调用 save() 时 JpaRepository 为空

问题描述 投票：0回答：2

我正在使用 SpringBoot 和 maven 实现一个简单的 REST api，其中一部分包括从 Web 服务器读取响应并将其保存在 mySql DB 中。我正在尝试使用对象 Response 的 JpaRepository 将响应保存到 de DB 中，但由于某种原因，存储库为空。我发现另一篇文章，问题似乎出在控制器中，但我无法弄清楚为什么以及我的错误在哪里

我尝试在 forst 服务中直接注入存储库，而不是在 loadDBService 中调用 save() 函数，但它也不起作用

我的错误：无法调用“com.baeldung.api.repositories.ResponseRepository.save(Object)”，因为“this.responseRepository”为空

我的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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>provaYaml</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>19</maven.compiler.source>
        <maven.compiler.target>19</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

        <java.version>1.8</java.version>
        <maven.compiler.source>${java.version}</maven.compiler.source>
        <maven.compiler.target>${java.version}</maven.compiler.target>
        <gson-fire-version>1.9.0</gson-fire-version>
        <okhttp-version>4.11.0</okhttp-version>
        <gson-version>2.10.1</gson-version>
        <commons-lang3-version>3.14.0</commons-lang3-version>
        <jackson-databind-nullable-version>0.2.6</jackson-databind-nullable-version>
        <jakarta-annotation-version>1.3.5</jakarta-annotation-version>
        <junit-version>5.10.0</junit-version>
        <junit-platform-runner.version>1.10.0</junit-platform-runner.version>
        <javax.ws.rs-api-version>2.1.1</javax.ws.rs-api-version>
        <jsr311-api-version>1.1.1</jsr311-api-version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <spotless.version>2.43.0</spotless.version>
    </properties>


      <dependencies>
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-starter-web</artifactId>
              <version>2.4.4</version>
          </dependency>
          <dependency>
              <groupId>org.springframework.data</groupId>
              <artifactId>spring-data-jpa</artifactId>
              <version>2.4.6</version>
          </dependency>
          <dependency>
              <groupId>org.openapitools</groupId>
              <artifactId>jackson-databind-nullable</artifactId>
              <version>0.2.1</version>
          </dependency>
          <dependency>
              <groupId>org.springdoc</groupId>
              <artifactId>springdoc-openapi-ui</artifactId>
              <version>1.7.0</version>
          </dependency>
          <dependency>
              <groupId>com.google.code.findbugs</groupId>
              <artifactId>jsr305</artifactId>
              <version>3.0.2</version>
          </dependency>
          <dependency>
              <groupId>com.squareup.okhttp3</groupId>
              <artifactId>okhttp</artifactId>
              <version>${okhttp-version}</version>
          </dependency>
          <dependency>
              <groupId>com.squareup.okhttp3</groupId>
              <artifactId>logging-interceptor</artifactId>
              <version>${okhttp-version}</version>
          </dependency>
          <dependency>
              <groupId>com.google.code.gson</groupId>
              <artifactId>gson</artifactId>
              <version>${gson-version}</version>
          </dependency>
          <dependency>
              <groupId>io.gsonfire</groupId>
              <artifactId>gson-fire</artifactId>
              <version>${gson-fire-version}</version>
          </dependency>
          <dependency>
              <groupId>org.apache.commons</groupId>
              <artifactId>commons-lang3</artifactId>
              <version>${commons-lang3-version}</version>
          </dependency>
          <dependency>
              <groupId>jakarta.annotation</groupId>
              <artifactId>jakarta.annotation-api</artifactId>
              <version>${jakarta-annotation-version}</version>
              <scope>provided</scope>
          </dependency>
          <dependency>
              <groupId>org.openapitools</groupId>
              <artifactId>jackson-databind-nullable</artifactId>
              <version>${jackson-databind-nullable-version}</version>
          </dependency>
          <dependency>
              <groupId>javax.ws.rs</groupId>
              <artifactId>jsr311-api</artifactId>
              <version>${jsr311-api-version}</version>
          </dependency>
          <dependency>
              <groupId>javax.ws.rs</groupId>
              <artifactId>javax.ws.rs-api</artifactId>
              <version>${javax.ws.rs-api-version}</version>
          </dependency>
          <!-- test dependencies -->
          <dependency>
              <groupId>org.junit.jupiter</groupId>
              <artifactId>junit-jupiter-engine</artifactId>
              <version>${junit-version}</version>
              <scope>test</scope>
          </dependency>
          <dependency>
              <groupId>org.junit.platform</groupId>
              <artifactId>junit-platform-runner</artifactId>
              <version>${junit-platform-runner.version}</version>
              <scope>test</scope>
          </dependency>
          <dependency>
              <groupId>javax.annotation</groupId>
              <artifactId>javax.annotation-api</artifactId>
              <version>1.3.2</version>
          </dependency>
          <dependency>
              <groupId>mysql</groupId>
              <artifactId>mysql-connector-java</artifactId>
              <version>8.0.33</version>
          </dependency>
          <dependency>
              <groupId>jakarta.servlet</groupId>
              <artifactId>jakarta.servlet-api</artifactId>
              <version>6.1.0-M2</version>
              <scope>provided</scope>
          </dependency>
          <dependency>
              <groupId>com.google.code.gson</groupId>
              <artifactId>gson</artifactId>
              <version>2.10.1</version>
          </dependency>
          <dependency>
              <groupId>org.hibernate</groupId>
              <artifactId>hibernate-core</artifactId>
              <version>6.5.0.Final</version>
          </dependency>
          <dependency>
              <groupId>log4j</groupId>
              <artifactId>log4j</artifactId>
              <version>1.2.17</version>
          </dependency>
      </dependencies>


