diff --git a/plusone-basic/plusone-basic-domain/src/main/java/xyz/zhouxy/plusone/domain/ValidatableStringRecord.java b/plusone-basic/plusone-basic-domain/src/main/java/xyz/zhouxy/plusone/domain/ValidatableStringRecord.java
deleted file mode 100644
index 0a03e65..0000000
--- a/plusone-basic/plusone-basic-domain/src/main/java/xyz/zhouxy/plusone/domain/ValidatableStringRecord.java
+++ /dev/null
@@ -1,41 +0,0 @@
-package xyz.zhouxy.plusone.domain;
-
-import java.util.Optional;
-import java.util.regex.Pattern;
-
-import com.fasterxml.jackson.annotation.JsonIgnore;
-import com.fasterxml.jackson.annotation.JsonValue;
-
-/**
- * 带校验的字符串值对象
- *
- * @author <a href="https://gitee.com/zhouxy108">ZhouXY</a>
- */
-public abstract class ValidatableStringRecord implements IValueObject {
-
-    protected String value;
-    protected final Pattern format;
-
-    protected ValidatableStringRecord(Pattern format) {
-        this.format = format;
-    }
-
-    @JsonIgnore
-    protected boolean isValid() {
-        return format.matcher(value).matches();
-    }
-
-    @JsonValue
-    public String value() {
-        return value;
-    }
-
-    @Override
-    public String toString() {
-        return value;
-    }
-
-    public static String getValueOrNull(Optional<? extends ValidatableStringRecord> s) {
-        return s.isPresent() ? s.get().value() : null;
-    }
-}
diff --git a/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Email.java b/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Email.java
index 680e881..15fbf58 100644
--- a/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Email.java
+++ b/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Email.java
@@ -3,8 +3,11 @@ package xyz.zhouxy.plusone.system.domain.model.account;
 import java.util.Objects;
 import java.util.regex.Pattern;
 
+import javax.annotation.Nullable;
+
 import cn.hutool.core.util.DesensitizedUtil;
 import xyz.zhouxy.plusone.commons.annotation.StaticFactoryMethod;
+import xyz.zhouxy.plusone.commons.annotation.ValueObject;
 import xyz.zhouxy.plusone.commons.constant.PatternConsts;
 
 /**
@@ -12,19 +15,13 @@ import xyz.zhouxy.plusone.commons.constant.PatternConsts;
  *
  * @author <a href="https://gitee.com/zhouxy108">ZhouXY</a>
  */
-public class Email extends Principal {
+@ValueObject
+public final class Email extends Principal {
 
     public static final Pattern REGEX = PatternConsts.EMAIL;
 
     private Email(String email) {
-        super(REGEX);
-        if (email == null) {
-            throw new IllegalArgumentException("邮箱地址不能为空");
-        }
-        this.value = email;
-        if (!isValid()) {
-            throw new IllegalArgumentException("邮箱地址格式错误");
-        }
+        super(email, REGEX);
     }
 
     @StaticFactoryMethod(Email.class)
@@ -33,19 +30,13 @@ public class Email extends Principal {
     }
 
     @StaticFactoryMethod(Email.class)
+    @Nullable
     public static Email ofNullable(String email) {
         return Objects.nonNull(email) ? new Email(email) : null;
     }
 
-    /**
-     * 脱敏后的数据
-     */
-    public String safeValue() {
-        return DesensitizedUtil.email(this.value);
-    }
-
     @Override
-    public String toString() {
-        return this.safeValue();
+    public String safeValue() {
+        return DesensitizedUtil.email(value());
     }
 }
diff --git a/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/MobilePhone.java b/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/MobilePhone.java
index 15a3692..0542611 100644
--- a/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/MobilePhone.java
+++ b/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/MobilePhone.java
@@ -3,8 +3,11 @@ package xyz.zhouxy.plusone.system.domain.model.account;
 import java.util.Objects;
 import java.util.regex.Pattern;
 
+import javax.annotation.Nullable;
+
 import cn.hutool.core.util.DesensitizedUtil;
 import xyz.zhouxy.plusone.commons.annotation.StaticFactoryMethod;
+import xyz.zhouxy.plusone.commons.annotation.ValueObject;
 import xyz.zhouxy.plusone.commons.constant.PatternConsts;
 
 /**
@@ -12,19 +15,13 @@ import xyz.zhouxy.plusone.commons.constant.PatternConsts;
  *
  * @author <a href="https://gitee.com/zhouxy108">ZhouXY</a>
  */
+@ValueObject
 public class MobilePhone extends Principal {
 
     public static final Pattern REGEX = PatternConsts.MOBILE_PHONE;
 
     private MobilePhone(String mobilePhone) {
-        super(REGEX);
-        if (mobilePhone == null) {
-            throw new IllegalArgumentException("手机号不能为空");
-        }
-        this.value = mobilePhone;
-        if (!isValid()) {
-            throw new IllegalArgumentException("手机号格式错误");
-        }
+        super(mobilePhone, REGEX);
     }
 
