Spring Boot + JPA + MySQL在检索和存储数据时遇到500错误内部服务器

如何解决Spring Boot + JPA + MySQL在检索和存储数据时遇到500错误内部服务器

我正在创建Spring API，但是在创建GET和POST请求时会抛出500个HTTP状态代码，但是当我在MysqL 数据库中签入时，它正在存储数据

application.properties

# DataSource settings: set here your own configurations for the database connection.
# In this example we have "javatechie" as database name and
# "root" as username and password.
spring.datasource.driver-class-name=com.MysqL.cj.jdbc.Driver
spring.datasource.url=jdbc:MysqL://localhost:3306/javatechie
spring.datasource.username=root
spring.datasource.password=root
# Show or not log for each sql query
spring.jpa.show-sql=true
# Hibernate ddl auto (create,create-drop,update)
spring.jpa.hibernate.ddl-auto=update
# The sql dialect makes Hibernate generate better sql for the chosen database
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MysqL5Dialect

Product.java

@Data
@AllArgsConstructor
@NoArgsConstructor
@Entity
public class Product {

    @Id
    @GeneratedValue
    private int id;
    private String name;
    private int quantity;
    private double price;
}

ProductController.java

@Controller
public class ProductController {
    @Autowired
    private ProductService productService;

    @PostMapping("/addProduct")
    public Product addProduct(@RequestBody Product product){
        return productService.saveProduct(product);
    }

    @PostMapping("/addProducts")
    public List<Product> addProducts(@RequestBody List<Product> product){
        return productService.saveProducts(product);
    }

    @GetMapping("/products")
    public List<Product> findAllProducts(){
        return productService.getProducts();
    }

    @GetMapping("/product/{id}")
    public Product findProductById(@PathVariable int id){
        return productService.getProductById(id);
    }

    @GetMapping("/product/{name}")
    public Product findProductByName(@PathVariable String name){
        return productService.getProductsByName(name);
    }

    @PutMapping("/update")
    public Product updateProduct(@RequestBody Product product){
        return productService.updateProduct(product);
    }

    @DeleteMapping("/delete/{id}")
    public String deleteProduct(@PathVariable int id){
        return productService.deleteProduct(id);
    }
}

ProductService.java

@Service
public class ProductService {

    @Autowired
    private ProductRepository productRepository;

    public Product saveProduct(Product product){
        return productRepository.save(product);
    }

    public List<Product> saveProducts(List<Product> products){
        return productRepository.saveAll(products);
    }

    public List<Product> getProducts(){
        return productRepository.findAll();
    }

    public Product getProductById(int id){
        return productRepository.findById(id).orElse(null);
    }

    public Product getProductsByName(String name){
        return productRepository.findByName(name);
    }

    public String deleteProduct(int id){
        productRepository.deleteById(id);
        return "product removed !!!";
    }

    public Product updateProduct(Product product){
        return productRepository.save(product);
    }
}

注意：- 当我从邮递员发送POST请求时，它把我扔了

{
    "timestamp": "2020-09-24T20:01:15.060+00:00","status": 500,"error": "Internal Server Error","message": "","path": "/addProduct"
}

但是当我在MysqL 数据库中签入时，我通过POST请求发送的条目就在那里了

问题

为什么我会收到HTTP状态码500错误？
即使我遇到错误，然后数据又如何在数据库中存储？
如果我成功地将数据存储在数据库中，那为什么不通过GET请求呢？

错误日志

2020-09-25 09:25:50.447  INFO 12128 --- [nio-8080-exec-1] o.s.web.servlet.dispatcherServlet        : Completed initialization in 10 ms
Hibernate: select product0_.id as id1_0_,product0_.name as name2_0_,product0_.price as price3_0_,product0_.quantity as quantity4_0_ from product product0_
2020-09-25 09:25:50.613 ERROR 12128 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Circular view path [products]: would dispatch back to the current handler URL [/products] again. Check your ViewResolver setup! (Hint: This may be the result of an unspecified view,due to default view name generation.)] with root cause

javax.servlet.servletexception: Circular view path [products]: would dispatch back to the current handler URL [/products] again. Check your ViewResolver setup! (Hint: This may be the result of an unspecified view,due to default view name generation.)
    at org.springframework.web.servlet.view.InternalResourceView.prepareForRendering(InternalResourceView.java:210) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:148) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:316) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.dispatcherServlet.render(dispatcherServlet.java:1373) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.dispatcherServlet.processdispatchResult(dispatcherServlet.java:1118) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.dispatcherServlet.dodispatch(dispatcherServlet.java:1057) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.dispatcherServlet.doService(dispatcherServlet.java:943) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) ~[tomcat-embed-core-9.0.38.jar:4.0.FR]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.38.jar:4.0.FR]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.tomcat.util.net.socketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at java.base/java.lang.Thread.run(Thread.java:830) ~[na:na]

解决方法

为什么我收到HTTP状态码500错误？ =>您得到500，因为您的控制器需要视图模板（例如thymeleaf，JSP或任何其他视图引擎）
即使我遇到错误，然后数据如何在数据库中存储？ =>仅在呈现不持久数据时才有问题，这就是为什么它存储在数据库中的原因
如果我成功地将数据存储在数据库中，那为什么不通过GET请求呢？ =>因为您的GET Controller仍然需要视图模板。

如果要开发Restful API，请使用@RestController或在每个控制器端点方法上添加@ResponseBody。

顺便说一句，您不应使用Entity来处理您的请求正文。

请显示服务器日志。只有服务器响应，才能弄清楚。用try / catch包围控制器并打印异常