diff --git a/src/main/java/xyz/zhouxy/plusone/validator/BaseValidator.java b/src/main/java/xyz/zhouxy/plusone/validator/BaseValidator.java
index ae00ac2..847a01d 100644
--- a/src/main/java/xyz/zhouxy/plusone/validator/BaseValidator.java
+++ b/src/main/java/xyz/zhouxy/plusone/validator/BaseValidator.java
@@ -13,7 +13,7 @@ public class BaseValidator<T> {
     private final List<PropertyValidator<T, ?, ?>> propertyValidators = new ArrayList<>();
 
     protected void withRule(final Predicate<T> rule, final String errorMessage) {
-        withRule(rule, () -> new InvalidInputException(errorMessage));
+        withRule(rule, () -> InvalidInputException.of(errorMessage));
     }
 
     protected <E extends RuntimeException> void withRule(Predicate<T> rule, Supplier<E> exceptionBuilder) {
diff --git a/src/main/java/xyz/zhouxy/plusone/validator/InvalidInputException.java b/src/main/java/xyz/zhouxy/plusone/validator/InvalidInputException.java
index b8066cf..90310ce 100644
--- a/src/main/java/xyz/zhouxy/plusone/validator/InvalidInputException.java
+++ b/src/main/java/xyz/zhouxy/plusone/validator/InvalidInputException.java
@@ -11,29 +11,29 @@ public class InvalidInputException extends BaseException {
 
     private static final long serialVersionUID = 7956661913360059670L;
 
-    public static final int ERROR_CODE = 4040200;
+    public static final String ERROR_CODE = "4040200";
 
-    private InvalidInputException(int code, String msg) {
+    private InvalidInputException(String code, String msg) {
         super(code, msg);
     }
 
-    private InvalidInputException(int code, Throwable cause) {
+    private InvalidInputException(String code, Throwable cause) {
         super(code, cause);
     }
 
-    private InvalidInputException(int code, String msg, Throwable cause) {
+    private InvalidInputException(String code, String msg, Throwable cause) {
         super(code, msg, cause);
     }
 
-    public InvalidInputException(String msg) {
-        this(ERROR_CODE, msg);
+    public static InvalidInputException of(String msg) {
+        return new InvalidInputException(ERROR_CODE, msg);
     }
 
-    public InvalidInputException(Throwable cause) {
-        this(ERROR_CODE, cause);
+    public static InvalidInputException of(Throwable cause) {
+        return new InvalidInputException(ERROR_CODE, cause);
     }
 
-    public InvalidInputException(String msg, Throwable cause) {
-        this(ERROR_CODE, msg, cause);
+    public static InvalidInputException of(String msg, Throwable cause) {
+        return new InvalidInputException(ERROR_CODE, msg, cause);
     }
 }
diff --git a/src/main/java/xyz/zhouxy/plusone/validator/PropertyValidator.java b/src/main/java/xyz/zhouxy/plusone/validator/PropertyValidator.java
index a0298d2..2dafff3 100644
--- a/src/main/java/xyz/zhouxy/plusone/validator/PropertyValidator.java
+++ b/src/main/java/xyz/zhouxy/plusone/validator/PropertyValidator.java
@@ -69,7 +69,7 @@ abstract class PropertyValidator<DTO, PROPERTY, THIS> {
     // ===== equals =====
 
     public THIS equalsThat(Object that) {
-        return equalsThat(that, value -> new InvalidInputException(String.format("(%s) 必须与 (%s) 相等", value, that)));
+        return equalsThat(that, value -> InvalidInputException.of(String.format("(%s) 必须与 (%s) 相等", value, that)));
     }
 
     public THIS equalsThat(Object that, String errMsg) {
@@ -143,7 +143,7 @@ abstract class PropertyValidator<DTO, PROPERTY, THIS> {
     }
 
     static <V> Function<V, InvalidInputException> convertExceptionCreator(String errMsg) {
-        return value -> new InvalidInputException(errMsg);
+        return value -> InvalidInputException.of(errMsg);
     }
 
     static <V, E extends RuntimeException> Function<V, E> convertExceptionCreator(