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我目前正在尝试与 Microsoft SQL Server 建立数据库连接。不幸的是，我不明白为什么它不起作用。不幸的是，错误消息不能给我准确的信息。看起来我的代码甚至没有尝试连接到数据库。

我的开胃菜：

@SpringBootApplication
public class R2Dbc3Application {

public static void main(String[] args) {
    SpringApplication.run(R2Dbc3Application.class, args);
}

}

数据库配置：

    package com.example.config;

import io.r2dbc.mssql.MssqlConnectionConfiguration;
import io.r2dbc.mssql.MssqlConnectionFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.r2dbc.config.AbstractR2dbcConfiguration;
import org.springframework.data.r2dbc.repository.config.EnableR2dbcRepositories;

@Configuration
@EnableR2dbcRepositories("com.example.repository")
public class DatabaseConfiguration extends AbstractR2dbcConfiguration {

    private final Logger log = LoggerFactory.getLogger(DatabaseConfiguration.class);

    @Value("${spring.data.mssql.host}")
    private String host;

    @Value("${spring.data.mssql.database}")
    private String database;

    @Value("${spring.data.mssql.username}")
    private String username;

    @Value("${spring.data.mssql.password}")
    private String password;



    @Bean
    @Override
    public MssqlConnectionFactory connectionFactory() {

        System.out.println("Connecting to database" +  host);
        return new MssqlConnectionFactory(MssqlConnectionConfiguration.builder()
                .host(host)
                .port(1453)
                .database(database)
                .username(username)
                .password(password)
                .build());
    }
}

我的数据库初始化器：

package com.example.config;

import com.example.domain.Person;
import com.example.repository.PersonRepository;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;

@Component
public class DatabaseInitializer {

    private final Logger log = LoggerFactory.getLogger(DatabaseInitializer.class);

    @Autowired
    PersonRepository personRepository;

    public DatabaseInitializer(PersonRepository personRepository) {
        this.personRepository = personRepository;
    }

    @PostConstruct
    public void init() {
        log.info("Initializing database if necessary");
        personRepository.findAll().count().subscribe(count -> {
            if (count == 0) {
                log.info("Database is empty, inserting sample data");
                createPerson("Josh", "Long", "Pivotal");
                createPerson("Julien", "Dubois", "Microsoft");
            } else {
                log.info("Database is already initialized");
            }
        });
    }

    private void createPerson(String firstName, String lastName, String company) {
        Person person = new Person();
        person.setFirstName(firstName);
        person.setLastName(lastName);
        person.setCompany(company);
        personRepository.save(person).log().subscribe();
    }
}

人.Java：

包 com.example.domain；

导入 org.springframework.data.annotation.Id；导入 org.springframework.data.relational.core.mapping.Table；

@Table("person") 公共类人 {

@Id
private Long id;

private String firstName;

private String lastName;

private String company;

和 getter/setter

我的人存储库

package com.example.repository;

import com.example.domain.Person;
import org.springframework.data.repository.reactive.ReactiveCrudRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface PersonRepository extends ReactiveCrudRepository<Person, Long> {
}

我的控制器：

package com.example.web;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.example.domain.Person;
import com.example.repository.PersonRepository;

import reactor.core.publisher.Flux;

@RestController
@RequestMapping("/")
public class PersonController {

    private final PersonRepository personRepository;

    public PersonController(PersonRepository personRepository) {
        this.personRepository = personRepository;
    }

    @GetMapping("/persons")
    public Flux<Person> list() {
        return personRepository.findAll();
    }


}

我的绒球：

<?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>2.2.6.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>R2DBC2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>R2DBC2</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
        <!-- see https://github.com/r2dbc/r2dbc-mssql/issues/77 -->
        <dependency>
            <groupId>io.projectreactor</groupId>
            <artifactId>reactor-core</artifactId>
        </dependency>

        <dependency>
            <groupId>io.r2dbc</groupId>
            <artifactId>r2dbc-mssql</artifactId>
            <version>1.0.0.M7</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-r2dbc</artifactId>
            <version>1.0.0.gh-151-SNAPSHOT</version>
        </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>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
    </dependencies>

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

    <repositories>
        <repository>
            <id>spring-libs-snapshot</id>
            <url>https://repo.spring.io/libs-snapshot</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
        </pluginRepository>
    </pluginRepositories>


</project>

错误信息：

This application has no configured error view, so you are seeing this as a fallback.

Tue May 19 12:23:33 CEST 2020
[58026f55-7] There was an unexpected error (type=Not Found, status=404).
org.springframework.web.server.ResponseStatusException: 404 NOT_FOUND
    at org.springframework.web.reactive.resource.ResourceWebHandler.lambda$handle$0(ResourceWebHandler.java:325)
    Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
    |_ checkpoint ⇢ HTTP GET "/persons" [ExceptionHandlingWebHandler]
Stack trace:
        at org.springframework.web.reactive.resource.ResourceWebHandler.lambda$handle$0(ResourceWebHandler.java:325)
        at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:44)
        at reactor.core.publisher.Mono.subscribe(Mono.java:4210)
        at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
        at reactor.core.publisher.MonoFlatMap$FlatMapMain.onComplete(MonoFlatMap.java:174)
        at reactor.core.publisher.MonoNext$NextSubscriber.onComplete(MonoNext.java:96)
        at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:359)
        at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:21
4

1 回答 1

1

org.springframework.web.server.ResponseStatusException: 404 NOT_FOUND

@GetMapping这意味着没有命中端点映射。请记住，路径在类级别与定义的映射连接，然后在方法级别，当前端点看起来像：

localhost:8080//persons

这是不正确的。

只要是没有进一步映射的根，只要它在路径中添加另一个“层”或“子路径” @RestController，就不要包含该字符。"/"正确的用法是@RequestMapping("/endpoint-name"). 在您的情况下，您不需要额外的“子路径”，因此省略注释：

@RestController
public class PersonController { ... }

不幸的是，我找不到任何参考资料来支持我的说法。

于 2020-05-19T10:44:03.353 回答