Spring应用程序返回空JSON

Question

我开始阅读"学习Spring Boot 2.0 - 第二版:简化基于微服务和反应式编程的快速闪存应用程序的开发",并且遇到了第一个示例程序之一的问题.

当我http://localhost:8080/chapters对它进行GET 返回时:

[
    {},
    {},
    {}
]

代替:

[
    {"id": 1,
     "name": "Quick Start with Java"},
    {"id":,
     "name": "Reactive Web with Spring Boot"},
    {"id": 3,
     "name": ... and more!"}
]

这是我的代码(减去进口):

@Data
@Document
public class Chapter {

    @Id
    private String id;
    private String name;

    public Chapter(String name) {
        this.name = name;
    }
}


public interface ChapterRepository extends ReactiveCrudRepository<Chapter, String>{
}

@Configuration
public class LoadDatabase {

@Bean
CommandLineRunner init(ChapterRepository repository) {
    return args -> {
        Flux.just(
                new Chapter("Quick Start with Java"),
                new Chapter("Reactive Web with Spring Boot"),
                new Chapter("... and more!"))
        .flatMap(repository::save)
        .subscribe(System.out::println);
        };
    }
}

@RestController
public class ChapterController {

    private final ChapterRepository repository;

    public ChapterController(ChapterRepository repository) {
        this.repository = repository;
    }

    @GetMapping("/chapters")
    public Flux<Chapter> listing() {
        return repository.findAll();
    }

}

我的代码有问题吗？

附加信息

如下面的评论所述,我有一点发展.以前我只尝试在我的IDE中运行它.我刚从终端用java -jar build/libs/learning-spring-boot-0.0.1-SNAPSHOT.jar运行它,我得到了正确的响应.适用于失眠,邮差,浏览器和卷曲.这让我可以继续我的工作,但我很乐意为我的IDE解决这个问题.我正在使用Eclipse的Spring Tool套件.

我注意到的一件事是,当我在STS中启动服务器时,控制台输出完成了:

2018-09-09 09:54:50.646  INFO 12073 --- [ntLoopGroup-2-3] org.mongodb.driver.connection            : Opened connection [connectionId{localValue:4, serverValue:31}] to localhost:27017
2018-09-09 09:54:50.647  INFO 12073 --- [ntLoopGroup-2-2] org.mongodb.driver.connection            : Opened connection [connectionId{localValue:3, serverValue:30}] to localhost:27017
2018-09-09 09:54:50.649  INFO 12073 --- [ntLoopGroup-2-4] org.mongodb.driver.connection            : Opened connection [connectionId{localValue:5, serverValue:32}] to localhost:27017
    com.greglturnquist.learningspringboot.learningspringboot.Chapter@c56c194
    com.greglturnquist.learningspringboot.learningspringboot.Chapter@795759ac
    com.greglturnquist.learningspringboot.learningspringboot.Chapter@76e125f2

但是当在终端中运行时,我可以看到书名:

2018-09-09 09:52:42.768  INFO 12058 --- [ntLoopGroup-2-2] org.mongodb.driver.connection            : Opened connection [connectionId{localValue:3, serverValue:25}] to localhost:27017
2018-09-09 09:52:42.789  INFO 12058 --- [ntLoopGroup-2-3] org.mongodb.driver.connection            : Opened connection [connectionId{localValue:4, serverValue:26}] to localhost:27017
2018-09-09 09:52:42.791  INFO 12058 --- [ntLoopGroup-2-4] org.mongodb.driver.connection            : Opened connection [connectionId{localValue:5, serverValue:27}] to localhost:27017
Chapter(id=5b94df5ac0b4b02f1af43f43, name=Quick Start with Java)
Chapter(id=5b94df5ac0b4b02f1af43f44, name=Reactive Web with Spring Boot)
Chapter(id=5b94df5ac0b4b02f1af43f45, name=...and more!)

Answer 1

我有同样的问题,对我来说,我添加以确保我的IDE启用了Lombok注释处理(我正在使用IntelliJ Ultimate).启用此功能并重新启动我的应用程序时,我开始按预期查看数据,而不是清空JSON数组.

Answer 2

如前所述在此页面,并适用于你的使用情况:

答案是肯定的.Flux<Chapter>代表一个流Chapters.但是,默认情况下,它将生成一个JSON数组,因为如果将一个单独的JSON对象流发送到浏览器,那么它将不是一个有效的JSON文档.除了使用Server-Sent-Events或WebSocket之外,浏览器客户端无法使用流.

但是,非浏览器客户端可以通过将Accept标头设置为来请求JSON流application/stream+json,并且响应将是类似于Server-Sent-Events的JSON流,但没有额外的格式:

因此,在您的情况下,您在浏览器中请求结果.如果你想添加适当的accept header,application/stream+json你会得到想要的输出.