处理Tomcat停止时容器无法移除的线程

最新推荐文章于 2024-05-01 03:24:28 发布

原创最新推荐文章于 2024-05-01 03:24:28 发布 · 1k 阅读

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CC 4.0 BY-SA版权

本文介绍了一种在Tomcat服务器停止时清理无法正常移除的线程的方法，通过访问Thread类的私有字段，遍历所有线程并清除其ThreadLocal引用，以避免内存泄漏。

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private Integer immolate() {
       log.info("处理Tomcat停止时容器无法移除的线程...");
       int count = 0;
       try {
           final Field threadLocalsField = Thread.class
                   .getDeclaredField("threadLocals");
           threadLocalsField.setAccessible(true);
           final Field inheritableThreadLocalsField = Thread.class
                   .getDeclaredField("inheritableThreadLocals");
           inheritableThreadLocalsField.setAccessible(true);
           for (final Thread thread : Thread.getAllStackTraces().keySet()) {
               count += clear(threadLocalsField.get(thread));
               count += clear(inheritableThreadLocalsField.get(thread));
               if (thread != null) {
                   thread.setContextClassLoader(null);
               }
           }
           log.info("immolated " + count + " values in ThreadLocals");
       } catch (Exception e) {
           throw new Error("ThreadLocalImmolater.immolate()", e);
       }
       return count;
   }

   @SuppressWarnings("rawtypes")
   private int clear(final Object threadLocalMap) throws Exception {
       if (threadLocalMap == null)
           return 0;
       int count = 0;
       final Field tableField = threadLocalMap.getClass()
               .getDeclaredField("table");
       tableField.setAccessible(true);
       final Object table = tableField.get(threadLocalMap);
       for (int i = 0, length = Array.getLength(table); i < length; ++i) {
           final Object entry = Array.get(table, i);
           if (entry != null) {
               final Object threadLocal = ((WeakReference) entry).get();
               if (threadLocal != null) {
                   Array.set(table, i, null);
                   ++count;
               }
           }
       }
       return count;
   }