在一列中使用“获取空值”；findById“；在JavaSpring中，尽管它存在于DB中_Java_Angular_Spring_Jpa

在一列中使用“获取空值”；findById“；在JavaSpring中，尽管它存在于DB中

java angular spring jpa

在一列中使用“获取空值”；findById“；在JavaSpring中，尽管它存在于DB中,java,angular,spring,jpa,Java,Angular,Spring,Jpa,我对JavaSpring非常陌生，有一个问题，我无法找出我缺少了什么为了简洁起见，我将把它缩短：我有一个控制器类，它有两个方法用于@GetMapping（从数据库中的患者获取信息）和@PostMapping（从该患者上传照片）在这两种方法中，在某个时刻，我通过“findById”调用数据库并填充“Patient”模型类对象该类的所有属性都已从数据库中成功检索，但该类的一个属性（getPhoto（））仅在@PostMapping方法中获取空值我错过了什么？这两种方法的代码完全相同非

我对JavaSpring非常陌生，有一个问题，我无法找出我缺少了什么

为了简洁起见，我将把它缩短：

我有一个控制器类，它有两个方法用于@GetMapping（从数据库中的患者获取信息）和@PostMapping（从该患者上传照片）
在这两种方法中，在某个时刻，我通过“findById”调用数据库并填充“Patient”模型类对象
该类的所有属性都已从数据库中成功检索，但该类的一个属性（getPhoto（））仅在@PostMapping方法中获取空值
我错过了什么？这两种方法的代码完全相同

非常感谢

控制器：

@CrossOrigin(origins="http://localhost:4200", maxAge = 3600)
@RestController
@RequestMapping({"/patients"})
public class PatientController {

    @Autowired
    IPatientService patientService;


    @GetMapping("/{id}")
    public ResponseEntity<?> listPatientId(@PathVariable("id") Integer id){

        Optional<Patient> patient=null;
        Map<String, Object> response=new HashMap<>();

        try{
            patient=patientService.findById(id);
        }catch(DataAccessException e){
            response.put("error", e.getMessage().concat(": "+e.getMostSpecificCause().toString()));
            new ResponseEntity<Map<String, Object>>(response, HttpStatus.INTERNAL_SERVER_ERROR);
        }

        System.out.println("Patient with id: "+id+" / "+patient.get().getId()+" which photo is: "+patient.get().getPhoto());

        /*Some other code*/
    }

    @PostMapping("/upload")
    public ResponseEntity<?> upload(@RequestParam("archive")MultipartFile archive, @RequestParam("id") Integer id){

        Optional<Paciente> paciente = Optional.empty();
        Map<String, Object> respuesta= new HashMap<>();

        try{
            patient=patientService.findById(id);
        }catch(DataAccessException e){
            response.put("error", e.getMessage().concat(": "+e.getMostSpecificCause().toString()));
            new ResponseEntity<Map<String, Object>>(response, HttpStatus.INTERNAL_SERVER_ERROR);
        }

        System.out.println("Patient with id: "+id+" / "+patient.get().getId()+" which photo is: "+patient.get().getPhoto());

        /*Some other code*/

    }
}

package question.controller;

import java.util.HashMap;
import java.util.Map;
import java.util.Optional;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataAccessException;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import question.repository.Patient;
import question.repository.PatientsRepository;

@CrossOrigin(origins="http://localhost:4200", maxAge = 3600)
@RestController
@RequestMapping("/patients")
public class PatientController {

    private PatientsRepository patientsRepository;

    @Autowired
    public PatientController(PatientsRepository patientsRepository) {
        this.patientsRepository = patientsRepository;
    }

    @GetMapping("/{id}")
    public ResponseEntity<?> listPatientId(@PathVariable("id") Integer id){

        Optional<Patient> patient=null;
        Map<String, Object> response=new HashMap<>();

        try{
            patient = patientsRepository.findById(id);
        }catch(DataAccessException e){
            response.put("error", e.getMessage().concat(": "+e.getMostSpecificCause().toString()));
            new ResponseEntity<Map<String, Object>>(response, HttpStatus.INTERNAL_SERVER_ERROR);
        }

