java spring Boot 不返回基于id的对象

ep6jt1vc  于 2023-06-28  发布在  Java
关注(0)|答案(4)|浏览(116)

我试图找到一个特定的国家的id，但我得到一个错误，当我测试它的 Postman 。我是新的Spring Boot ，我发现国家的id是被表示为一个bigint，而不是一个长，我在我的实体类，我不知道这是否是原因，我得到的错误。
这是我的代码

package com.elijahukeme.PropertiesManagementSystem.model;

import com.fasterxml.jackson.annotation.JsonIdentityInfo;
import com.fasterxml.jackson.annotation.ObjectIdGenerators;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import javax.persistence.*;

@Entity
@Data
@NoArgsConstructor
@AllArgsConstructor
@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class)
public class Country {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String code;
    private String capital;
    private String description;
    private String nationality;
    private String continent;
}

我的控制器

package com.elijahukeme.PropertiesManagementSystem.controller;

import com.elijahukeme.PropertiesManagementSystem.model.Country;
import com.elijahukeme.PropertiesManagementSystem.services.CountryService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
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.ResponseBody;

import java.util.List;
import java.util.Optional;

@Controller
public class CountryController {
    @Autowired
    private CountryService countryService;

    
    @GetMapping("/countries")
    public String getCountry(Model model){
        List<Country> countryList = countryService.getAllCountry();
        model.addAttribute("countries",countryList);

        return "country";
    }
   @PostMapping("/countries/addNew")
    public String saveInfo(Country country){
        countryService.saveCountryInfo(country);
        return "redirect:/countries";
    }
    @GetMapping("/findById/{id}")
    //@ResponseBody
    public Optional<Country> getCountryById(@PathVariable("id") Long countryId){ //Bind PathVariable id to id
        return countryService.getCountryById(countryId);
    }
}

服务

package com.elijahukeme.PropertiesManagementSystem.services;

import com.elijahukeme.PropertiesManagementSystem.model.Country;

import com.elijahukeme.PropertiesManagementSystem.repository.CountryRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Optional;

@Service
public class CountryService {

    @Autowired
    private CountryRepository countryRepository;

    public List<Country> getAllCountry() {
        return countryRepository.findAll();
    }
    public void saveCountryInfo(Country country){
        countryRepository.save(country);
    }
    
    public Optional<Country> getCountryById(Long id){

        return countryRepository.findById(id);
    }
}

仓库

package com.elijahukeme.PropertiesManagementSystem.repository;

import com.elijahukeme.PropertiesManagementSystem.model.Country;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface CountryRepository extends JpaRepository<Country,Long> {
}

这里是我从 Postman 得到的错误，当我传递一个特定的id检查，注意，国家与id 2存在于我的数据库中，但我不知道为什么它不返回它。就像我前面说的，国家的id是存储在数据库中的bigint而不是长

"timestamp": "2022-05-22T02:59:30.551+00:00",
    "status": 500,
    "error": "Internal Server Error",
    "path": "/findById/2"

下面是我的堆栈跟踪中的错误

org.thymeleaf.exceptions.TemplateInputException: Error resolving template [findById/2], template might not exist or might not be accessible by any of the configured Template Resolvers
    at org.thymeleaf.engine.TemplateManager.resolveTemplate(TemplateManager.java:869) ~[thymeleaf-3.0.14.RELEASE.jar:3.0.14.RELEASE]
    at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:607) ~[thymeleaf-3.0.14.RELEASE.jar:3.0.14.RELEASE]
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1098) ~[thymeleaf-3.0.14.RELEASE.jar:3.0.14.RELEASE]
    at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1072) ~[thymeleaf-3.0.14.RELEASE.jar:3.0.14.RELEASE]
    at org.thymeleaf.spring5.view.ThymeleafView.renderFragment(ThymeleafView.java:366) ~[thymeleaf-spring5-3.0.14.RELEASE.jar:3.0.14.RELEASE]
    at org.thymeleaf.spring5.view.ThymeleafView.render(ThymeleafView.java:190) ~[thymeleaf-spring5-3.0.14.RELEASE.jar:3.0.14.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1401) ~[spring-webmvc-5.3.15.jar:5.3.15]
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1145) ~[spring-webmvc-5.3.15.jar:5.3.15]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1084) ~[spring-webmvc-5.3.15.jar:5.3.15]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.15.jar:5.3.15]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.15.jar:5.3.15]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.15.jar:5.3.15]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.56.jar:4.0.FR]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.15.jar:5.3.15]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.56.jar:4.0.FR]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.15.jar:5.3.15]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.15.jar:5.3.15]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:895) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1732) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.56.jar:9.0.56]
    at java.base/java.lang.Thread.run(Thread.java:832) ~[na:na]
Java

4条答案

按热度按时间
x6h2sr28

x6h2sr281#

您将控制器定义为MVC @Controller，它需要一个视图，但您返回一个对象。
将@Controller更改为@RestController，则问题应得到解决。

赞(0）分享  回复(0）举报  2023-06-28
wgeznvg7

wgeznvg72#

您需要取消注解@ResponseBody注解

@GetMapping("/findById/{id}")
@ResponseBody
public Optional<Country> getCountryById(@PathVariable("id") Long countryId){ 
  return countryService.getCountryById(countryId);
}
赞(0）分享  回复(0）举报  2023-06-28
63lcw9qa

63lcw9qa3#

您可以使用@ResponseBody或ResponseEntity
如果使用@ResponseBody：

@GetMapping("/findById/{id}")
@ResponseBody
public Optional<Country> getCountryById(@PathVariable("id") Long countryId){ //Bind PathVariable id to id
    return countryService.getCountryById(countryId);
}

如果使用ResponseEntity：

@GetMapping("/findById/{id}")
public ResponseEntity<Country> getCountryById(@PathVariable("id") Long countryId){ //Bind PathVariable id to id
    return ResponseEntity.ok(countryService.getCountryById(countryId));
}
赞(0）分享  回复(0）举报  2023-06-28
eyh26e7m

eyh26e7m4#

同样的问题是在JSON的响应体中没有得到id。我的问题通过在JPA实体中添加getter和setter方法解决了。

赞(0）分享  回复(0）举报  2023-06-28
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