!467 新增 ThreadLocalHolder 整合 SaHolder，ThreadLocal

* fix 修复 issue#I8RWB5 字段缺少问题 ;
* add 新增 ThreadLocalHolder 替换 SaHolder ;

ruoyi-common/ruoyi-common-core/src/main/java/org/dromara/common/core/context/ThreadLocalHolder.java

@@ -0,0 +1,57 @@
+package org.dromara.common.core.context;
+
+import com.alibaba.ttl.TransmittableThreadLocal;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * 线程持有类
+ *
+ * @author Michelle.Chung
+ */
+public class ThreadLocalHolder {
+
+    /**
+     * 初始化 (支持异步)
+     */
+    private static final ThreadLocal<Map<String, Object>> THREAD_LOCAL = TransmittableThreadLocal.withInitial(HashMap::new);
+
+    /**
+     * 设置值
+     *
+     * @param key 键
+     * @param value 值
+     */
+    public static <T> void set(String key, T value) {
+        THREAD_LOCAL.get().put(key, value);
+    }
+
+    /**
+     * 获取值
+     *
+     * @param key 键
+     * @return 值
+     */
+    @SuppressWarnings("unchecked")
+    public static <T> T get(String key) {
+        return (T) THREAD_LOCAL.get().get(key);
+    }
+
+    /**
+     * 移除值
+     *
+     * @param key 键
+     */
+    public static void remove(String key) {
+        THREAD_LOCAL.get().remove(key);
+    }
+
+    /**
+     * 清空值
+     */
+    public static void clear() {
+        THREAD_LOCAL.remove();
+    }
+
+}