    <build>
        <plugins>
            <plugin>
                <groupId>org.openapitools</groupId>
                <artifactId>openapi-generator-maven-plugin</artifactId>
                <version>7.1.0</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                        <configuration>
                            <inputSpec>
                                ${project.basedir}/src/main/resources/v0.1.yaml
                            </inputSpec>
                            <generatorName>spring</generatorName>
                            <apiPackage>com.baeldung.openapi.api</apiPackage>
                            <modelPackage>com.baeldung.openapi.model</modelPackage>
                            <supportingFilesToGenerate>
                                ApiUtil.java
                            </supportingFilesToGenerate>
                            <configOptions>
                                <delegatePattern>true</delegatePattern>
                            </configOptions>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

我的控制器：

package com.baeldung.api.controller;


import com.baeldung.api.service.ForecastApiDelegate;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.annotation.Generated;
import java.util.Optional;

@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", date = "2024-05-02T13:05:10.503984100+02:00[Europe/Rome]")
@Controller
@RequestMapping("${openapi.meteo.base-path:}")
public class ForecastApiController implements ForecastApi {

    private final ForecastApiDelegate delegate;

    public ForecastApiController(@Autowired(required = false) ForecastApiDelegate delegate) {
        this.delegate = Optional.ofNullable(delegate).orElse(new ForecastApiDelegate() {});
    }

    @Override
    public ForecastApiDelegate getDelegate() {
        return delegate;
    }

}

我的预测GetService

package com.baeldung.api.service;

import com.baeldung.api.model.Response;
import com.baeldung.api.repositories.ResponseRepository;
import com.baeldung.openapi.api.ForecastApiDelegate;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

@Service
public class ForecastGetService implements ForecastApiDelegate {
    private Logger log = LogManager.getLogger(ForecastGetService.class);

    @Override
    public  ResponseEntity<String> forecastGet(Float latitude, Float longitude, String hourly) {
        try {

            return new ResponseEntity<>(getData(latitude, longitude, hourly), HttpStatus.OK);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public String getData(Float latitude, Float longitude, String hourly) throws Exception {
        log.trace("getData");
        LoadDBService loadDBService = new LoadDBService();
        URL url = new URL("https://api.open-meteo.com/v1/forecast?latitude="+ latitude +"&longitude=" + longitude+ "&hourly=" + hourly);
        HttpURLConnection con = (HttpURLConnection) url.openConnection();
        con.setRequestMethod("GET");
        

        loadDBService.createResponse(con);

        if(con.getResponseCode() < 200 || con.getResponseCode() >= 300){
            throw new RuntimeException("Risposta dal server non corretta");
        }

        BufferedReader in = new BufferedReader(
                new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuffer content = new StringBuffer();
        while ((inputLine = in.readLine()) != null) {
            content.append(inputLine);
        }
        in.close();

        return content.toString();
    }
}

我的loadDBService

package com.baeldung.api.service;


import com.baeldung.api.dtos.RequestDto;
import com.baeldung.api.dtos.ResponseDto;
import com.baeldung.api.model.Request;
import com.baeldung.api.model.Response;
import com.baeldung.api.repositories.RequestRepository;
import com.baeldung.api.repositories.ResponseRepository;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URI;
import java.net.URISyntaxException;

