {
this.userid = userid;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Date getBirthDatestr() {
return BirthDatestr;
}
public void setBirthDatestr(Date birthDatestr) {
BirthDatestr = birthDatestr;
}
public int getNum() {
return num;
}
public void setNum(int num) {
this.num = num;
}
public UserInfo(int userid, String username, Date birthDatestr,
int num) {
super();
this.userid = userid;
this.username = username;
BirthDatestr = birthDatestr;
this.num = num;
}

}

package test;

import java.util.Date;

public class User {
	private int userid;
	private String username;
	private Date BirthDatestr;
	private int num;
	public int getUserid() {
		return userid;
	}
	public void setUserid(int userid) {
		this.userid = userid;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public Date getBirthDatestr() {
		return BirthDatestr;
	}
	public void setBirthDatestr(Date birthDatestr) {
		BirthDatestr = birthDatestr;
	}
	public int getNum() {
		return num;
	}
	public void setNum(int num) {
		this.num = num;
	}
	public UserInfo(int userid, String username, Date birthDatestr, int num) {
		super();
		this.userid = userid;
		this.username = username;
		BirthDatestr = birthDatestr;
		this.num = num;
	}
	
}

之后是排序方法

import java.lang.reflect.InvocationTargetException;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.lang.reflect.Method;

public class SortList<E>{
public void Sort(List<E> list,
final String method, final String sort){
Collections.sort(list, new Comparator() {
public int compare(Object a, Object b) {
int ret = 0;
try{
Method m1 = ((E)a).getClass().getMethod(method, null);
Method m2 = ((E)b).getClass().getMethod(method, null);
if(sort != null && 
"desc".equals(sort))//倒序
ret = m2.invoke(((E)b), null).toString().compareTo(m1.invoke(((E)a),
null).toString());
else//正序
ret = m1.invoke(((E)a), null).toString().compareTo(m2.invoke(((E)b),
null).toString());
}catch(NoSuchMethodException ne){
System.out.println(ne);
}catch(IllegalAccessException ie){
System.out.println(ie);
}catch(InvocationTargetException it){
System.out.println(it);
}
return ret;
}
});
}
}