     @StaticFactoryMethod(MobilePhone.class)
@@ -33,16 +30,13 @@ public class MobilePhone extends Principal {
     }
 
     @StaticFactoryMethod(MobilePhone.class)
+    @Nullable
     public static MobilePhone ofNullable(String mobilePhone) {
         return Objects.nonNull(mobilePhone) ? new MobilePhone(mobilePhone) : null;
     }
 
-    public String safeValue() {
-        return DesensitizedUtil.mobilePhone(this.value);
-    }
-
     @Override
-    public String toString() {
-        return this.safeValue();
+    public String safeValue() {
+        return DesensitizedUtil.mobilePhone(this.value());
     }
 }
diff --git a/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Nickname.java b/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Nickname.java
index d1964b2..e268aa0 100644
--- a/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Nickname.java
+++ b/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Nickname.java
@@ -4,27 +4,22 @@ import java.util.Objects;
 import java.util.regex.Pattern;
 
 import xyz.zhouxy.plusone.commons.annotation.StaticFactoryMethod;
+import xyz.zhouxy.plusone.commons.annotation.ValueObject;
 import xyz.zhouxy.plusone.commons.constant.PatternConsts;
-import xyz.zhouxy.plusone.domain.ValidatableStringRecord;
+import xyz.zhouxy.plusone.commons.domain.ValidatableStringRecord;
 
 /**
  * 值对象：昵称
  *
  * @author <a href="https://gitee.com/zhouxy108">ZhouXY</a>
  */
+@ValueObject
 public class Nickname extends ValidatableStringRecord {
 
     public static final Pattern REGEX = PatternConsts.NICKNAME;
 
     private Nickname(String value) {
-        super(REGEX);
-        if (value == null) {
-            throw new IllegalArgumentException("昵称不能为空");
-        }
-        this.value = value;
-        if (!isValid()) {
-            throw new IllegalArgumentException("昵称格式错误");
-        }
+        super(value, REGEX);
     }
 
     @StaticFactoryMethod(Nickname.class)
diff --git a/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Principal.java b/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Principal.java
index c4a4701..4cf0463 100644
--- a/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Principal.java
+++ b/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Principal.java
@@ -2,15 +2,23 @@ package xyz.zhouxy.plusone.system.domain.model.account;
 
 import java.util.regex.Pattern;
 
-import xyz.zhouxy.plusone.domain.ValidatableStringRecord;
+import xyz.zhouxy.plusone.commons.domain.ValidatableStringRecord;
+import xyz.zhouxy.plusone.domain.IValueObject;
 
 /**
  * 账号标识符
  *
  * @author <a href="https://gitee.com/zhouxy108">ZhouXY</a>
  */
-public abstract class Principal extends ValidatableStringRecord {
-    protected Principal(Pattern format) {
-        super(format);
+public abstract class Principal extends ValidatableStringRecord implements IValueObject {
+    protected Principal(String principal, Pattern pattern) {
+        super(principal, pattern);
+    }
+
+    protected abstract String safeValue();
+
+    @Override
+    public final String toString() {
+        return this.safeValue();
     }
 }
diff --git a/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Username.java b/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Username.java
index 92b1420..25446b1 100644
--- a/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Username.java
+++ b/plusone-system/plusone-system-domain/src/main/java/xyz/zhouxy/plusone/system/domain/model/account/Username.java
@@ -3,6 +3,7 @@ package xyz.zhouxy.plusone.system.domain.model.account;
 import java.util.regex.Pattern;
 
 import xyz.zhouxy.plusone.commons.annotation.StaticFactoryMethod;
+import xyz.zhouxy.plusone.commons.annotation.ValueObject;
 import xyz.zhouxy.plusone.commons.constant.PatternConsts;
 
 /**
@@ -10,23 +11,23 @@ import xyz.zhouxy.plusone.commons.constant.PatternConsts;
  *
  * @author <a href="https://gitee.com/zhouxy108">ZhouXY</a>
  */
+@ValueObject
 public class Username extends Principal {
 
     public static final Pattern REGEX = PatternConsts.USERNAME;
 
     private Username(String username) {
-        super(REGEX);
-        if (username == null) {
-            throw new IllegalArgumentException("用户名不能为空");
-        }
-        this.value = username;
-        if (!isValid()) {
-            throw new IllegalArgumentException("用户名格式错误");
-        }
+        super(username, REGEX);
     }
 
     @StaticFactoryMethod(Username.class)
     public static Username of(String username) {
         return new Username(username);
     }
+
+    @Override
+    protected String safeValue() {
+        // 不需要脱敏。
+        return value();
+    }
 }