使用 hashMap和treeMap開啟多個攝像頭的監控任務

背景：今天有個需求，傳入多個攝像頭ID，然後調用介面，開啟這些攝像頭的監控任務。

方法一：

如果你的攝像頭監控任務格式為：

{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}

這種格式的話，那麼可以用hashMap搞定。

代碼如下：

 1 import java.util.Date;
 2 import java.util.HashMap;
 3 import java.util.LinkedList;
 4 
 5 import org.apache.commons.lang.time.DateFormatUtils;
 6 
 7 import lombok.extern.slf4j.Slf4j;
 8 
 9 @Slf4j
10 public class HashMapUtil {
11     
12     public static void main(String[] args) {
13         HashMapUtil.testHashMap("camera01,camera02,camera03");
14     }
15     
16     public static void testHashMap(String cameraStrList) {
17         String[] splitCameraList = cameraStrList.split(",");
18         HashMap<String, Object> hashMap = new HashMap<>();
19         //add and delete faster than arrayList when using linkList
20         LinkedList<Object> linkedList = new LinkedList<>();
21         for(String splitCamera : splitCameraList) {
22             hashMap.put("cameraId", splitCamera);
23             hashMap.put("createBy","tjt");
24             hashMap.put("startTime", DateFormatUtils.format(new Date(), "yyyy-MM-dd HH:mm:ss"));
25             linkedList.add(hashMap);
26             hashMap = new HashMap<>();
27         }
28         HashMap<Object, Object> paramMap = new HashMap<>();
29         paramMap.put("camera_id_list", linkedList);
30         paramMap.put("callback", "http://www.baidu.com");
31         log.info("linkedList: "+linkedList);
32         log.info("paramMap: "+paramMap);
33     }
34 
35 }

執行結果：

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：

如果你的攝像頭監控任務格式為：

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

二叉樹treeMap，當傳入的兩個key值一樣，會返回結果0，則會覆蓋掉之前的cameraId，返回結果：{camera_id_list=[{cameraId=camera03}], callback=http://www.baidu.com}；

重寫了treeMap中的比較方法，當比較結果返回值小於0，則排在二叉樹的左邊即集合倒序，當比較結果返回值大於0，則排在二叉樹的右邊亦不會覆蓋之前的key值；

代碼如下：

 1 import java.util.Comparator;
 2 import java.util.HashMap;
 3 import java.util.LinkedList;
 4 import java.util.TreeMap;
 5 import lombok.extern.slf4j.Slf4j;
 6 
 7 @Slf4j
 8 public class TreeMapUtil {
 9     
10     public static void main(String[] args) {
11         TreeMapUtil.testTreeMap("camera01,camera02,camera03");
12     }
13     
14     @SuppressWarnings({ "unchecked", "deprecation" })
15     public static void testTreeMap(String cameraStrList) {
16         String[] splitCameraList = cameraStrList.split(",");
17         LinkedList<Object> linkedList = new LinkedList<>();
18         @SuppressWarnings({ "unchecked", "unused", "rawtypes" })
19         TreeMap treeMap = new TreeMap(new Comparator() {
20             @Override
21             public int compare(Object o1, Object o2) {
22                 return 0;
23             }
24         });
25         for(String splitCamera : splitCameraList) {
26             treeMap.put("cameraId", splitCamera);
27         }
28         linkedList.add(treeMap);
29         HashMap<Object, Object> paramMap = new HashMap<>();
30         paramMap.put("camera_id_list", linkedList);
31         paramMap.put("callback", "http://www.baidu.com");
32         log.info("linkedList: "+linkedList);
33         log.info("paramMap: "+paramMap);
34     }
35 }

執行結果：

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