WebFlux + Thymeleaf

타임리프 ( thymeleaf )

spring.thymeleaf.prefix= ViewResolver를 사용하기 위한 접두사, 기본값 classpath:/templates/
spring.thymeleaf.suffix= 접미사, 기본값 .html
spring.thymeleaf.encoding= template의 인코딩, 기본값 UTF-8
spring.thymeleaf.check-template= 렌더링되기 전에 템플릿이 존재하는지 확인, 기본값 true
spring.thymeleaf.check-template-location= 템플릿 ㅜ이치가 존재하는지 확인, 기본값 true
spring.thymeleaf.mode= 타임리프를 사용하기 위한 TemplateMode, 기본값 HTML
spring.thymeleaf.cache= 템플릿을 캐시할 것인지 아닌지 설정, 기본값 true
spring.thymeleaf.template-resolver-order= ViewResolver의 순서, 기본값 1
spring.thymeleaf.view-names= ViewResolver로 해결할 수 있는 뷰 이름. 쉼표로 구분
spring.thymeleaf.excluded-view-names= 제외시켜야할 뷰 이름. 쉼표로 구분
spring.thymeleaf.enabled= 타임리프 동작 유무. 기본값 true
spring.thymeleaf.enable-spring-el-compiler= SpEL 표현법의 컴파일 사용 여부. 기본값 false
spring.thymeleaf.reactive.max-chunk-size= 응답을 쓰는 데 사용할 데이터 버퍼의 최대 크기. 기본값 0
spring.thymeleaf.reactive.media-types= text/html과 같은 뷰 기술에 의해 지원되는 미디어 유형
spring.thymeleaf.reactive.full-mode-view-names= FULL 모드에서 동작해야 하는 쉼표로 구분된 목록의 뷰 이름. 기본값은 겂고 FULL
모드는 기본적으로 차단 모드를 의미
spring.thymeleaf.reactive.chunked-mode-view-names= chunked 모드에서 동작해야 하는 쉼표로 구분된 목록의 뷰 이름

---

사이트)

https://mkyong.com/spring-boot/spring-boot-webflux-thymeleaf-reactive-example/

https://mkyong.com/spring-boot/spring-boot-webflux-server-sent-events-example/

http://wiki.sys4u.co.kr/pages/viewpage.action?pageId=8552646

https://dzone.com/articles/spring-webflux-a-basic-crud-application-part-1

https://springframework.guru/spring-web-reactive/

https://www.baeldung.com/spring-webflux

https://stackoverflow.com/questions/51377675/does-not-the-spring-boot-starter-web-and-spring-boot-starter-webflux-work-togeth

https://freedeveloper.tistory.com/80

실습전 주의사항

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

starter-web을 pom.xml에서 빼주어야됩니다. 

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-webflux</artifactId>
</dependency>

기존에 webflux와 같이 pom.xml에 있으면 webflux는 제기능을 못합니다.

자세한것은 아래 Reference 문서를 보시면 되겠습니다.

애플리케이션에 모듈 spring-boot-starter-web과 spring-boot-starter-webflux모듈을 모두 추가하면 WebFlux가 아닌 Spring Boot 자동 구성 Spring MVC가 생성됩니다. 이 동작은 많은 Spring 개발자 spring-boot-starter-webflux가 반응성을 사용하기 위해 Spring MVC 애플리케이션에 추가 하기 때문에 선택되었습니다 WebClient. 선택한 애플리케이션 유형을로 설정하여 선택을 계속 적용 할 수 있습니다 SpringApplication.setWebApplicationType(WebApplicationType.REACTIVE). 출처 : https://docs.spring.io/spring-boot/docs/current/reference/html/spring-boot-features.html#boot-features-developing-web-applications

에러걸리시 뜨는 페이지)

Whitelabel Error Page

This application has no explicit mapping for /error, so you are seeing this as a fallback.

Sun Feb 09 03:33:41 KST 2020

There was an unexpected error (type=Internal Server Error, status=500).

An error happened during template parsing (template: "class path resource [templates/list.html]")

2020-02-09 03:33:41.673 ERROR 7248 --- [nio-8080-exec-7] org.thymeleaf.TemplateEngine             : [THYMELEAF][http-nio-8080-exec-7] Exception processing template "list": An error happened during template parsing (template: "class path resource [templates/list.html]")
 
org.thymeleaf.exceptions.TemplateInputException: An error happened during template parsing (template: "class path resource [templates/list.html]")
...
 
