“状态”：Spring 引导 CRUD 中 POST 请求的 404 错误

Question

我开发了 Spring Boot CRUD 应用程序。 我连接的数据库是PostgreSQL。 @GetMapping工作正常，可以通过GET请求检索一个空的对象数组。 但是在@PostMapping中，POST 请求给出了 404 错误。

SpringRecapApplication.java

package com.example.SpringRecap;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@SpringBootApplication(exclude = SecurityAutoConfiguration.class)
//@RequestMapping("api/v1/customers")
//@EnableWebMvc
@RequestMapping(name = "api/v1/customers" ,method = RequestMethod.POST)

public class SpringRecapApplication {
    //dependency injection
    private static  CustomerRepository customerRepository;

    public SpringRecapApplication(CustomerRepository customerRepository) {
        this.customerRepository = customerRepository;
    }


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

    @GetMapping
    public List<Customer> getCustomer() {

        return customerRepository.findAll();

    }

    record NewCustomerRequest(
            String name,
            String email,
            Integer age
    ) {
        @PostMapping
        public void addCustomer(@RequestBody NewCustomerRequest newCustomerRequest) {
            Customer customer = new Customer();
            customer.setAge(newCustomerRequest.age());
            customer.setName(newCustomerRequest.name());
            customer.setEmail(newCustomerRequest.email());
            customerRepository.save(customer);
        }
    }

}

customerRepository.save(customer); 不允许使依赖注入最终。 （ private static CustomerRepository customerRepository; ）。 IDEA建议将其设置为static。但没有成功。 当我使用@RequestMapping("api/v1/customers")时，收到 405 错误。 然后我通过执行以下操作解决了该问题，

 @RequestMapping(name = "api/v1/customers" ,method = RequestMethod.POST)

CustomerRepository.java

package com.example.SpringRecap;

import org.springframework.data.jpa.repository.JpaRepository;

public interface CustomerRepository extends JpaRepository<Customer,Integer> {
}

客户.java

package com.example.SpringRecap;

import jakarta.persistence.*;

import java.util.Objects;

@Entity
public class Customer {
    @Id
    @SequenceGenerator(
            name = "customer_id_sequence",
            sequenceName = "customer_id_sequence",
            allocationSize = 1

    )
    @GeneratedValue(
            strategy = GenerationType.SEQUENCE,
            generator = "customer_id_sequence"

    )
    private Integer id;
    private String name;
    private String email;
    private Integer age;

    public Customer(Integer id, String name, String email, Integer age) {
        this.id = id;
        this.name = name;
        this.email = email;
        this.age = age;
    }

    public Customer() {

    }


    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Customer customer = (Customer) o;
        return Objects.equals(id, customer.id) && Objects.equals(name, customer.name) && Objects.equals(email, customer.email) && Objects.equals(age, customer.age);
    }

    @Override
    public int hashCode() {
        return Objects.hash(id, name, email, age);
    }

    @Override
    public String toString() {
        return "Customer{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", email='" + email + '\'' +
                ", age=" + age +
                '}';
    }
}

Postman：

如果需要更多信息来获得解决方案，请发表评论。

Answer 1

您的代码的问题是您将 POST 端点指定为 DTO 的一部分，而不是 controller 的一部分。由于您的 DTO 不是 Spring 托管 bean，因此 Spring 不会 map URL 到您的端点。 无论如何，您应该将端点移动到单独的 class 中。示例：

@RestController
@RequestMapping("api/v1/customers")
public class CustomerController {

    private final CustomerRepository customerRepository;

    public SpringRecapApplication(CustomerRepository customerRepository) {
        this.customerRepository = customerRepository;
    }

    @GetMapping
    public List<Customer> getCustomer() {
        return customerRepository.findAll();
    }
    
    @PostMapping
    public void addCustomer(@RequestBody NewCustomerRequest newCustomerRequest) {
        Customer customer = new Customer();
        customer.setAge(newCustomerRequest.age());
        customer.setName(newCustomerRequest.name());
        customer.setEmail(newCustomerRequest.email());
        customerRepository.save(customer);
    }

    // Helper classes

    record NewCustomerRequest(String name, String email, Integer age) { }

}

最好将 DTO 也移到单独的 class 中。 我建议将 DTO 放在dto package 中，将控制器放在controller package 中。

两个旁注：你不应该通过你的 API 公开你的实体。你应该使用 DTO 来处理传入和传出的数据。 查看lombok和mapstruct ，它们使这很容易。