java - Spring 文档中最简单的示例不起作用。“考虑在你的配置中定义一个 'xxxRepository' 类型的 bean。”

Question

我真的越来越累了。一整天我都在尝试使用 DB 对应用程序进行最简单的配置，但没有任何效果，即使我 1:1 复制教程也是如此。

https://spring.io/guides/gs/accessing-data-mysql/

从提供的包中复制所有 3 个类（MainController, UserRepository, User+ pom.xml）后，更改数据库配置application.properties，我收到以下错误：

Description:

Field userRepository in com.example.testfield.MainController required a bean of type 'com.example.testfield.UserRepository' that could not be found.

The injection point has the following annotations:
    - @org.springframework.beans.factory.annotation.Autowired(required=true)


Action:

Consider defining a bean of type 'com.example.testfield.UserRepository' in your configuration.

当我添加@EnableJpaRepositories并强制扫描时TestFieldApplication，我得到：@RepositoryUserRepository

Field userRepository in com.example.testfield.MainController required a bean named 'entityManagerFactory' that could not be found.

当我尝试以entityManager这种方式手动添加时：

@Configuration
public class ApplicationConfiguration {

    @Bean
    public DataSource getDataSource() {
        return DataSourceBuilder.create()
                                         .driverClassName("com.mysql.jdbc.Driver")
                                         .url("jdbc:mysql://localhost:3306/xxx")
                                         .username("xxx")
                                         .password("xxx")
                                         .build();
    }

    protected AbstractJpaVendorAdapter createJpaVendorAdapter() {
        final HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        return vendorAdapter;
    }

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
        LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
        factory.setJpaVendorAdapter(createJpaVendorAdapter());
        factory.setPackagesToScan("com.example.TestField.entity");
        factory.setDataSource(getDataSource());
        return factory;
    }

    @Bean
    public PlatformTransactionManager transactionManager(EntityManagerFactory entityManagerFactory){
        JpaTransactionManager txManager = new JpaTransactionManager();
        txManager.setEntityManagerFactory(entityManagerFactory);
        return txManager;
    }
}

然后我有一个问题说“找不到支持的数据源类型”。

我尝试了一切 - 用新用户创建一个新数据库，更改每个依赖项的版本，将属性放在application.properties......没有任何效果。我很沮丧，因为它是如此基本的东西，我尝试了一些教程，复制它们，但没有任何效果，难以置信！

附言。从 Intellij 插件连接时，我使用了相同的 url/user/password 来测试连接，它工作正常。

编辑：添加其他类

package com.example.testfield;

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

@SpringBootApplication
public class TestField {

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

package com.example.testfield;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface UserRepository extends CrudRepository<User, Integer> {

}

<?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>2.5.6</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>accessing-data-mysql</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>TestField</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-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.27</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

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

</project>

标签： javaspring

Answer 1

好的，最后我能够解决问题。解决方案是将 getDataSource 方法的返回类型从：

    @Bean
    public DataSource getDataSource() {
        return DataSourceBuilder.create()               
                                .url("xxx")                            
    (...)
                                .build();
    }

至：

    @Bean
    public DataSource getDataSource() {
        DriverManagerDataSource ds = new DriverManagerDataSource();
        ds.setUrl("xxx")
        (...)
        return ds;
    }

有点混乱，互联网上的大多数教程都显示第一种方式。感谢所有试图提供帮助的人！:)