新bing之chat使用体验：Java语言的CRUD操作

今天，我的新bing使用在等待多天的watinglist，申请终于生效了。作为一个Java老鸟，第一把肯定是要让它给我撸个入门级代码CRUD啦，不说啦，上图。

我问（以下简称 I ）：Write code get crud example in java program

 

Okay, I will show you an example code for each step. Please note that this is just a sample code and you may need to modify it according to your requirements.

Step 1: Generate a starter project with Spring Web dependency.

You can use https://start.spring.io/ to generate a starter project with Spring Web dependency. You need to set the Java version to 11 and add Spring Web as a dependency. Then click on Generate button to download a zip file containing the project.

Step 2: Create an entity class with JPA annotations .

You need to create a class that represents your data model. For example, if you want to store employee details, you can create a class called Employee with fields like id, name, email, salary etc. You also need to add JPA annotations like @Entity, @Id, @GeneratedValue etc. to mark this class as an entity and map it to a database table.

Here is an example code for Employee class:

 

Okay, I will show you the next step.

Step 4: Create a controller class that handles HTTP requests and calls repository methods.

You need to create a class that is annotated with @RestController and @RequestMapping to define the base URL for your API. This class will have methods that are annotated with @GetMapping, @PostMapping, @PutMapping, @DeleteMapping etc. to handle different HTTP requests and perform CRUD operations using repository methods. You also need to use @RequestBody and @PathVariable annotations to get data from request body and URL path variables.

Here is an example code for EmployeeController class:

package com.example.demo.controller;

import com.example.demo.model.Employee;
import com.example.demo.repository.EmployeeRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

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

@RestController
@RequestMapping("/employees")
public class EmployeeController {

    @Autowired
    private EmployeeRepository employeeRepository;

    // Get all employees
    @GetMapping
    public List<Employee> getAllEmployees() {
        return (List<Employee>) employeeRepository.findAll();
    }

    // Get employee by id
    @GetMapping("/{id}")
    public ResponseEntity<Employee> getEmployeeById(@PathVariable Long id) {
        Optional<Employee> employee = employeeRepository.findById(id);
        if (employee.isPresent()) {
            return ResponseEntity.ok(employee.get());
        } else {
            return ResponseEntity.notFound().build();
        }
    }

    // Create new employee
    @PostMapping
    public Employee createEmployee(@RequestBody Employee employee) {
        return employeeRepository.save(employee);
    }

    // Update employee by id
    @PutMapping("/{id}")
    public ResponseEntity<Employee> updateEmployee(@PathVariable Long id, @RequestBody Employee updatedEmployee) {
        Optional<Employee> employee = employeeRepository.findById(id);
        if (employee.isPresent()) {
            Employee currentEmployee = employee.get();
            currentEmployee.setName(updatedEmployee.getName());
            currentEmployee.setEmail(updatedEmployee.getEmail());
            currentEmployee.setSalary(updatedEmployee.getSalary());
            return ResponseEntity.ok(employeeRepository.save(currentEmployee));
        } else {
            return ResponseEntity.notFound().build();
        }
    }

    // Delete employee by id
    @DeleteMapping("/{id}")
    public ResponseEntity<Void> deleteEmployee(@PathVariable Long id) {
        Optional<Employee> employee = employeeRepository.findById(id);
        if (employee.isPresent()) {
            employeeRepository.deleteById(id);
            return ResponseEntity.ok().build();
        } else {
            return ResponseEntity.notFound().build();
        }
    }
}
```

Do you want me to show you the last step?

Source: Conversation with Bing, 2023/2/23(1) Spring Boot JPA CRUD Example (2023) - TechGeekNext. https://www.techgeeknext.com/spring-boot/spring-boot-jpa-crud-example Accessed 2023/2/23.
(2) Spring Boot - CrudRepository with Example - GeeksforGeeks. https://www.geeksforgeeks.org/spring-boot-crudrepository-with-example/ Accessed 2023/2/23.
(3) Spring Boot - CRUD Operations - GeeksforGeeks. https://www.geeksforgeeks.org/spring-boot-crud-operations/ Accessed 2023/2/23.
(4) Spring Boot CRUD Operations - javatpoint. https://www.javatpoint.com/spring-boot-crud-operations Accessed 2023/2/23.
(5) Spring Boot and Java Tutorial: Build a CRUD API - Auth0. https://auth0.com/blog/spring-boot-java-tutorial-build-a-crud-api/ Accessed 2023/2/23.