        System.out.println("Patient with id: "+id+" / "+patient.get().getId()+" which photo is: "+patient.get().getPhoto());

        return ResponseEntity.ok(patient);
    }

    @PostMapping(value="/upload")
    public ResponseEntity<?> upload(@RequestParam("archive") MultipartFile archive, @RequestParam("id") Integer id){

        Optional<Patient> patient = Optional.empty();
        Map<String, Object> response = new HashMap<>();

        try{
            patient = patientsRepository.findById(id);
        }catch(DataAccessException e){
            response.put("error", e.getMessage().concat(": "+e.getMostSpecificCause().toString()));
            new ResponseEntity<Map<String, Object>>(response, HttpStatus.INTERNAL_SERVER_ERROR);
        }

        System.out.println("Patient with id: "+id+" / "+patient.get().getId()+" which photo is: "+patient.get().getPhoto());

        return ResponseEntity.ok(patient);

    }
    
}

存储库：

@Repository
public interface PatientRepository extends JpaRepository<Patient, Integer> {

    Iterable<Patient> findByNameContainingOrSurnameContaining(String name, String surname);

}

package question.repository;

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

@Repository
public interface PatientsRepository extends CrudRepository<Patient, Integer>{

}

服务：


  constructor(private http:HttpClient, private router:Router) {
    this.urlPatients='http://localhost:8080/patients';
   }

uploadPhoto(file: File, id):Observable<Patient>{

     let formData= new FormData();
    

     formData.append("archive", file);
     formData.append("id", id);
     
     return this.http.post(`${this.urlPatients}/upload`, formData).pipe(
       map((response:any)=> response.patient as Patient),
       catchError(e=>{
         console.error(e.error.mensaje);
         return throwError(e);
       })
     );

   }


构造函数（专用http:HttpClient，专用路由器：路由器）{
这是我的http://localhost:8080/patients';
}
上传照片（文件：文件，id）：可观察{
设formData=new formData（）；
formData.append（“存档”，文件）；
formData.append（“id”，id）；
返回this.http.post（`${this.urlPatients}/upload`，formData）.pipe(
map（（应答：任意）=>response.patient作为患者），
捕捉错误（e=>{
控制台错误（e.error.mensaje）；
回击投手（e）；
})
);
}

更新：

使用邮递员并向http://localhost:8080/patients/upload 在主体中发送了一个jpg文件（表单数据-“归档”）和一个id号（“id”），我成功地插入了内容，而以前在后端无法使用的方法（patient.get（）.getPhoto（））这次运行得非常好。使用相同的代码，所以我假设这是@BiteBat所说的，这是前端的问题，以及它如何调用后端的问题。

我模拟了您创建的相同环境，正如您所期望的，它对我有效，我将代码留给您来检查您的问题所在。我认为您调用POST方法是错误的。现在，我建议您不要将图像保存在关系数据库中，因为还有性能更好的替代方案，例如Google存储/本地存储或任何文件存储服务

结构：

入口点：

package question;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@SpringBootApplication
@EnableJpaRepositories
public class JulianPelayoApplication {

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

}

控制器：

@CrossOrigin(origins="http://localhost:4200", maxAge = 3600)
@RestController
@RequestMapping({"/patients"})
public class PatientController {

    @Autowired
    IPatientService patientService;


    @GetMapping("/{id}")
    public ResponseEntity<?> listPatientId(@PathVariable("id") Integer id){

        Optional<Patient> patient=null;
        Map<String, Object> response=new HashMap<>();

        try{
            patient=patientService.findById(id);
        }catch(DataAccessException e){
            response.put("error", e.getMessage().concat(": "+e.getMostSpecificCause().toString()));
            new ResponseEntity<Map<String, Object>>(response, HttpStatus.INTERNAL_SERVER_ERROR);
        }

        System.out.println("Patient with id: "+id+" / "+patient.get().getId()+" which photo is: "+patient.get().getPhoto());

        /*Some other code*/
    }

    @PostMapping("/upload")
    public ResponseEntity<?> upload(@RequestParam("archive")MultipartFile archive, @RequestParam("id") Integer id){