Caused by: org.attoparser.ParseException: Exception evaluating SpringEL expression: "movie.name" (template: "list" - line 21, col 21)
...
 
Caused by: org.thymeleaf.exceptions.TemplateProcessingException: Exception evaluating SpringEL expression: "movie.name" (template: "list" - line 21, col 21)
...
 
Caused by: org.springframework.expression.spel.SpelEvaluationException: EL1008E: Property or field 'name' cannot be found on object of type 'reactor.core.publisher.FluxConcatMap' - maybe not public or not valid?
...
 
2020-02-09 03:33:41.673 DEBUG 7248 --- [nio-8080-exec-7] o.s.web.servlet.DispatcherServlet        : Error rendering view [org.thymeleaf.spring5.view.ThymeleafView@27d95d1f]
 
org.thymeleaf.exceptions.TemplateInputException: An error happened during template parsing (template: "class path resource [templates/list.html]")
...
 
Caused by: org.attoparser.ParseException: Exception evaluating SpringEL expression: "movie.name" (template: "list" - line 21, col 21)
...
 
Caused by: org.thymeleaf.exceptions.TemplateProcessingException: Exception evaluating SpringEL expression: "movie.name" (template: "list" - line 21, col 21)
...
 
Caused by: org.springframework.expression.spel.SpelEvaluationException: EL1008E: Property or field 'name' cannot be found on object of type 'reactor.core.publisher.FluxConcatMap' - maybe not public or not valid?
...
 
2020-02-09 03:33:41.674 DEBUG 7248 --- [nio-8080-exec-7] o.s.web.servlet.DispatcherServlet        : Unresolved failure from "ASYNC" dispatch: org.thymeleaf.exceptions.TemplateInputException: An error happened during template parsing (template: "class path resource [templates/list.html]")
2020-02-09 03:33:41.674 ERROR 7248 --- [nio-8080-exec-7] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] threw exception
 
org.springframework.expression.spel.SpelEvaluationException: EL1008E: Property or field 'name' cannot be found on object of type 'reactor.core.publisher.FluxConcatMap' - maybe not public or not valid?
...
 
2020-02-09 03:33:41.674 ERROR 7248 --- [nio-8080-exec-7] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.thymeleaf.exceptions.TemplateInputException: An error happened during template parsing (template: "class path resource [templates/list.html]")] with root cause
 
org.springframework.expression.spel.SpelEvaluationException: EL1008E: Property or field 'name' cannot be found on object of type 'reactor.core.publisher.FluxConcatMap' - maybe not public or not valid?
...
 
2020-02-09 03:33:41.675 DEBUG 7248 --- [nio-8080-exec-7] o.s.web.servlet.DispatcherServlet        : "ERROR" dispatch for GET "/error", parameters={}
2020-02-09 03:33:41.675 DEBUG 7248 --- [nio-8080-exec-7] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController#errorHtml(HttpServletRequest, HttpServletResponse)
2020-02-09 03:33:41.677 DEBUG 7248 --- [nio-8080-exec-7] o.s.w.s.v.ContentNegotiatingViewResolver : Selected 'text/html' given [text/html, text/html;q=0.8]
2020-02-09 03:33:41.677 DEBUG 7248 --- [nio-8080-exec-7] o.s.web.servlet.DispatcherServlet        : Exiting from "ERROR" dispatch, status 500

해결법1)

https://freedeveloper.tistory.com/80

https://okky.kr/article/456316

https://junjangsee.github.io/2019/04/30/spring/spring-06/

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.WebApplicationType;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication application = new SpringApplication(DemoApplication.class);
        application.setWebApplicationType(WebApplicationType.REACTIVE); 
        // starter-web은 SERVLET으로 자동으로 선택한다. 이것을 강제로 REACTIVE로 바꾼다.
        application.run(args);
    }
}

해결법2)

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

을 삭제

---

실행화면1)

package com.example.demo.Domain;

public class Movie {

    private String name;
    private Integer score;

    public Movie() {
    }

    public Movie(String name, Integer score) {
        this.name = name;
        this.score = score;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getScore() {
        return score;
    }

    public void setScore(Integer score) {
        this.score = score;
    }
}

package com.example.demo.Repository;

import com.example.demo.Domain.Movie;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

public interface MovieRepository {

    Flux<Movie> findAll();
    Mono<Movie>  findById(String id);
    Mono<Movie> save(Mono<Movie> order);
    Movie save(Movie movie);
}

package com.example.demo.Repository;

import com.example.demo.Domain.Movie;
import org.springframework.stereotype.Repository;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import javax.annotation.PostConstruct;
import java.time.Duration;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.ThreadLocalRandom;

