使用 hashMap和treeMap开启多个摄像头的监控任务

 

 

背景：今天有个需求，传入多个摄像头ID，然后调用接口，开启这些摄像头的监控任务。

 

方法一：

如果你的摄像头监控任务格式为：

{camera_id_list=[{createBy=tjt, cameraId=camera01, startTime=2019-1-10 22:58:19}, {createBy=tjt, cameraId=camera02, startTime=2019-1-10 22:58:19}], callback=http://www.baidu.com}

这种格式的话，那么可以用hashMap搞定。

代码如下：

import java.util.Date;
import java.util.HashMap;
import java.util.LinkedList;

import org.apache.commons.lang.time.DateFormatUtils;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public class HashMapUtil {
    
    public static void main(String[] args) {
        HashMapUtil.testHashMap("camera01,camera02,camera03");
    }
    
    public static void testHashMap(String cameraStrList) {
        String[] splitCameraList = cameraStrList.split(",");
        HashMap<String, Object> hashMap = new HashMap<>();
        //add and delete faster than arrayList when using linkList
        LinkedList<Object> linkedList = new LinkedList<>();
        for(String splitCamera : splitCameraList) {
            hashMap.put("cameraId", splitCamera);
            hashMap.put("createBy","tjt");
            hashMap.put("startTime", DateFormatUtils.format(new Date(), "yyyy-MM-dd HH:mm:ss"));
            linkedList.add(hashMap);
            hashMap = new HashMap<>();
        }
        HashMap<Object, Object> paramMap = new HashMap<>();
        paramMap.put("camera_id_list", linkedList);
        paramMap.put("callback", "http://www.baidu.com");
        log.info("linkedList: "+linkedList);
        log.info("paramMap: "+paramMap);
    }

}

执行结果：

inkedList: [{createBy=tjt, cameraId=camera01, startTime=2019-1-10 22:58:19},{createBy=tjt, cameraId=camera02, startTime=2019-1-10 22:58:19}, {createBy=tjt, cameraId=camera03, startTime=2019-1-10 22:58:19}]
 paramMap: {camera_id_list=[{createBy=tjt, cameraId=camera01, startTime=2019-1-10 22:58:19}, {createBy=tjt, cameraId=camera02, startTime=2019-1-10 22:58:19}, {createBy=tjt, cameraId=camera03, startTime=2019-1-10 22:58:19}], callback=http://www.baidu.com}

 

方法二：

如果你的摄像头监控任务格式为：

{camera_id_list=[{cameraId=camera01, cameraId=camera02, cameraId=camera03}], callback=http://www.baidu.com}

二叉树treeMap，当传入的两个key值一样，会返回结果0，则会覆盖掉之前的cameraId，返回结果：{camera_id_list=[{cameraId=camera03}], callback=http://www.baidu.com}；

重写了treeMap中的比较方法，当比较结果返回值小于0，则排在二叉树的左边即集合倒序，当比较结果返回值大于0，则排在二叉树的右边亦不会覆盖之前的key值；

代码如下：

import java.util.Comparator;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.TreeMap;
import lombok.extern.slf4j.Slf4j;

@Slf4j
public class TreeMapUtil {
    
    public static void main(String[] args) {
        TreeMapUtil.testTreeMap("camera01,camera02,camera03");
    }
    
    @SuppressWarnings({ "unchecked", "deprecation" })
    public static void testTreeMap(String cameraStrList) {
        String[] splitCameraList = cameraStrList.split(",");
        LinkedList<Object> linkedList = new LinkedList<>();
        @SuppressWarnings({ "unchecked", "unused", "rawtypes" })
        TreeMap treeMap = new TreeMap(new Comparator() {
            @Override
            public int compare(Object o1, Object o2) {
                return 0;
            }
        });
        for(String splitCamera : splitCameraList) {
            treeMap.put("cameraId", splitCamera);
        }
        linkedList.add(treeMap);
        HashMap<Object, Object> paramMap = new HashMap<>();
        paramMap.put("camera_id_list", linkedList);
        paramMap.put("callback", "http://www.baidu.com");
        log.info("linkedList: "+linkedList);
        log.info("paramMap: "+paramMap);
    }
}

执行结果：

linkedList: [{cameraId=camera01, cameraId=camera02, cameraId=camera03}]
paramMap: {camera_id_list=[{cameraId=camera01, cameraId=camera02, cameraId=camera03}], callback=http://www.baidu.com}