范例BUG修复@20210225：Spring Cache缓存使用范例的BUG修复，确保缓存的key不为null。

ipu-rest-scaffold/src/main/java/com/ai/ipu/server/control/MenuController.java

@@ -9,6 +9,7 @@ import org.springframework.web.bind.annotation.ResponseBody;
import com.ai.ipu.data.JMap;
import com.ai.ipu.data.impl.JsonMap;
import com.ai.ipu.restful.framework.SpringSessionManager;
import com.ai.ipu.server.service.MenuService;
@Controller
@@ -27,7 +28,7 @@ public class MenuController {
    public JMap takeMenu(JMap input) throws Exception {
        log.debug("获取菜单");
        /*获取账号*/
        String username = input.getString("username");
        String username = input.getString("username", SpringSessionManager.getAccount());
        String menuData = menuService.menu(username);
        JMap result = new JsonMap();
        result.put("menu",menuData);
@@ -39,7 +40,7 @@ public class MenuController {
    public JMap clearMenuCache(JMap input) throws Exception {
        log.debug("清除缓存");
        /*获取账号*/
        String username = input.getString("username");
        String username = input.getString("username", SpringSessionManager.getAccount());
        menuService.clearMenuCache(username);
        return new JsonMap();
    }
@@ -61,7 +62,7 @@ public class MenuController {
    public JMap updateMenuCache(JMap input) throws Exception {
        log.debug("更新缓存里的菜单");
        /*获取账号*/
        String username = input.getString("username");
        String username = input.getString("username", SpringSessionManager.getAccount());
        String menuData = menuService.updateMenuCache(username);
        JMap result = new JsonMap();
        result.put("menu",menuData);

ipu-rest-scaffold/src/main/java/com/ai/ipu/server/service/impl/MenuServiceImpl.java

@@ -16,7 +16,7 @@ public class MenuServiceImpl implements MenuService {
    
    private static final String MENU_DATA_CONFIG = "menu.json";
    
    //@Cacheable(value = "menu", key = "#username", condition = "{#root.target.needCache(#username)}")
    @Cacheable(value = "menu", key = "#username", condition = "{#root.target.needCache(#username)}")
    public String menu(String username) throws Exception {
        /*读取默认的菜单配置*/
        String menuJson =