Хоть мне это не нравилось, но я сделал

data.trace.db

@@ -11810,3 +11810,50 @@ Database is already closed (to disable automatic closing at VM shutdown, add ";D
 	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
 	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
 	at java.base/java.lang.Thread.run(Thread.java:833)
+2023-05-14 10:12:20 database: flush
+org.h2.message.DbException: Внутренняя ошибка: "org.h2.mvstore.MVStoreException: The file is locked: C:/Users/Admin/Downloads/IP/IP/data.mv.db [2.1.210/7]"
+General error: "org.h2.mvstore.MVStoreException: The file is locked: C:/Users/Admin/Downloads/IP/IP/data.mv.db [2.1.210/7]" [50000-210]
+	at org.h2.message.DbException.get(DbException.java:216)
+	at org.h2.message.DbException.convert(DbException.java:414)
+	at org.h2.mvstore.db.Store.lambda$new$0(Store.java:120)
+	at org.h2.mvstore.MVStore.handleException(MVStore.java:3296)
+	at org.h2.mvstore.MVStore.panic(MVStore.java:585)
+	at org.h2.mvstore.MVStore.<init>(MVStore.java:461)
+	at org.h2.mvstore.MVStore$Builder.open(MVStore.java:4056)
+	at org.h2.mvstore.db.Store.<init>(Store.java:129)
+	at org.h2.engine.Database.<init>(Database.java:324)
+	at org.h2.engine.Engine.openSession(Engine.java:92)
+	at org.h2.engine.Engine.openSession(Engine.java:222)
+	at org.h2.engine.Engine.createSession(Engine.java:201)
+	at org.h2.engine.SessionRemote.connectEmbeddedOrServer(SessionRemote.java:338)
+	at org.h2.jdbc.JdbcConnection.<init>(JdbcConnection.java:122)
+	at org.h2.Driver.connect(Driver.java:59)
+	at com.intellij.database.remote.jdbc.helpers.JdbcHelperImpl.connect(JdbcHelperImpl.java:670)
+	at com.intellij.database.remote.jdbc.impl.RemoteDriverImpl.connect(RemoteDriverImpl.java:64)
+	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
+	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
+	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
+	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
+	at java.rmi/sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:360)
+	at java.rmi/sun.rmi.transport.Transport$1.run(Transport.java:200)
+	at java.rmi/sun.rmi.transport.Transport$1.run(Transport.java:197)
+	at java.base/java.security.AccessController.doPrivileged(AccessController.java:712)
+	at java.rmi/sun.rmi.transport.Transport.serviceCall(Transport.java:196)
+	at java.rmi/sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:587)
+	at java.rmi/sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:828)
+	at java.rmi/sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:705)
+	at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
+	at java.rmi/sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:704)
+	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
+	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
+	at java.base/java.lang.Thread.run(Thread.java:833)
+Caused by: org.h2.jdbc.JdbcSQLNonTransientException: Внутренняя ошибка: "org.h2.mvstore.MVStoreException: The file is locked: C:/Users/Admin/Downloads/IP/IP/data.mv.db [2.1.210/7]"
+General error: "org.h2.mvstore.MVStoreException: The file is locked: C:/Users/Admin/Downloads/IP/IP/data.mv.db [2.1.210/7]" [50000-210]
+	at org.h2.message.DbException.getJdbcSQLException(DbException.java:573)
+	at org.h2.message.DbException.getJdbcSQLException(DbException.java:496)
+	... 34 more
+Caused by: org.h2.mvstore.MVStoreException: The file is locked: C:/Users/Admin/Downloads/IP/IP/data.mv.db [2.1.210/7]
+	at org.h2.mvstore.DataUtils.newMVStoreException(DataUtils.java:1004)
+	at org.h2.mvstore.FileStore.open(FileStore.java:163)
+	at org.h2.mvstore.MVStore.<init>(MVStore.java:444)
+	... 28 more

src/main/java/ru/IP_LabWorks/IP/University/Contoller/DTO/StudentDTO.java

@@ -55,7 +55,7 @@ public class StudentDTO {
         this.name = name;
     }
 
-    public void setBirthDate(String birthDate){
+    public void setBirthDate(LocalDate birthDate){
-        this.birthDate = LocalDate.parse(birthDate, DateTimeFormatter.ofPattern("yyyy-MM-dd"));
+        this.birthDate = birthDate;
     }
 }

