jsp list排序的問題代碼-jsp入門

jsp教程 list排序的問題代碼-jsp入門

個list a和b,分別存有對象ob1,ob2。這兩個對象裡都有一個日期類型的欄位createTime。
現在要將a和b存入listc中，然後按照日期欄位createTime的值進行排序，

方法一

把你的對象實現Comparable介面，然後調用Collections.sort()方法就可以

利用自訂函數

package com.xuz.datastruct.csdn;

import java.util.Date;

public class MyClass implements Comparable<MyClass> {
    private Date d;

    public MyClass(Date d) {
        this.setD(d);
    }
   
    @Override
    public String toString(){
        return "my value is " + d;
    }

    @Override
    public int compareTo(MyClass o) {
        if (d.after(o.getD())) {
            return -1;
        }
       
        if (d.before(o.getD())) {
            return 1;
        }
       
        return 0;
    }

    public void setD(Date d) {
        this.d = d;
    }

    public Date getD() {
        return d;
    }
}

Collections.sort(list);

方法三

package com.xuz.datastruct.csdn;

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

public class CompareList {

    public static void main(String[] args) throws InterruptedException {
        List<MyClass> list = new ArrayList<MyClass>();
        list.add(new MyClass(Calendar.getInstance().getTime()));
        Thread.sleep(1000);
        list.add(new MyClass(Calendar.getInstance().getTime()));
        Thread.sleep(1000);
        list.add(new MyClass(Calendar.getInstance().getTime()));
        Thread.sleep(1000);
        list.add(new MyClass(Calendar.getInstance().getTime()));
        Thread.sleep(1000);
        list.add(new MyClass(Calendar.getInstance().getTime()));
        Thread.sleep(1000);
       
        for (MyClass myClass : list) {
            System.out.println(myClass);
        }
        System.out.println();
       
        Collections.sort(list);
       
        for (MyClass myClass : list) {
            System.out.println(myClass);
        }
    }

}