@Service
public class LoadDBService{

    @Autowired
    private RequestRepository requestRepository;
    @Autowired
    private ResponseRepository responseRepository;

    private Logger log = LogManager.getLogger(ForecastGetService.class);

    public LoadDBService(){
    }

    public ResponseDto extractResponse(HttpURLConnection con) throws IOException, URISyntaxException {
        String status = String.valueOf(con.getResponseCode());
        String responseMessage = con.getResponseMessage();
        URI uri = con.getURL().toURI();

        ResponseDto responseDto = new ResponseDto();
        responseDto.setUri(uri.toString());
        responseDto.setResposeMessage(responseMessage);
        responseDto.setStatusCode(status);

        return responseDto;

    }

    public void createRequest(RequestDto tmp){
        Request request = new Request(tmp);
        requestRepository.save(request);
    }

    public void createResponse(HttpURLConnection con) throws IOException, URISyntaxException {
        log.trace("metodo createResponse");
        ResponseDto tmp = extractResponse(con);
        Response response = new Response(tmp);
        responseRepository.save(response);
    }
}

我的存储库：

package com.baeldung.api.repositories;

import com.baeldung.api.model.Response;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface ResponseRepository extends JpaRepository<Response, Integer> { }

我的响应对象

package com.baeldung.api.model;

import com.baeldung.api.dtos.ResponseDto;
import jakarta.persistence.*;
import org.springframework.data.annotation.Id;

import java.io.Serializable;

@Entity
@Table (name = "web_server_response")
public class Response implements Serializable {
    @Id
    @GeneratedValue (strategy = GenerationType.AUTO)
    private int response_id;
    private String resposeMessage;
    private String statusCode;
    private String uri;

    public Response() {}


    public Response(int response_id, String resposeMessage, String statusCode, String uri) {
        this.response_id = response_id;
        this.resposeMessage = resposeMessage;
        this.statusCode = statusCode;
        this.uri = uri;
    }

    public Response(ResponseDto responseDto){
        this.uri = responseDto.getUri();
        this.resposeMessage = responseDto.getResposeMessage();
        this.statusCode = responseDto.getStatusCode();
    }

    public int getResponse_id() {
        return response_id;
    }

    public void setResponse_id(int response_id) {
        this.response_id = response_id;
    }

    public String getResposeMessage() {
        return resposeMessage;
    }

    public void setResposeMessage(String resposeMessage) {
        this.resposeMessage = resposeMessage;
    }

    public String getStatusCode() {
        return statusCode;
    }

    public void setStatusCode(String statusCode) {
        this.statusCode = statusCode;
    }

    public String getUri() {
        return uri;
    }

    public void setUri(String uri) {
        this.uri = uri;
    }
}

我的 hibernate.cfg.xml 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "https://hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <!-- Database connection properties - Driver, URL, user, password -->
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost/requests</property>
        <property name="hibernate.connection.username">test</property>
        <property name="hibernate.connection.password">test123</property>

        <!-- Outputs the SQL queries, should be disabled in Production -->
        <property name="hibernate.show_sql">true</property>

        <!-- Dialect is required to let Hibernate know the Database Type, MySQL, Oracle
            Hibernate 4 automatically figure out Dialect from Database Connection Metadata -->
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

        <!-- mapping file, we can use Bean annotations too -->
        <mapping class="com.baeldung.api.model.Response" />
        <mapping class="com.baeldung.api.model.Request" />
    </session-factory>
</hibernate-configuration>
java spring-boot hibernate spring-data-jpa repository
2个回答
0
投票

您是否尝试添加注释@EnableJpaRepositories？ 它会警告 Spring Data 它需要寻找存储库。

来源：https://www.baeldung.com/spring-data-annotations

0
投票

您正在 

LoadDBService loadDBService = new LoadDBService();
类中执行 
ForecastGetService
，而不是使用 Spring 和 
@Autowired
来注入它。如果您使用 
LoadDBService
创建 
new
，则 Spring 不会注入它的 
@Autowired
字段。

删除 

new LoadDBService()
行并将另一行添加到 
ForecastGetService
:

@Autowired
private LoadDBService loadDBService;
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