src/main/java/ru/IP_LabWorks/IP/University/Contoller/DTO/SubjectDTO.java

@@ -30,4 +30,7 @@ public class SubjectDTO {
         return groupIds;
     }
 
+    public void setName(String name){
+        this.name = name;
+    }
 }

src/main/java/ru/IP_LabWorks/IP/University/Contoller/MVC/GroupMvcController.java

@@ -1,15 +1,20 @@
 package ru.IP_LabWorks.IP.University.Contoller.MVC;
 
 import jakarta.validation.Valid;
+import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
 import org.springframework.validation.BindingResult;
 import org.springframework.web.bind.annotation.*;
 import ru.IP_LabWorks.IP.University.Contoller.DTO.GroupDTO;
 import ru.IP_LabWorks.IP.University.Contoller.DTO.StudentDTO;
+import ru.IP_LabWorks.IP.University.Model.Student;
+import ru.IP_LabWorks.IP.University.Model.Subject;
 import ru.IP_LabWorks.IP.University.Service.GroupService;
 import ru.IP_LabWorks.IP.University.Service.StudentService;
 
+import java.util.List;
+
 @Controller
 @RequestMapping("/group")
 public class GroupMvcController {
@@ -41,7 +46,7 @@ public class GroupMvcController {
         return "group-edit";
     }
 
-    @PostMapping(value = {"", "/{id}"})
+    @PostMapping(value = {"/", "/{id}"})
     public String saveGroup(@PathVariable(required = false) Long id,
                               @ModelAttribute @Valid GroupDTO groupDTO,
                               BindingResult bindingResult,
@@ -63,4 +68,18 @@ public class GroupMvcController {
         groupService.deleteGroup(id);
         return "redirect:/group";
     }
+
+    @GetMapping("/students/{id}")
+    public String getStudentsFromGroup(@PathVariable Long id, Model model) {
+        List<Student> students = groupService.getStudentFromGroup(id);
+        model.addAttribute("students", students);
+        return "view-students";
+    }
+
+    @GetMapping("/subjects/{id}")
+    public String getSubjectsFromGroup(@PathVariable Long id, Model model) {
+        List<Subject> subjects = groupService.getSubjectInGroup(id);
+        model.addAttribute("subjects", subjects);
+        return "view-subjects";
+    }
 }

src/main/java/ru/IP_LabWorks/IP/University/Contoller/MVC/StudentMvcController.java

@@ -1,14 +1,17 @@
 package ru.IP_LabWorks.IP.University.Contoller.MVC;
 
+import jakarta.validation.Valid;
 import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
 import org.springframework.validation.BindingResult;
-import org.springframework.web.bind.annotation.*;
+import org.springframework.web.bind.annotation.GetMapping;
-import ru.IP_LabWorks.IP.University.Contoller.DTO.GroupDTO;
+import org.springframework.web.bind.annotation.ModelAttribute;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
 import ru.IP_LabWorks.IP.University.Contoller.DTO.StudentDTO;
 import ru.IP_LabWorks.IP.University.Service.GroupService;
 import ru.IP_LabWorks.IP.University.Service.StudentService;
-import org.springframework.ui.Model;
-import jakarta.validation.Valid;
 
 @Controller
 @RequestMapping("/student")
@@ -34,9 +37,9 @@ public class StudentMvcController {
     @GetMapping(value = {"/edit", "/edit/{id}"})
     public String editStudent(@PathVariable(required = false) Long id,
                               Model model) {
+        model.addAttribute("Groups", groupService.findAllGroups());
         if (id == null || id <= 0) {
             model.addAttribute("studentDTO", new StudentDTO());
-            model.addAttribute("Groups", groupService.findAllGroups());
         } else {
             model.addAttribute("studentId", id);
             model.addAttribute("studentDTO", new StudentDTO(studentService.findStudent(id)));

src/main/java/ru/IP_LabWorks/IP/University/Contoller/MVC/SubjectMvcController.java

@@ -1,9 +1,85 @@
 package ru.IP_LabWorks.IP.University.Contoller.MVC;
 
+import jakarta.validation.Valid;
 import org.springframework.stereotype.Controller;
-import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.ui.Model;
+import org.springframework.validation.BindingResult;
+import org.springframework.web.bind.annotation.*;
+import ru.IP_LabWorks.IP.University.Contoller.DTO.SubjectDTO;
+import ru.IP_LabWorks.IP.University.Service.GroupService;
+import ru.IP_LabWorks.IP.University.Service.SubjectService;
+
+import java.util.List;
 
