Java RequestMapping案例怎么用

Java @RequestMapping 使用案例详解

@RequestMapping 是 Spring MVC 中用于映射 HTTP 请求到控制器方法的注解。

基础配置示例

@RestController
@RequestMapping("/api")
public class UserController {
    // 映射 GET 请求
    @RequestMapping(value = "/users", method = RequestMethod.GET)
    public List<User> getAllUsers() {
        return userService.findAll();
    }
    // 使用简化注解（等价于上面的写法）
    @GetMapping("/users")
    public List<User> getAllUsers2() {
        return userService.findAll();
    }
}

完整的 CRUD 案例

@RestController
@RequestMapping("/api/users")
public class UserController {
    @Autowired
    private UserService userService;
    // 查询所有用户 - GET
    @GetMapping
    public List<User> list() {
        return userService.findAll();
    }
    // 根据ID查询 - GET
    @GetMapping("/{id}")
    public User getById(@PathVariable Long id) {
        return userService.findById(id);
    }
    // 创建用户 - POST
    @PostMapping
    public User create(@RequestBody User user) {
        return userService.save(user);
    }
    // 更新用户 - PUT
    @PutMapping("/{id}")
    public User update(@PathVariable Long id, @RequestBody User user) {
        user.setId(id);
        return userService.update(user);
    }
    // 删除用户 - DELETE
    @DeleteMapping("/{id}")
    public void delete(@PathVariable Long id) {
        userService.deleteById(id);
    }
}

路径参数使用

@RestController
@RequestMapping("/api")
public class ProductController {
    // 单个路径参数
    @GetMapping("/products/{id}")
    public Product getProduct(@PathVariable Long id) {
        return productService.findById(id);
    }
    // 多个路径参数
    @GetMapping("/categories/{categoryId}/products/{productId}")
    public Product getProductByCategory(
            @PathVariable Long categoryId, 
            @PathVariable Long productId) {
        return productService.findByCategoryAndId(categoryId, productId);
    }
}

请求参数处理

@RestController
@RequestMapping("/api")
public class SearchController {
    // 必需参数
    @GetMapping("/search")
    public List<Product> search(
            @RequestParam String keyword,
            @RequestParam(defaultValue = "1") int page,
            @RequestParam(defaultValue = "20") int size) {
        return searchService.search(keyword, page, size);
    }
    // 可选参数
    @GetMapping("/products")
    public List<Product> filter(
            @RequestParam(required = false) String category,
            @RequestParam(required = false) Double minPrice,
            @RequestParam(required = false) Double maxPrice) {
        return productService.filter(category, minPrice, maxPrice);
    }
}

请求映射组合使用

@RestController
public class MultiPathController {
    // 映射多个路径
    @GetMapping({"/api/users", "/api/customers"})
    public List<User> getUsers() {
        return userService.findAll();
    }
    // 映射多个请求方法
    @RequestMapping(value = "/data", method = {RequestMethod.GET, RequestMethod.POST})
    public String handleData() {
        return "Handles both GET and POST";
    }
    // 使用请求头过滤
    @GetMapping(value = "/api/data", headers = "content-type=application/json")
    public String handleJsonData() {
        return "Only handles JSON content type";
    }
}

综合实战案例

@RestController
@RequestMapping("/api/v1")
public class OrderController {
    private final OrderService orderService;
    public OrderController(OrderService orderService) {
        this.orderService = orderService;
    }
    // 创建订单
    @PostMapping("/orders")
    public ResponseEntity<Order> createOrder(@RequestBody @Valid OrderRequest request) {
        Order order = orderService.createOrder(request);
        return ResponseEntity.status(HttpStatus.CREATED).body(order);
    }
    // 查询订单列表（带分页）
    @GetMapping("/orders")
    public ResponseEntity<Page<Order>> listOrders(
            @RequestParam(defaultValue = "0") int page,
            @RequestParam(defaultValue = "20") int size,
            @RequestParam(required = false) String status,
            @RequestParam(required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate startDate,
            @RequestParam(required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate endDate) {
        Pageable pageable = PageRequest.of(page, size);
        Page<Order> orders = orderService.findOrders(status, startDate, endDate, pageable);
        return ResponseEntity.ok(orders);
    }
    // 获取订单详情
    @GetMapping("/orders/{orderId}")
    public ResponseEntity<OrderDetail> getOrderDetail(@PathVariable Long orderId) {
        OrderDetail detail = orderService.getOrderDetail(orderId);
        return ResponseEntity.ok(detail);
    }
    // 更新订单状态
    @PatchMapping("/orders/{orderId}/status")
    public ResponseEntity<Order> updateOrderStatus(
            @PathVariable Long orderId, 
            @RequestBody @Valid StatusUpdateRequest request) {
        Order order = orderService.updateStatus(orderId, request.getStatus());
        return ResponseEntity.ok(order);
    }
    // 取消订单
    @DeleteMapping("/orders/{orderId}")
    public ResponseEntity<Void> cancelOrder(@PathVariable Long orderId) {
        orderService.cancelOrder(orderId);
        return ResponseEntity.noContent().build();
    }
}

配置类示例

@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.example.controller")
public class WebConfig implements WebMvcConfigurer {
    @Override
    public void configurePathMatch(PathMatchConfigurer configurer) {
        // 设置路径匹配后缀
        configurer.setUseSuffixPatternMatch(false);
    }
}

1. 方法级别注解：@GetMapping、@PostMapping、@PutMapping、@DeleteMapping、@PatchMapping 是 @RequestMapping 的简化版本
2. 路径变量：使用 定义路径变量，配合 @PathVariable 获取
3. 请求参数：使用 @RequestParam 获取查询参数
4. 请求体：使用 @RequestBody 获取 POST/PUT 请求体
5. 参数验证：配合 @Valid 或 @Validated 进行参数校验

这样你就可以根据实际需求灵活使用 @RequestMapping 及其衍生注解来构建 RESTful API 了。