@Repository
public class ReactiveMovieRepository implements MovieRepository {

    private static List<Movie> movie = new ArrayList<>();
    // 1차
    static {
        movie.add(new Movie("Polar (2019)", 64));
        movie.add(new Movie("Iron Man (2008)", 79));
        movie.add(new Movie("The Shawshank Redemption (1994)", 93));
        movie.add(new Movie("Forrest Gump (1994)", 83));
        movie.add(new Movie("Glass (2019)", 70));
    }
    // 2차
    @PostConstruct
    public void init() {
        for (int i = 0; i < 25; i++ ) {
            var Mov = generate();
            movie.add(Mov);
        }
    }

    @Override
    public Flux<Movie> findAll() {
        //simulate stream data with 2 seconds delay.
        return Flux.fromIterable(movie).delayElements(Duration.ofMillis(100));
    }

    @Override
    public Mono<Movie> findById(String id) {
        Movie movieItem = null;
        movieItem = containsId(id);
        if(movieItem == null){
            return null;
        }
        return Mono.just(movieItem);
    }

    @Override
    public Mono<Movie> save(Mono<Movie> order) {
        return order.map(this::save);
    }

    @Override
    public Movie save(Movie movieItem) {
        movie.add(movieItem);
        return movieItem;
    }

    public Movie generate() {
        var amount = ThreadLocalRandom.current().nextInt(1000);
        return new Movie(UUID.randomUUID().toString(), amount);
    }

    public static Movie containsId(String id) {
        for (Movie object : movie) {
            if (object.getName() == id) {
                return object;
            }
        }
        return null;
    }
}

package com.example.demo.Controller;

import com.example.demo.Repository.MovieRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.thymeleaf.spring5.context.webflux.IReactiveDataDriverContextVariable;
import org.thymeleaf.spring5.context.webflux.ReactiveDataDriverContextVariable;
import reactor.core.publisher.Mono;

@Controller
public class MovieController {

    @Autowired
    private MovieRepository movieRepository;

    @RequestMapping("/")
    public String index(final Model model) {

        // loads 1 and display 1, stream data, data driven mode.
        IReactiveDataDriverContextVariable reactiveDataDrivenMode =
                new ReactiveDataDriverContextVariable(movieRepository.findAll(), 1);

        model.addAttribute("movies", reactiveDataDrivenMode);

        // classic, wait repository loaded all and display it.
        //model.addAttribute("movies", movieRepository.findAll());

        return "index";
    }

    @RequestMapping("/list")
    public Mono<String> list(Model model) {
        var movies = movieRepository.findAll();
        model.addAttribute("movies", movies);
        return Mono.just("list");
    }
}

index.html

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link data-th-href="@{/css/bootstrap.min.css}" rel="stylesheet">
    <link data-th-href="@{/css/main.css}" rel="stylesheet">
</head>
<body>

<div class="container">

    <div class="row">
        <div id="title">
            <h1>Spring WebFlux + Thymeleaf</h1>
        </div>
        <table id="allMovies" class="table table-striped">
            <thead>
            <tr>
                <th width="50%">Name</th>
                <th>Score</th>
            </tr>
            </thead>

            <tbody>
            <tr class="result" data-th-each="movie : ${movies}">
                <td>[[${movie.name}]]</td>
                <td>[[${movie.score}]]</td>
            </tr>
            </tbody>
        </table>
    </div>


</div>

list.html

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Orders</title>
</head>
<body>
<h1>Orders</h1>

    <table>
        <thead>
            <tr>
               <th></th>
                <th>Id</th>
                <th>Amount</th>
            </tr>
        </thead>
        <tbody>
            <tr th:each="movie : ${movies}">
               <td th:text="${movieStat.count}">1</td>
                <td th:text="${movie.name}"></td>
                <td th:text="${#numbers.formatCurrency(movie.score)}" style="text-align: right"></td>
            </tr>
        </tbody>
    </table>

</body>
</html>

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>11</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>io.projectreactor</groupId>
            <artifactId>reactor-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

springboot2_Reactive_example2.zip