Initial commit 单线程成功，并行报错

src/test/java/ThreadList.java

@@ -0,0 +1,61 @@
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.*;
+
+/**
+ * @author yjy
+ * @version 1.0
+ * @date 2021/7/30 11:09 上午
+ */
+public class ThreadList {
+
+    public static void main(String[] args) throws InterruptedException, ExecutionException {
+        List<String> list = new ArrayList<>(); //造list数据
+        for (int i = 0; i < 5300; i++) {
+            list.add("" + i);
+        }
+        // 计算线程数
+        int threadSize = 500;//每500条数据开启一个线程
+        int remainder = list.size() % threadSize;  //取余
+        int threadNum = 0; //线程数
+        if (remainder == 0) { //能整除500
+            threadNum = list.size() / threadSize;
+        } else {  //不能整除线程数要加1
+            threadNum = list.size() / threadSize + 1;
+        }
+
+        ExecutorService eService = Executors.newFixedThreadPool(threadNum); //创建一个线程池
+        List<Callable<String>> cList = new ArrayList<>();  //定义添加线程的集合
+        Callable<String> task = null;  //创建单个线程
+        List<String> sList = null;
+
+        for (int i = 0; i < threadNum; i++) {  //每个线程中加入分段数据
+
+            if (i == threadNum - 1) {
+                sList = list.subList(i * threadSize, list.size());
+            } else {
+                sList = list.subList(i * threadSize, (i + 1) * threadSize);
+            }
+
+            final List<String> nowList = sList;
+            //创建单个线程
+            task = new Callable<String>() {
+                @Override
+                public String call() throws Exception {
+                    StringBuffer sb = new StringBuffer();
+                    for (int j = 0; j < nowList.size(); j++) {
+                        sb.append("" + nowList.get(j));
+                    }
+                    return sb.toString();
+                }
+            };
+            cList.add(task); //添加线程
+        }
+        List<Future<String>> results = eService.invokeAll(cList); //执行所有创建的线程，并获取返回值（会把所有线程的返回值都返回）
+
+        for (Future<String> str : results) {  //打印返回值
+            System.out.println(str.get());
+        }
+        eService.shutdown();
+    }
+}