RouterFunction的webflux

RouterFunction可以运行在servlet或netty上，所以我们需要将两个容器间的不同点抽象出来。

整个开发过程有几步：

1.HandleFunction，实现输入ServerRequest，输出ServerResponse

2.RouterFunction，把请求url和HandlerFunction对应起来

3.把RouterFunction包装成HttpHandler，交给容器Server处理。

代码：

实体类和仓库不变

handler：

@Component
public class UserHandler {
    private final UserRepository repository;

    public UserHandler(UserRepository repository) {
        this.repository = repository;
    }

    public Mono<ServerResponse> getAllUser(ServerRequest request){
        return ServerResponse.ok().contentType(MediaType.APPLICATION_JSON)
                .body(repository.findAll() , User.class);
    }
    public Mono<ServerResponse> createUser(ServerRequest request){
        Mono<User> userMono = request.bodyToMono(User.class);
        return ServerResponse.ok().contentType(MediaType.APPLICATION_JSON)
                .body(repository.saveAll(userMono) , User.class);
    }
    public Mono<ServerResponse> deleteUserById(ServerRequest request){
        String id = request.pathVariable("id");
        return this.repository.findById(id)
                .flatMap(user -> this.repository.delete(user)
                        .then(ServerResponse.ok().build()))
                .switchIfEmpty(ServerResponse.notFound().build());
    }
}
           

router：

@Configuration
public class AllRouters {
    @Bean
    RouterFunction<ServerResponse> userRouter(UserHandler handler){
        return RouterFunctions.nest(
                //相当于requestMapping
                RequestPredicates.path("/user") ,
                RouterFunctions.route(RequestPredicates.GET("/") , handler::getAllUser)
                    .andRoute(RequestPredicates.POST("/").and(RequestPredicates.accept(MediaType.APPLICATION_JSON)) , handler::createUser)
                    .andRoute(RequestPredicates.DELETE("/{id}") , handler::deleteUserById));

    }
}
           

接下来看看routerFunction下的参数校验：

改造下代码（这里只写一个做例子）

public Mono<ServerResponse> createUser(ServerRequest request){
        Mono<User> userMono = request.bodyToMono(User.class);
        return userMono.flatMap(user -> {
            //在这里做校验
            //xxx
            return ServerResponse.ok().contentType(MediaType.APPLICATION_JSON)
                    .body(repository.saveAll(userMono) , User.class);
        });
    }
           

异常捕获，用aop的方式：

@Component
@Order(-99)
public class ExceptionHandler implements WebExceptionHandler {
    @Override
    public Mono<Void> handle(ServerWebExchange serverWebExchange, Throwable throwable) {
        ServerHttpResponse response = serverWebExchange.getResponse();
        response.setStatusCode(HttpStatus.BAD_REQUEST);
        response.getHeaders().setContentType(MediaType.TEXT_PLAIN);
        String errorMsg = toStr(throwable);
        DataBuffer db = response.bufferFactory().wrap(errorMsg.getBytes());
        return response.writeWith(Mono.just(db));
    }

    private String toStr(Throwable throwable) {
        //已知异常，自定义异常，这里懒得写了，就随便找一个代替
        if (throwable instanceof NumberFormatException){
            NumberFormatException e = (NumberFormatException) throwable;
            return e.getMessage();
        }
        //未知异常
        else {
            throwable.printStackTrace();
            return throwable.toString();
        }
    }
}