通过Java实现一个简单的RESTful API服务案例

原创谁借莪１个温暖的怀抱￠ 2024-10-19 14:36 95阅读 0赞

以下是一个基于Java和Spring Boot框架实现的简单RESTful API服务案例。我们将创建一个"User"资源，允许增删查操作。

1. 创建一个新的Spring Boot项目。

2. 添加依赖：
```
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
```

3. 创建`User.java`模型类：
```java
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class User {

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

private String name;

// getters and setters

public Long getId() {
        return id;
    }

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

public String getName() {
        return name;
    }

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

4. 创建`UserController.java`控制器类：
```java
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/users")
public class UserController {

@Autowired
    private UserRepository userRepository;

// CRUD operations

@GetMapping
    public List<User> getAllUsers() {
        return userRepository.findAll();
    }

@PostMapping
    public User createUser(@RequestBody User user) {
        return userRepository.save(user);
    }

@PutMapping("/{id}")
    public User updateUser(@PathVariable Long id, @RequestBody User updatedUser) {
        User existingUser = userRepository.findById(id).orElse(null);
        if (existingUser != null) {
            updatedUser.setId(existingUser.getId());
            return userRepository.save(updatedUser);
        } else {
            throw new HttpStatusRuntimeException(HttpStatus.NOT_FOUND, "User with id " + id + " not found"));
        }
    }

@DeleteMapping("/{id}")
    public void deleteUser(@PathVariable Long id) {
        User user = userRepository.findById(id).orElse(null);
        if (user != null) {
            userRepository.delete(user);
        } else {
            throw new HttpStatusRuntimeException(HttpStatus.NOT_FOUND, "User with id " + id + " not found"));
        }
    }
}
```

现在，你已经创建了一个基本的RESTful API服务，可以进行用户增删查操作。你可以通过`http://localhost:8080/users`访问API，使用Postman等工具测试API功能。