 @Controller
 @RequestMapping("/subject")
 public class SubjectMvcController {
+    private final SubjectService subjectService;
+
+    private final GroupService groupService;
+
+    public SubjectMvcController(SubjectService subjectService, GroupService groupService)
+    {
+        this.subjectService = subjectService;
+        this.groupService = groupService;
+    }
+
+    @GetMapping
+    public String getSubjects(Model model) {
+        model.addAttribute("subjects",
+                subjectService.findAllSubjects().stream()
+                        .map(SubjectDTO::new)
+                        .toList());
+        return "subject";
+    }
+
+    @GetMapping(value = {"/edit", "/edit/{id}"})
+    public String editSubject(@PathVariable(required = false) Long id,
+                            Model model) {
+        if (id == null || id <= 0) {
+            model.addAttribute("subjectDTO", new SubjectDTO());
+        } else {
+            model.addAttribute("subjectId", id);
+            model.addAttribute("subjectDTO", new SubjectDTO(subjectService.findSubject(id)));
+        }
+        return "subject-edit";
+    }
+
+    @PostMapping(value = {"/", "/{id}"})
+    public String saveSubject(@PathVariable(required = false) Long id,
+                            @ModelAttribute @Valid SubjectDTO subjectDTO,
+                            BindingResult bindingResult,
+                            Model model) {
+        if (bindingResult.hasErrors()) {
+            model.addAttribute("errors", bindingResult.getAllErrors());
+            return "subject-edit";
+        }
+        if (id == null || id <= 0) {
+            subjectService.addSubject(subjectDTO.getName());
+        } else {
+            subjectService.updateSubject(id, subjectDTO.getName());
+        }
+        return "redirect:/subject";
+    }
+
+    @PostMapping("/delete/{id}")
+    public String deleteSubject(@PathVariable Long id) {
+        subjectService.deleteSubject(id);
+        return "redirect:/subject";
+    }
+
+    @GetMapping("/addSubjectToGroup/{id}")
+    public String addSubjectToGroupForm(@PathVariable Long id, Model model) {
+        model.addAttribute("subjectDTO", new SubjectDTO(subjectService.findSubject(id)));
+        model.addAttribute("subjectId", id);
+        model.addAttribute("groups", groupService.findAllGroups());
+        return "add-subject-to-group";
+    }
+
+    @PostMapping("/addSubjectToGroup/{id}")
+    public String addSubjectToGroup(@PathVariable Long id,
+                                    @RequestParam("groupId") List<Long> groupIds) {
+        subjectService.addSubjectToGroup(id, groupIds);
+        return "redirect:/subject";
+    }
 }

src/main/resources/templates/add-subject-to-group.html

@@ -0,0 +1,38 @@
+<!DOCTYPE html>
+<html lang="en"
+      xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout"
+      layout:decorate="~{default}">
+<head>
+</head>
+<body>
+<div layout:fragment="content">
+  <div th:text="${errors}" class="margin-bottom alert-danger"></div>
+  <form action="#" th:action="@{/subject/addSubjectToGroup/{id}(id=${subjectId})}" method="post">
+    <div class="mb-3">
+      <label for="name" class="form-label">Название</label>
+      <input type="text" class="form-control" id="name" th:field="${subjectDTO.name}" readonly>
+    </div>
+    <div class="form-group">
+      <label for="name">Выберите группы для добавления:</label>
+      <ul class="list-group">
+        <li class="list-group-item" th:each="group, iterator: ${groups}">
+          <div class="form-check">
+            <input class="form-check-input" type="checkbox" th:id="'groupId-' + ${group.id}"
+                   th:value="${group.id}" th:checked="${subjectDTO.groupIds.contains(group.id)}" name="groupId">
+            <label class="form-check-label" th:for="'groupId-' + ${group.id}" th:text="${group.name}"></label>
+          </div>
+        </li>
+      </ul>
+    </div>
+    <div class="mb-3">
+      <button type="submit" class="btn btn-primary button-fixed">
+        <span>Добавить</span>
+      </button>
+      <a class="btn btn-secondary button-fixed" th:href="@{/subject}">
+        Назад
+      </a>
+    </div>
+  </form>
+</div>
+</body>
+</html>

src/main/resources/templates/default.html

@@ -24,6 +24,7 @@
       <ul class="navbar-nav">
         <a class="nav-link" href="/student" th:classappend="${#strings.equals(activeLink, '/student')} ? 'active' : ''">Студенты</a>
         <a class="nav-link" href="/group" th:classappend="${#strings.equals(activeLink, '/group')} ? 'active' : ''">Группы</a>
+          <a class="nav-link" href="/subject" th:classappend="${#strings.equals(activeLink, '/subject')} ? 'active' : ''">Предметы</a>
       </ul>
     </div>
   </div>

