我有几个实体，我可以保存讲师的 ID、姓名、姓氏、城市、地址，但我可以使用 thymeleaf 形式在 car_id 上设置他的引用。在引导加载程序上，这很好
模板解析时发生错误(模板:“类路径资源[templates/index.html]”) org.thymeleaf.exceptions.TemplateInputException:模板解析期间发生错误(模板:“类路径资源[templates/index.html]”) 引起原因:org.attoparser.ParseException:计算 SpringEL 表达式时出现异常:“car.getInstructor().id”(模板:“index” - 第 84 行，第 13 列)
在教练课上我这样做了
@OneToOne(级联= CascadeType.ALL，获取= FetchType.LAZY)
私家车；
在汽车课上我这样做了
@一对一
私有(private)教练教练；
<body>
<form th:object="${instructor}" th:action="@{/instructor/}" method="post">
<input type="hidden" th:field="*{id}"/>
First name<br>
<input type="text" class="form-control" th:field="*{firstName}"/><br>
Last name <br>
<input type="text" class="form-control" th:field="*{lastName}"/><br>
City <br>
<input type="text" class="form-control" th:field="*{city}"/><br>
Address <br>
<input type="text" class="form-control" th:field="*{address}"/><br>
<input type="number" class="form-control" th:field="*{car.id}"/><br>
<button type="submit">Submit</button>
</form>
</body>
@Slf4j @ Controller 公共(public)类 IndexController {
private final InstructorService instructorService;
private final StudentService studentService;
private final CarService carService;
private final CarDrivingClassService carDrivingClassService;
public IndexController(InstructorService instructorService, StudentService studentService, CarService carService, CarDrivingClassService carDrivingClassService) {
this.instructorService = instructorService;
this.studentService = studentService;
this.carService = carService;
this.carDrivingClassService = carDrivingClassService;
}
@RequestMapping({"", "/", "/index"})
public String getIndexPage(Model model) {
System.out.println("Getting Index page");
model.addAttribute("cars",carService.findAll());
model.addAttribute("instructors", instructorService.findAll());
model.addAttribute("students", studentService.findAll());
return "index";
}
@GetMapping("/new")
public String newRecipe(Model model){
model.addAttribute("instructor", new InstructorCommand());
return "/form";
}
@PostMapping("instructor")
@Transactional
public String saveOrUpdate(@ModelAttribute InstructorCommand command){
InstructorCommand savedCommand = instructorService.saveInstructorCommand(command);
return "redirect:/";
}
}
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
@Entity
@Table(name="cars")
public class Car extends BaseEntity{
@Column(name = "name")
private String name;
@OneToOne
private Instructor instructor;
}
@Setter
@Getter
@NoArgsConstructor
@AllArgsConstructor
@Builder
@Entity
@Table(name="instructors")
public class Instructor extends Person{
@OneToMany(mappedBy = "instructor")
public Set<Student> students = new HashSet<>();
@OneToOne(cascade = CascadeType.ALL,fetch = FetchType.LAZY)
private Car car;
}
最佳答案
我正在用这个加载数据
@Component
public class Bootstrap implements CommandLineRunner {
private final CarService carService;
private final StudentService studentService;
private final InstructorService instructorService;
private final CarDrivingClassService carDrivingClassService;
public Bootstrap(CarService carService, StudentService studentService, InstructorService instructorService, CarDrivingClassService carDrivingClassService) {
this.carService = carService;
this.studentService = studentService;
this.instructorService = instructorService;
this.carDrivingClassService = carDrivingClassService;
}
@Override
public void run(String... args) throws Exception {
Date date = new SimpleDateFormat( "yyyyMMdd" ).parse( "19970807" );
Date date2 = new SimpleDateFormat( "yyyyMMdd" ).parse( "20192304" );
Date date3 = new SimpleDateFormat( "yyyyMMdd" ).parse( "20192404" );
Date date4 = new SimpleDateFormat( "yyyyMMdd" ).parse( "20192505" );
/*Creating a student*/
Student student = new Student();
student.setFirstName("Bob");
student.setLastName("Rock");
student.setBirthDate(date);
student.setCity("Miami");
student.setAddress("Lincoln Road");
student.setPostalCode(45300);
Student student2 = new Student();
student2.setFirstName("John");
student2.setLastName("Smith");
student2.setBirthDate(date);
student2.setCity("Miami");
student2.setAddress("Old Cutler Road and Ingraham Highway");
student2.setPostalCode(45100);
/*Class that will save our classes for driving*/
CarDrivingClass savedDrivingClasses;
//Create 20 car driving classes and save them in table CLASSES
for(int i = 0; i<20; i++){
CarDrivingClass tempClass = new CarDrivingClass();
tempClass.setDate(date3);
savedDrivingClasses = carDrivingClassService.save(tempClass);
/*
Fill table STUDENT_CLASSES
* */
student.getClasses().add(savedDrivingClasses);
student2.getClasses().add(savedDrivingClasses);
System.out.println("Saving "+(i+1)+ ". class");
}
/*Instructor one*/
Instructor instructor = new Instructor();
instructor.setFirstName("Dave");
instructor.setLastName("Joe");
instructor.setCity("Miami");
instructor.setAddress("Miami 001");
instructor.setPostalCode(45400);
/*Instructor two*/
Instructor instructor2 = new Instructor();
instructor2.setFirstName("Clark");
instructor2.setLastName("Kent");
instructor2.setCity("LA");
instructor2.setAddress("South Martel Avenue");
instructor2.setPostalCode(95400);
/*Car num one*/
Car audi = new Car();
audi.setName("Audi A7");
audi.setInstructor(instructor);
/*Car num two*/
Car BMW = new Car();
BMW.setName("BMW M4");
BMW.setInstructor(instructor2);
/*Adding car to instructors*/
instructor.setCar(audi);
instructor2.setCar(BMW);
/*Associate student with instructor*/
student.setInstructor(instructor);
student2.setInstructor(instructor);
//Saving into db with services
instructorService.save(instructor);
instructorService.save(instructor2);
studentService.save(student);
studentService.save(student2);
carService.save(audi);
carService.save(BMW);
}
}
数据显示正常
<h1>Instructors</h1>
<table>
<thead>
<tr>
<th>ID</th>
<th>Name</th>
<th>Surname</th>
<th>City</th>
<th>Address</th>
<th>Car</th>
</tr>
</thead>
<tr th:remove="all">
<td>123</td>
<td>Tasty Goodnees 1</td>
<td><a href="#">View</a></td>
</tr>
<tr th:each="instructor : ${instructors}">
<td th:text="${instructor.id}">334</td>
<td th:text="${instructor.firstName}">Tasty Goodnees 3</td>
<td th:text="${instructor.lastName}">Tasty Goodnees 3</td>
<td th:text="${instructor.city}">Tasty Goodnees 3</td>
<td th:text="${instructor.address}">Tasty Goodnees 3</td>
<td th:text="${instructor.getCar().id}">Tasty Goodnees 3</td> <!--getting car id -->
</tr>
</table>
但是当我添加一个新的教练时，它在索引表单中向我显示 ${instructor.getCar().id 的错误，我可以添加教练，而无需表单中 id 的输入字段以及 index.html 中的这行代码 美味的古德尼斯 3
关于java - 无法在教练类(class)上设置教练 car_id，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/58050100/