spring-boot - 如何在 Spring Controller 中使用 ID（主键）搜索？

问题描述

我正在尝试通过 JpaRepositorygetOne传递密钥的主键进行搜索

我有一个模型（客户），我在其中定义了客户的详细信息。我有一个接口服务（CustomerService）和它的实现（CustomerServiceImpl，它实现了 CustomerService）。我还有一个接口存储库（CustomerRepository，它扩展了 JpaRepository。现在在我的控制器中，我将一个 id 传递给一个函数（findCustomerById）并使用 JpaRepository 从客户存储库中获取具有该 ID 的客户getOne

客户 customer=customerRepository.getOne(id);

我不断收到错误消息500 (java.lang.NullPointerException: null。我的代码似乎没问题。可能是什么问题？客户.java

package com.javadevjournal.customer;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="customer")
public class Customer {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column(name="first_name")
    private String firstName;

    @Column(name="last_name")
    private String lastName;

    @Column(name="address")
    private String address;

    public Customer() {
        super();

    }

    public Long getId() {
        return id;
    }

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

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

CustomerRepository.java：

package com.javadevjournal.customer;

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

@Repository
public interface CustomerRepository extends JpaRepository<Customer, Long>{

}

客户控制器.java：

package com.javadevjournal.customer;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.PostMapping;

import org.springframework.http.HttpHeaders;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.util.UriComponentsBuilder;
import com.javadevjournal.customer.CustomerService;

import javax.validation.Valid;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;

@RestController
public class CustomerController {

    @Autowired
    private CustomerService  customerService;
    private CustomerRepository customerRepository;

    @GetMapping(path = "/customers")
    public Iterable<Customer> findAll() {
        Iterable<Customer> customers = customerService.findAll();
        return customers;
    }

    // Get a Single Customer
    @GetMapping(path = "/getCustomer/{id}")
    public Customer findCustomerById(@PathVariable("id") Long id) {
        System.out.println("Am going on here...");
        System.out.println("id=="+id);
        System.out.println("fetching customers.."+id);
        Customer customer=customerRepository.getOne(id);
        System.out.println(customer);
        return customer;
    }

    // Create a new Customer
    @PostMapping("/customers")
    public Customer createCustomer(@Valid @RequestBody Customer customer) {
        return customerRepository.save(customer);
    }


}

我希望根据从邮递员（http://localhost:8080/getCustomer/1）传递的 ID 获得特定客户，但邮递员给了我以下错误消息：

此应用程序没有显式映射 /error，因此您将其视为后备。Tue Jun 25 11:58:47 EAT 2019 出现意外错误（类型=内部服务器错误，状态=500）。在 sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java: 62) 在 sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 在 java.lang.reflect.Method.invoke(Method.java:498) 在 org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod .java:190) 在 org.springframework.web.method.support.InvocableHandlerMethod。

标签： spring-boot

spring-boot - 如何在 Spring Controller 中使用 ID（主键）搜索？

问题描述

解决方案

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