diff --git a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/BaseValidator.java b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/BaseValidator.java
index 1be9907..33e3643 100644
--- a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/BaseValidator.java
+++ b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/BaseValidator.java
@@ -24,6 +24,8 @@ import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
+import xyz.zhouxy.plusone.validator.function.*;
+
 /**
  * BaseValidator
  *
@@ -79,30 +81,60 @@ public abstract class BaseValidator<T> {
         return validator;
     }
 
+    protected final IntPropertyValidator<T> ruleFor(ToIntegerFunction<T> getter) {
+        IntPropertyValidator<T> validator = new IntPropertyValidator<>(getter);
+        this.rules.add(validator::validate);
+        return validator;
+    }
+
     protected final LongPropertyValidator<T> ruleForLong(Function<T, Long> getter) {
         LongPropertyValidator<T> validator = new LongPropertyValidator<>(getter);
         this.rules.add(validator::validate);
         return validator;
     }
 
+    protected final LongPropertyValidator<T> ruleFor(ToLongObjectFunction<T> getter) {
+        LongPropertyValidator<T> validator = new LongPropertyValidator<>(getter);
+        this.rules.add(validator::validate);
+        return validator;
+    }
+
     protected final DoublePropertyValidator<T> ruleForDouble(Function<T, Double> getter) {
         DoublePropertyValidator<T> validator = new DoublePropertyValidator<>(getter);
         this.rules.add(validator::validate);
         return validator;
     }
 
+    protected final DoublePropertyValidator<T> ruleFor(ToDoubleObjectFunction<T> getter) {
+        DoublePropertyValidator<T> validator = new DoublePropertyValidator<>(getter);
+        this.rules.add(validator::validate);
+        return validator;
+    }
+
     protected final BoolPropertyValidator<T> ruleForBool(Function<T, Boolean> getter) {
         BoolPropertyValidator<T> validator = new BoolPropertyValidator<>(getter);
         this.rules.add(validator::validate);
         return validator;
     }
 
+    protected final BoolPropertyValidator<T> ruleFor(ToBoolObjectFunction<T> getter) {
+        BoolPropertyValidator<T> validator = new BoolPropertyValidator<>(getter);
+        this.rules.add(validator::validate);
+        return validator;
+    }
+
     protected final StringPropertyValidator<T> ruleForString(Function<T, String> getter) {
         StringPropertyValidator<T> validator = new StringPropertyValidator<>(getter);
         this.rules.add(validator::validate);
         return validator;
     }
 
+    protected final StringPropertyValidator<T> ruleFor(ToStringFunction<T> getter) {
+        StringPropertyValidator<T> validator = new StringPropertyValidator<>(getter);
+        this.rules.add(validator::validate);
+        return validator;
+    }
+
     protected final <E> CollectionPropertyValidator<T, E> ruleForCollection(Function<T, Collection<E>> getter) {
         CollectionPropertyValidator<T, E> validator = new CollectionPropertyValidator<>(getter);
         this.rules.add(validator::validate);
diff --git a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/MapValidator.java b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/MapValidator.java
index e724bf2..c678ff7 100644
--- a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/MapValidator.java
+++ b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/MapValidator.java
@@ -60,7 +60,8 @@ public abstract class MapValidator<K, V> extends BaseValidator<Map<K, V>> {
     // ========== ruleFor ==========
 
     protected final ObjectPropertyValidator<Map<K, V>, V> ruleFor(K key) {
-        return ruleFor(m -> m.get(key));
+        final Function<Map<K, V>, V> func = m -> m.get(key);
+        return ruleFor(func);
     }
 
     protected final IntPropertyValidator<Map<K, V>> ruleForInt(K key) {
diff --git a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToBoolObjectFunction.java b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToBoolObjectFunction.java
new file mode 100644
index 0000000..f5e40c7
--- /dev/null
+++ b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToBoolObjectFunction.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package xyz.zhouxy.plusone.validator.function;
+
+import java.io.Serializable;
+import java.util.function.Function;
+
+@FunctionalInterface
+public interface ToBoolObjectFunction<T> extends Function<T, Boolean>, Serializable {
+}
diff --git a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToDoubleObjectFunction.java b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToDoubleObjectFunction.java
new file mode 100644
index 0000000..318e903
--- /dev/null
+++ b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToDoubleObjectFunction.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package xyz.zhouxy.plusone.validator.function;
+
+import java.io.Serializable;
+import java.util.function.Function;
+
+@FunctionalInterface
+public interface ToDoubleObjectFunction<T> extends Function<T, Double>, Serializable {
+}
diff --git a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToIntegerFunction.java b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToIntegerFunction.java
new file mode 100644
index 0000000..8b6c7f6
--- /dev/null
+++ b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToIntegerFunction.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package xyz.zhouxy.plusone.validator.function;
+
+import java.io.Serializable;
+import java.util.function.Function;
+
+@FunctionalInterface
+public interface ToIntegerFunction<T> extends Function<T, Integer>, Serializable {
+}
diff --git a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToLongObjectFunction.java b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToLongObjectFunction.java
new file mode 100644
index 0000000..3965286
--- /dev/null
+++ b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToLongObjectFunction.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package xyz.zhouxy.plusone.validator.function;
+
+import java.io.Serializable;
+import java.util.function.Function;
+
+@FunctionalInterface
+public interface ToLongObjectFunction<T> extends Function<T, Long>, Serializable {
+}
diff --git a/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToStringFunction.java b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToStringFunction.java
new file mode 100644
index 0000000..ba5a37c
--- /dev/null
+++ b/plusone-validator/src/main/java/xyz/zhouxy/plusone/validator/function/ToStringFunction.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package xyz.zhouxy.plusone.validator.function;
+
+import java.io.Serializable;
+import java.util.function.Function;
+
+@FunctionalInterface
+public interface ToStringFunction<T> extends Function<T, String>, Serializable {
+}