        Optional<Paciente> paciente = Optional.empty();
        Map<String, Object> respuesta= new HashMap<>();

        try{
            patient=patientService.findById(id);
        }catch(DataAccessException e){
            response.put("error", e.getMessage().concat(": "+e.getMostSpecificCause().toString()));
            new ResponseEntity<Map<String, Object>>(response, HttpStatus.INTERNAL_SERVER_ERROR);
        }

        System.out.println("Patient with id: "+id+" / "+patient.get().getId()+" which photo is: "+patient.get().getPhoto());

        /*Some other code*/

    }
}

package question.controller;

import java.util.HashMap;
import java.util.Map;
import java.util.Optional;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataAccessException;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import question.repository.Patient;
import question.repository.PatientsRepository;

@CrossOrigin(origins="http://localhost:4200", maxAge = 3600)
@RestController
@RequestMapping("/patients")
public class PatientController {

    private PatientsRepository patientsRepository;

    @Autowired
    public PatientController(PatientsRepository patientsRepository) {
        this.patientsRepository = patientsRepository;
    }

    @GetMapping("/{id}")
    public ResponseEntity<?> listPatientId(@PathVariable("id") Integer id){

        Optional<Patient> patient=null;
        Map<String, Object> response=new HashMap<>();

        try{
            patient = patientsRepository.findById(id);
        }catch(DataAccessException e){
            response.put("error", e.getMessage().concat(": "+e.getMostSpecificCause().toString()));
            new ResponseEntity<Map<String, Object>>(response, HttpStatus.INTERNAL_SERVER_ERROR);
        }

        System.out.println("Patient with id: "+id+" / "+patient.get().getId()+" which photo is: "+patient.get().getPhoto());

        return ResponseEntity.ok(patient);
    }

    @PostMapping(value="/upload")
    public ResponseEntity<?> upload(@RequestParam("archive") MultipartFile archive, @RequestParam("id") Integer id){

        Optional<Patient> patient = Optional.empty();
        Map<String, Object> response = new HashMap<>();

        try{
            patient = patientsRepository.findById(id);
        }catch(DataAccessException e){
            response.put("error", e.getMessage().concat(": "+e.getMostSpecificCause().toString()));
            new ResponseEntity<Map<String, Object>>(response, HttpStatus.INTERNAL_SERVER_ERROR);
        }

        System.out.println("Patient with id: "+id+" / "+patient.get().getId()+" which photo is: "+patient.get().getPhoto());

        return ResponseEntity.ok(patient);

    }
    
}

Spring.properties：

spring.datasource.url=jdbc:postgresql://localhost/test
spring.datasource.username=test
spring.datasource.password=test
spring.datasource.driver-class-name=org.postgresql.Driver
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.PostgreSQLDialect

Pom：


4.0.0
org.springframework.boot

职位
注意，您可以简单地使用@PathVariable（“id”）Patient-Patient
。但是，您是否调试了控制器并确保id的值与您期望的值相符？您在两个catch block中都错过了“return”语句谢谢您的回答。是的，我确保值id在两种方法中都是正确的。。。虽然我的示例中缺少return语句，但在实际代码中我提供了它。非常感谢您对BiteBat的回复。虽然它对我很有用，但我无法解决获取照片字符串名称的问题（patient.get（）.getPhoto（））。我会继续努力，一旦我发现我的错误，我会把它贴在这里。也谢谢你的推荐！您能告诉我们您是如何使用或调用该方法的吗？您还可以显示服务类和存储库类，这些类中也可能有错误。很抱歉@BiteBat延迟了响应。我再次编辑了我的问题，插入了存储库和服务类。以及前端（角度）中调用方法的部分。我使用了Postman，一切都很完美，所以我假设这是如您所说的，问题与Angular有关，而不是JavaSpring代码。
@Entity
@Table(name = "patients", schema = "business")
@Getter @Setter
public class Patient {

    @Id
    @Column
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer id;

    @Column
    private String photo;
    
}

spring.datasource.url=jdbc:postgresql://localhost/test
spring.datasource.username=test
spring.datasource.password=test
spring.datasource.driver-class-name=org.postgresql.Driver
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.PostgreSQLDialect

<?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>2.3.1.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <groupId>question</groupId>
    <artifactId>JulianPelayo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>JulianPelayo</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-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <scope>runtime</scope>
        </dependency>

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

    </dependencies>

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

</project>