Timer启动一个定时任务

package com.itheima74.test;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Date;import java.util.Timer;import java.util.TimerTask;public class MainActivity extends AppCompatActivity {    @Override    PRotected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        // 指定任务运行时间        String time_str = "2017-02-26 17:15:00.000";        // MM:必须大写,HH:代表24小时制,SSS:毫秒        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");        long time_long = 0;        try {            // 将指定时间转化为long类型数据            time_long = simpleDateFormat.parse(time_str).getTime();        } catch (ParseException e) {            e.printStackTrace();        }        System.out.println("time:" + time_long);        // 创建一个定时任务,指定此刻运行此任务        Timer timer = new Timer();        Date date = new Date(time_long);        timer.schedule(new TimerTask() {            @Override            public void run() {                System.out.println("哈哈,我被执行了");            }        }, date);    }}