src/main/resources/templates/group-edit.html

@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<html lang="en"
+      xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout"
+      layout:decorate="~{default}">
+<head>
+</head>
+<body>
+<div layout:fragment="content">
+  <div th:text="${errors}" class="margin-bottom alert-danger"></div>
+  <form action="#" th:action="@{/group/{id}(id=${id})}" th:object="${groupDTO}" method="post">
+    <div class="mb-3">
+      <label for="name" class="form-label">Название</label>
+      <input type="text" class="form-control" id="name" th:field="${groupDTO.name}" required="true">
+    </div>
+    <div class="mb-3">
+      <button type="submit" class="btn btn-primary button-fixed">
+        <span th:if="${groupId == null}">Добавить</span>
+        <span th:if="${groupId != null}">Обновить</span>
+      </button>
+      <a class="btn btn-secondary button-fixed" th:href="@{/group}">
+        Назад
+      </a>
+    </div>
+  </form>
+</div>
+</body>
+</html>

src/main/resources/templates/group.html

@@ -4,7 +4,49 @@
       layout:decorate="~{default}">
 <body>
 <div layout:fragment="content">
-
+    <h1 class="text-center mb-4">Group Table</h1>
+    <div>
+        <a class="btn btn-success button-fixed"
+           th:href="@{/group/edit}">
+            <i class="fa-solid fa-plus"></i> Добавить
+        </a>
+    </div>
+    <div class="table-responsive">
+        <table class="table">
+            <thead>
+            <tr>
+                <th scope="col">Название</th>
+                <th scope="col"></th>
+            </tr>
+            </thead>
+            <tbody>
+            <tr th:each="group, iterator: ${groups}">
+                <td th:text="${group.name}"></td>
+                <td>
+                    <div class="btn-group" role="group" aria-label="Basic example">
+                        <a class="btn btn-warning button-fixed button-sm"
+                           th:href="@{/group/edit/{id}(id=${group.id})}">
+                            <i class="fa fa-pencil" aria-hidden="true"></i> Изменить
+                        </a>
+                        <button type="button" class="btn btn-danger button-fixed button-sm"
+                                th:attr="onclick=|confirm('Удалить запись?') && document.getElementById('remove-${group.id}').click()|">
+                            <i class="fa fa-trash" aria-hidden="true"></i> Удалить
+                        </button>
+                        <a class="btn btn-primary button-fixed button-sm"
+                           th:href="@{/group/students/{id}(id=${group.id})}">Посмотреть студентов</a>
+                        <a class="btn btn-primary button-fixed button-sm"
+                           th:href="@{/group/subjects/{id}(id=${group.id})}">Посмотреть предметы</a>
+                    </div>
+                    <form th:action="@{/group/delete/{id}(id=${group.id})}" method="post">
+                        <button th:id="'remove-' + ${group.id}" type="submit" style="display: none">
+                            Удалить
+                        </button>
+                    </form>
+                </td>
+            </tr>
+            </tbody>
+        </table>
+    </div>
 </div>
 </body>
 </html>

src/main/resources/templates/student-edit.html

@@ -7,7 +7,7 @@
 <body>
 <div layout:fragment="content">
   <div th:text="${errors}" class="margin-bottom alert-danger"></div>
-  <form action="#" th:action="@{/student/{id}(id=${id})}" th:object="${studentDTO}" method="post">
+  <form action="#" th:action="@{/student}" th:object="${studentDTO}" method="post">
     <div class="mb-3">
       <label for="name" class="form-label">ФИО</label>
       <input type="text" class="form-control" id="name" th:field="${studentDTO.name}" required="true">
@@ -24,8 +24,8 @@
     </div>
     <div class="mb-3">
       <button type="submit" class="btn btn-primary button-fixed">
-        <span th:if="${id == null}">Добавить</span>
+        <span th:if="${studentId == null}">Добавить</span>
-        <span th:if="${id != null}">Обновить</span>
+        <span th:if="${studentId != null}">Обновить</span>
       </button>
       <a class="btn btn-secondary button-fixed" th:href="@{/student}">
         Назад

src/main/resources/templates/student.html

@@ -1,9 +1,12 @@
 <!DOCTYPE html>
 <html lang="en"
       xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout"
-      layout:decorate="~{default}">
+      layout:decorate="~{default}" xmlns:th="http://www.w3.org/1999/xhtml">
+<head>
+</head>
 <body>
 <div layout:fragment="content">
+    <h1 class="text-center mb-4">Student Table</h1>
     <div>
         <a class="btn btn-success button-fixed"
            th:href="@{/student/edit}">

