feat（system）：TenantUtils 增加 isTenantEnable 是否开启租户的开关

yudao-framework/yudao-spring-boot-starter-biz-tenant/src/main/java/cn/iocoder/yudao/framework/tenant/core/util/TenantUtils.java

@@ -1,9 +1,12 @@
 package cn.iocoder.yudao.framework.tenant.core.util;
 
+import cn.hutool.extra.spring.SpringUtil;
 import cn.iocoder.yudao.framework.tenant.core.context.TenantContextHolder;
+import com.google.common.base.Suppliers;
 
 import java.util.Map;
 import java.util.concurrent.Callable;
+import java.util.function.Supplier;
 
 import static cn.iocoder.yudao.framework.web.core.util.WebFrameworkUtils.HEADER_TENANT_ID;
 
@@ -14,6 +17,21 @@ import static cn.iocoder.yudao.framework.web.core.util.WebFrameworkUtils.HEADER_
  */
 public class TenantUtils {
 
+    /**
+     * 多租户开关，首次使用时读取并缓存
+     */
+    private static final Supplier<Boolean> TENANT_ENABLE = Suppliers.memoize(
+            () -> !Boolean.FALSE.equals(SpringUtil.getProperty("yudao.tenant.enable", Boolean.class, true)));
+
+    /**
+     * 判断是否开启多租户
+     *
+     * @return 是否开启多租户
+     */
+    public static boolean isTenantEnable() {
+        return TENANT_ENABLE.get();
+    }
+
     /**
      * 使用指定租户，执行对应的逻辑
      *

yudao-framework/yudao-spring-boot-starter-biz-tenant/src/test/java/cn/iocoder/yudao/framework/tenant/core/util/TenantUtilsTest.java

@@ -0,0 +1,27 @@
+package cn.iocoder.yudao.framework.tenant.core.util;
+
+import cn.hutool.extra.spring.SpringUtil;
+import org.junit.jupiter.api.Test;
+import org.mockito.MockedStatic;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mockStatic;
+import static org.mockito.Mockito.times;
+
+class TenantUtilsTest {
+
+    @Test
+    void shouldReadTenantEnableOnlyOnce() {
+        // 准备多租户开关
+        try (MockedStatic<SpringUtil> springUtil = mockStatic(SpringUtil.class)) {
+            springUtil.when(() -> SpringUtil.getProperty("yudao.tenant.enable", Boolean.class, true))
+                    .thenReturn(true);
+
+            // 多次访问只读取一次配置
+            assertTrue(TenantUtils.isTenantEnable());
+            assertTrue(TenantUtils.isTenantEnable());
+            springUtil.verify(() -> SpringUtil.getProperty("yudao.tenant.enable", Boolean.class, true), times(1));
+        }
+    }
+
+}