java中多个线程同一把锁，能用实时拼接的string对象做锁对象吗

设计思路： 1. 定义一个实体类，包含4个属性id、param、no、num； 2. 定义一个缓存类，用于存储未完整拼接的数据； 3. 定义一个拼接类，用于拼接完整数据并排序； 4. 定义多线程类，用于处理数据拼接业务。 代码实现： 1. 实体类 ``` public class Data { private String id; private String param; private int no; private int num; public Data(String id, String param, int no, int num) { this.id = id; this.param = param; this.no = no; this.num = num; } // getter and setter } ``` 2. 缓存类 ``` public class Cache { private Map<String, List<Data>> cacheMap = new ConcurrentHashMap<>(); public void addData(Data data) { if (cacheMap.containsKey(data.getId())) { List<Data> dataList = cacheMap.get(data.getId()); int size = dataList.size(); if (size < data.getNum()) { dataList.add(data); } else if (size == data.getNum()) { dataList.add(data); Collections.sort(dataList, Comparator.comparingInt(Data::getNo)); StringBuilder sb = new StringBuilder(); for (Data d : dataList) { sb.append(d.getParam()); } System.out.println("完整数据：" + sb.toString()); cacheMap.remove(data.getId()); } } else { List<Data> dataList = new ArrayList<>(); dataList.add(data); cacheMap.put(data.getId(), dataList); } } } ``` 3. 拼接类 ``` public class Joiner { public static String joinData(List<Data> dataList) { Collections.sort(dataList, Comparator.comparingInt(Data::getNo)); StringBuilder sb = new StringBuilder(); for (Data d : dataList) { sb.append(d.getParam()); } return sb.toString(); } } ``` 4. 多线程类 ``` public class MultiThreadJoiner implements Runnable { private Data data; private Cache cache; public MultiThreadJoiner(Data data, Cache cache) { this.data = data; this.cache = cache; } @Override public void run() { cache.addData(data); } } ``` 测试代码： ``` public static void main(String[] args) { Cache cache = new Cache(); // 模拟数据 Data data1 = new Data("1", "a", 1, 2); Data data2 = new Data("1", "b", 2, 2); Data data3 = new Data("2", "c", 1, 3); Data data4 = new Data("2", "d", 2, 3); Data data5 = new Data("2", "e", 3, 3); Data data6 = new Data("3", "f", 1, 1); // 多线程处理数据拼接 Thread t1 = new Thread(new MultiThreadJoiner(data1, cache)); Thread t2 = new Thread(new MultiThreadJoiner(data2, cache)); Thread t3 = new Thread(new MultiThreadJoiner(data3, cache)); Thread t4 = new Thread(new MultiThreadJoiner(data4, cache)); Thread t5 = new Thread(new MultiThreadJoiner(data5, cache)); Thread t6 = new Thread(new MultiThreadJoiner(data6, cache)); t1.start(); t2.start(); t3.start(); t4.start(); t5.start(); t6.start(); } ```

设计思路： 1. 维护一个 Map，key 为 id，value 为 List，用于存储同一个 id 对应的多条数据。 2. 在存储数据时，判断 Map 中是否已经存在该 id 对应的 List，如果不存在则新建一个 List，并将数据存入；如果存在则将数据添加到对应的 List 中。 3. 在每次存储数据后，判断该 id 对应的 List 中数据的数量是否等于 num，如果等于则将 List 中的数据按照 no 进行排序，然后将 param 拼接起来。 4. 如果数量不足 num，则将 List 存入缓存，等待后续的数据到达。 5. 可以使用多线程进行数据的处理，每个线程负责从缓存中取出数据进行处理。 代码实现： ```java import java.util.ArrayList; import java.util.Collections; import java.util.HashMap; import java.util.List; import java.util.Map; public class DataJoiner { private Map<String, List<Data>> dataMap = new HashMap<>(); // 存储数据的 Map private Map<String, List<Data>> cacheMap = new HashMap<>(); // 存储未完成的数据的 Map private int num; // 每个 id 对应的数据数量 public DataJoiner(int num) { this.num = num; } public synchronized void addData(Data newData) { String id = newData.getId(); List<Data> dataList = dataMap.get(id); if (dataList == null) { dataList = new ArrayList<>(); dataMap.put(id, dataList); } dataList.add(newData); if (dataList.size() == num) { // 数据数量达到要求，进行拼接 Collections.sort(dataList); StringBuilder sb = new StringBuilder(); for (Data data : dataList) { sb.append(data.getParam()); } System.out.println(sb.toString()); dataMap.remove(id); } else if (dataList.size() < num) { // 数据数量不足，放入缓存 List<Data> cacheList = cacheMap.get(id); if (cacheList == null) { cacheList = new ArrayList<>(); cacheMap.put(id, cacheList); } cacheList.add(newData); } else { // 数据数量超过要求，清空数据并输出错误信息 dataMap.remove(id); System.out.println("Error: id " + id + " contains too many data."); } } public synchronized void processCache() { for (Map.Entry<String, List<Data>> entry : cacheMap.entrySet()) { String id = entry.getKey(); List<Data> dataList = dataMap.get(id); if (dataList == null) { dataList = new ArrayList<>(); dataMap.put(id, dataList); } dataList.addAll(entry.getValue()); if (dataList.size() == num) { // 数据数量达到要求，进行拼接 Collections.sort(dataList); StringBuilder sb = new StringBuilder(); for (Data data : dataList) { sb.append(data.getParam()); } System.out.println(sb.toString()); dataMap.remove(id); } } cacheMap.clear(); } public static void main(String[] args) { DataJoiner joiner = new DataJoiner(3); // 每个 id 对应的数据数量为 3 joiner.addData(new Data("1", "aaa", 1, 3)); joiner.addData(new Data("2", "bbb", 1, 3)); joiner.addData(new Data("1", "ccc", 2, 3)); joiner.addData(new Data("3", "ddd", 1, 2)); joiner.addData(new Data("2", "eee", 2, 3)); joiner.addData(new Data("1", "fff", 3, 3)); joiner.processCache(); } private static class Data implements Comparable<Data> { private String id; private String param; private int no; private int num; public Data(String id, String param, int no, int num) { this.id = id; this.param = param; this.no = no; this.num = num; } public String getId() { return id; } public String getParam() { return param; } public int getNo() { return no; } public int getNum() { return num; } @Override public int compareTo(Data o) { return Integer.compare(no, o.no); } } } ``` 注：以上代码仅作为实现的示例，实际业务场景中可能需要进行更多的异常处理和线程安全保障。