src/main/resources/templates/subject-edit.html

@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<html lang="en"
+      xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout"
+      layout:decorate="~{default}">
+<head>
+</head>
+<body>
+<div layout:fragment="content">
+  <div th:text="${errors}" class="margin-bottom alert-danger"></div>
+  <form action="#" th:action="@{/subject/{id}(id=${id})}" th:object="${subjectDTO}" method="post">
+    <div class="mb-3">
+      <label for="name" class="form-label">Название</label>
+      <input type="text" class="form-control" id="name" th:field="${subjectDTO.name}" required="true">
+    </div>
+    <div class="mb-3">
+      <button type="submit" class="btn btn-primary button-fixed">
+        <span th:if="${subjectId == null}">Добавить</span>
+        <span th:if="${subjectId != null}">Обновить</span>
+      </button>
+      <a class="btn btn-secondary button-fixed" th:href="@{/subject}">
+        Назад
+      </a>
+    </div>
+  </form>
+</div>
+</body>
+</html>

src/main/resources/templates/subject.html

@@ -4,7 +4,49 @@
       layout:decorate="~{default}">
 <body>
 <div layout:fragment="content">
-
+    <h1 class="text-center mb-4">Subject Table</h1>
+    <div>
+        <a class="btn btn-success button-fixed"
+           th:href="@{/subject/edit}">
+            <i class="fa-solid fa-plus"></i> Добавить
+        </a>
+    </div>
+    <div class="table-responsive">
+        <table class="table">
+            <thead>
+            <tr>
+                <th scope="col">Название</th>
+                <th scope="col"></th>
+            </tr>
+            </thead>
+            <tbody>
+            <tr th:each="subject, iterator: ${subjects}">
+                <td th:text="${subject.name}"></td>
+                <td>
+                    <div class="btn-group" role="group" aria-label="Basic example">
+                        <a class="btn btn-warning button-fixed button-sm"
+                           th:href="@{/subject/edit/{id}(id=${subject.id})}">
+                            <i class="fa fa-pencil" aria-hidden="true"></i> Изменить
+                        </a>
+                        <button type="button" class="btn btn-danger button-fixed button-sm"
+                                th:attr="onclick=|confirm('Удалить запись?') && document.getElementById('remove-${subject.id}').click()|">
+                            <i class="fa fa-trash" aria-hidden="true"></i> Удалить
+                        </button>
+                        <a class="btn btn-primary button-fixed button-sm"
+                           th:href="@{/subject/addSubjectToGroup/{id}(id=${subject.id})}">
+                            <i class="fa fa-pencil" aria-hidden="true"></i> Добавить предметы в группы
+                        </a>
+                    </div>
+                    <form th:action="@{/subject/delete/{id}(id=${subject.id})}" method="post">
+                        <button th:id="'remove-' + ${subject.id}" type="submit" style="display: none">
+                            Удалить
+                        </button>
+                    </form>
+                </td>
+            </tr>
+            </tbody>
+        </table>
+    </div>
 </div>
 </body>
 </html>

src/main/resources/templates/view-students.html

@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<html lang="en"
+      xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout"
+      layout:decorate="~{default}">
+<head>
+</head>
+<body>
+<div layout:fragment="content">
+  <div class="table-responsive">
+    <table class="table">
+      <thead>
+      <tr>
+        <th scope="col">ФИО</th>
+        <th scope="col">Дата рождения</th>
+      </tr>
+      </thead>
+      <tbody>
+      <tr th:each="student, iterator: ${students}">
+        <td th:text="${student.name}"></td>
+        <td th:text="${student.birthDate}"></td>
+      </tr>
+      </tbody>
+      <a class="btn btn-secondary button-fixed" th:href="@{/group}">
+        Назад
+      </a>
+    </table>
+  </div>
+</div>
+</body>
+</html>

src/main/resources/templates/view-subjects.html

@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html lang="en"
+      xmlns:layout="http://www.ultraq.net.nz/thymeleaf/layout"
+      layout:decorate="~{default}">
+<head>
+</head>
+<body>
+<div layout:fragment="content">
+  <div class="table-responsive">
+    <table class="table">
+      <thead>
+      <tr>
+        <th scope="col">Название</th>
+      </tr>
+      </thead>
+      <tbody>
+      <tr th:each="subject, iterator: ${subjects}">
+        <td th:text="${subject.name}"></td>
+      </tr>
+      </tbody>
+      <a class="btn btn-secondary button-fixed" th:href="@{/group}">
+        Назад
+      </a>
+    </table>
+  </div>
+</div>
+</body>
+</html>