[英]How to get model attributes when using Spring WebFlux router functions?
Spring WebFlux提供两种编程选项:带注释的控制器和功能端点。 有了第一个,我们可以使用@ModelAttribute
注解将model属性从controller转移到视图(如Thymeleaf html-template),反之亦然但是,当涉及到路由器功能时,到目前为止,我刚刚弄清楚如何将 model 属性附加到ServerResponse
,但找不到将它们取回的方法。 考虑以下代码片段:
@Configuration
public class StudentsRouterFunctions {
// inject repository
private final StudentsCrudRepository repo;
public StudentsRouterFunctions(StudentsCrudRepository repo) {
this.repo = repo;
}
@Bean
RouterFunction<?> routs() {
return RouterFunctions.route()
.GET("/students", this::showStudents)
.POST("/students", this::saveStudent)
.build();
}
// #1: GET-handler
private Mono<ServerResponse> showStudents(ServerRequest request) {
// set model attributes
Map<String, Object> model = new HashMap<>();
Mono<Student> studentsList = repo.findAll().collectList();
Mono<Student> newStudent = Mono.just(new Student());
model.put("students", studentsList);
model.put("studentForm", newStudent);
// render the view
return ServerResponse.ok()
.contentType(MediaType.TEXT_HTML)
.render("students-template", model);
}
// #2: POST-handler
private Mono<ServerResponse> saveStudent(ServerRequest request) {
// and here I somehow need to get my new student object
// back from the view via "studentForm" model attribute
// Student newStudent = request.getModel().get("studentForm");
// !!! however, ServerRequest.getModel() method doesn't exist
return repo.save(newStudent)
.then(ServerResponse.status(HttpStatus.PERMANENT_REDIRECT)
.render("redirect:/students", new Object()));
}
没有ServerRequest::getModel
方法,但ServerRequest::bodyToMono(Class)
将您的 model 所在的主体提取到Mono<T>
。
然后利用响应式存储库的方法ReactiveCrudRepository::save
的返回类型的优势,使用Mono::flatMap
返回Mono<T>
。
我还没有测试过,但它应该可以工作。
private Mono<ServerResponse> saveStudent(ServerRequest request) {
return request.bodyToMono(Student.class) // Mono<Student> (a new one)
.flatMap(repo::save) // Mono<Student> (a saved one)
.then(ServerResponse // redirect sequence
.status(HttpStatus.PERMANENT_REDIRECT)
.render("redirect:/students", new Object()));
}
// .flatMap(repo::save) is the same as .flatMap(newStudent -> repo.save(newStudent))
Note the method Mono::then
the element from the source so the redirected object remains as a new Object()
, so you want to use Mono::map
.
private Mono<ServerResponse> saveStudent(ServerRequest request) {
return request.bodyToMono(Student.class) // Mono<Student> (a new one)
.flatMap(repo::save) // Mono<Student> (a saved one)
.map(savedStudent -> ServerResponse // redirect sequence
.status(HttpStatus.PERMANENT_REDIRECT)
.render("redirect:/students", savedStudent));
}
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