src/main/java/ru/ulstu/conference/controller/ConferenceController.java

@@ -74,12 +74,9 @@ public class ConferenceController {
 
     @PostMapping(value = "/conference", params = "save")
     public String save(@Valid ConferenceDto conferenceDto, Errors errors) throws IOException {
-        conferenceService.filterEmptyDeadlines(conferenceDto);
+        if (!conferenceService.save(conferenceDto, errors)) {
-        conferenceService.checkEmptyFieldsOfDeadline(conferenceDto, errors);
-        if (errors.hasErrors()) {
             return CONFERENCE_PAGE;
         }
-        conferenceService.save(conferenceDto);
         return String.format(REDIRECT_TO, CONFERENCES_PAGE);
     }
 

src/main/java/ru/ulstu/conference/model/ConferenceDto.java

@@ -5,6 +5,7 @@ import com.fasterxml.jackson.annotation.JsonProperty;
 import org.hibernate.validator.constraints.NotEmpty;
 import org.springframework.format.annotation.DateTimeFormat;
 import ru.ulstu.deadline.model.Deadline;
+import ru.ulstu.name.NameContainer;
 import ru.ulstu.paper.model.Paper;
 
 import javax.persistence.Temporal;
@@ -16,7 +17,7 @@ import java.util.List;
 
 import static ru.ulstu.core.util.StreamApiUtils.convert;
 
-public class ConferenceDto {
+public class ConferenceDto extends NameContainer {
 
     private final static String BEGIN_DATE = "Начало: ";
     private final static String END_DATE = "Конец: ";

src/main/java/ru/ulstu/conference/repository/ConferenceRepository.java

@@ -5,12 +5,13 @@ import org.springframework.data.jpa.repository.Modifying;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.query.Param;
 import ru.ulstu.conference.model.Conference;
+import ru.ulstu.name.BaseRepository;
 import ru.ulstu.user.model.User;
 
 import java.util.Date;
 import java.util.List;
 
-public interface ConferenceRepository extends JpaRepository<Conference, Integer> {
+public interface ConferenceRepository extends JpaRepository<Conference, Integer>, BaseRepository {
     @Query("SELECT c FROM Conference c LEFT JOIN c.users u WHERE (:user IS NULL OR u.user = :user) " +
             "AND (YEAR(c.beginDate) = :year OR :year IS NULL) ORDER BY begin_date DESC")
     List<Conference> findByUserAndYear(@Param("user") User user, @Param("year") Integer year);
@@ -24,4 +25,8 @@ public interface ConferenceRepository extends JpaRepository<Conference, Integer>
     @Modifying
     @Query("UPDATE Conference c SET c.ping = (c.ping + 1) WHERE c.id = :id")
     int updatePingConference(@Param("id") Integer id);
+
+    @Override
+    @Query("SELECT title FROM Conference c WHERE (c.title = :name) AND (:id IS NULL OR c.id != :id) ")
+    String findByNameAndNotId(@Param("name") String name, @Param("id") Integer id);
 }

src/main/java/ru/ulstu/conference/service/ConferenceService.java

@@ -13,6 +13,7 @@ import ru.ulstu.conference.model.ConferenceUser;
 import ru.ulstu.conference.repository.ConferenceRepository;
 import ru.ulstu.deadline.model.Deadline;
 import ru.ulstu.deadline.service.DeadlineService;
+import ru.ulstu.name.BaseService;
 import ru.ulstu.paper.model.Paper;
 import ru.ulstu.paper.service.PaperService;
 import ru.ulstu.ping.service.PingService;
@@ -31,7 +32,7 @@ import static org.springframework.util.ObjectUtils.isEmpty;
 import static ru.ulstu.core.util.StreamApiUtils.convert;
 
 @Service
-public class ConferenceService {
+public class ConferenceService extends BaseService {
     private final static int MAX_DISPLAY_SIZE = 40;
 
     private final ConferenceRepository conferenceRepository;
@@ -51,6 +52,7 @@ public class ConferenceService {
                              PingService pingService,
                              ConferenceNotificationService conferenceNotificationService,
                              EventService eventService) {
+        this.baseRepository = conferenceRepository;
         this.conferenceRepository = conferenceRepository;
         this.conferenceUserService = conferenceUserService;
         this.deadlineService = deadlineService;
@@ -89,12 +91,26 @@ public class ConferenceService {
         return new ConferenceDto(conferenceRepository.findOne(id));
     }
 
-    public void save(ConferenceDto conferenceDto) throws IOException {
+    public boolean save(ConferenceDto conferenceDto, Errors errors) throws IOException {
+        conferenceDto.setName(conferenceDto.getTitle());
+        filterEmptyDeadlines(conferenceDto);
+        checkEmptyFieldsOfDeadline(conferenceDto, errors);
+        checkUniqueName(conferenceDto,
+                errors,
+                conferenceDto.getId(),
+                "title",
+                "Конференция с таким именем уже существует");
+        if (errors.hasErrors()) {
+            return false;
+        }
+
         if (isEmpty(conferenceDto.getId())) {
             create(conferenceDto);
         } else {
             update(conferenceDto);
         }
+
+        return true;
     }
 
     @Transactional
@@ -280,7 +296,6 @@ public class ConferenceService {
         }
     }
 
-
     public void filterEmptyDeadlines(ConferenceDto conferenceDto) {
         conferenceDto.setDeadlines(conferenceDto.getDeadlines().stream()
                 .filter(dto -> dto.getDate() != null || !org.springframework.util.StringUtils.isEmpty(dto.getDescription()))

src/main/java/ru/ulstu/name/BaseRepository.java

@@ -0,0 +1,7 @@
+package ru.ulstu.name;
+
+import org.springframework.data.repository.query.Param;
+
+public interface BaseRepository {
+    String findByNameAndNotId(@Param("name") String name, @Param("id") Integer id);
+}

src/main/java/ru/ulstu/name/BaseService.java

@@ -0,0 +1,16 @@
+package ru.ulstu.name;
+
+import org.springframework.stereotype.Service;
+import org.springframework.validation.Errors;
+
+@Service
+public abstract class BaseService {
+
+    public BaseRepository baseRepository;
+
+    public void checkUniqueName(NameContainer nameContainer, Errors errors, Integer id, String checkField, String errorMessage) {
+        if (nameContainer.getName().equals(baseRepository.findByNameAndNotId(nameContainer.getName(), id))) {
+            errors.rejectValue(checkField, "errorCode", errorMessage);
+        }
+    }
+}

src/main/java/ru/ulstu/name/NameContainer.java

@@ -0,0 +1,14 @@
+package ru.ulstu.name;
+
+public abstract class NameContainer {
+
+    private String name = "";
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

src/main/resources/templates/conferences/conference.html

@@ -30,11 +30,12 @@
                                     <label for="title">Название:</label>
                                     <input class="form-control" th:field="*{title}" id="title" type="text"
                                            placeholder="Название конференции"/>
-                                    <p th:if="${#fields.hasErrors('title')}" th:errors="*{title}"
-                                       class="alert alert-danger">Incorrect title</p>
-                                    <p class="help-block text-danger"></p>
                                 </div>
 
+                                <p th:if="${#fields.hasErrors('title')}" th:errors="*{title}"
+                                   class="alert alert-danger">Incorrect title</p>
+                                <p class="help-block text-danger"></p>
+
                                 <div class="form-group">
                                     <label for="url">URL:</label>
                                     <input class="form-control" th:field="*{url}" id="url" type="text"