Custom validation

src/main/java/org/sadtech/example/springvalidation/dto/PersonDto.java

@@ -2,6 +2,7 @@ package org.sadtech.example.springvalidation.dto;
 
 import lombok.Getter;
 import lombok.Setter;
+import org.sadtech.example.springvalidation.valid.CapitalLetter;
 
 import javax.persistence.Column;
 import javax.persistence.Entity;
@@ -26,6 +27,7 @@ public class PersonDto {
     private Long id;
 
     @NotBlank
+    @CapitalLetter
     private String name;
 
     @Min(1)

src/main/java/org/sadtech/example/springvalidation/valid/CapitalLetter.java

@@ -0,0 +1,24 @@
+package org.sadtech.example.springvalidation.valid;
+
+import javax.validation.Constraint;
+import javax.validation.Payload;
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+@Target({FIELD})
+@Retention(RUNTIME)
+@Constraint(validatedBy = CapitalLetterValidator.class)
+@Documented
+public @interface CapitalLetter {
+
+    String message() default "должно быть с большой буквы";
+
+    Class<?>[] groups() default {};
+
+    Class<? extends Payload>[] payload() default {};
+
+}

src/main/java/org/sadtech/example/springvalidation/valid/CapitalLetterValidator.java

@@ -0,0 +1,16 @@
+package org.sadtech.example.springvalidation.valid;
+
+import javax.validation.ConstraintValidator;
+import javax.validation.ConstraintValidatorContext;
+
+public class CapitalLetterValidator implements ConstraintValidator<CapitalLetter, String> {
+
+    @Override
+    public boolean isValid(String value, ConstraintValidatorContext context) {
+        if (value != null && !value.isEmpty()) {
+            return Character.isUpperCase(value.charAt(0));
+        }
+        return true;
+    }
+
+}