为什么 Rest 控制器给出错误:"No adapter for handler"?



我想做一个spring与MongoDB交互的简单例子。我有一个产品型号:

@NoArgsConstructor
@ToString(exclude = {"id"})
public class Product {
@Id
private String id;
private String name;
private Integer price;
private LocalDateTime localDateTime;
public Product(String name, Integer price, LocalDateTime localDateTime) {
this.name = name;
this.price = price;
this.localDateTime = localDateTime;
}
}

一个简单的存储库和一个用于处理DB的服务:

public interface productRepository extends MongoRepository<Product,String> {
Product findByName(String name);
List<Product> findByPrice(Integer price);
}

服务

@AllArgsConstructor
@Service
public class productServiceImpl implements productService<Product>{
productRepository repository;
@Override
public Product saveOrUpdateProduct(Product product) {
return repository.save(product);
}
@Override
public List<Product> findAll() {
return repository.findAll();
}
@Override
public Product findByName(String name) {
return repository.findByName(name);
}
@Override
public List<Product> findByPrice(Integer price) {
return repository.findByPrice(price);
}
}

当我检查findAll的工作时,一切都很好。但当使用Rest Service时:


@RestController("/products")
@AllArgsConstructor
public class productRestController {

productServiceImpl productService;
@GetMapping("/")
public List<Product> getAllProducts(){
System.out.println("*********************inside get all ***********************");
return productService.findAll();
}
@GetMapping("/products/{name}")
public Product getProductsByName(@PathVariable("name")Optional<String> name ){
if(name.isPresent())
return productService.findByName(name.get());
else return null;
}
@GetMapping("/products/{price}")
public List<Product> getProductsByPrice(@PathVariable("price")Optional<Integer> price ){
if(price.isPresent())
return productService.findByPrice(price.get());
else return null;
}
@PostMapping("/save")
public ResponseEntity<?> saveProduct(@RequestBody Product product){
Product p = productService.saveOrUpdateProduct(product);
return new ResponseEntity(p, HttpStatus.OK);
}
}

并调用http://localhost:8080/products/,我得到一个错误:

No adapter for handler [com.example.MongoTesr.REST.productRestController@6e98d209]: 
The DispatcherServlet configuration needs to include a HandlerAdapter that supports this handler

我试着用谷歌搜索,但没有发现错误和问题的解决方案。你能告诉我我做错了什么吗?

应用程序属性

spring.data.mongodb.authentication-database=admin
spring.data.mongodb.username=root
spring.data.mongodb.password=rootpassword
spring.data.mongodb.database=test_db
spring.data.mongodb.port=27017
spring.data.mongodb.host=localhost

@RestController("/products")不会做你想做的事!

/products不是一个路径或映射到它或类似的东西,而是:

该值可能指示一个逻辑组件名称的建议,在自动检测到组件的情况下将其转换为Springbean。

来自RestController.valuejavadoc。


如果我们想在类级别上构建路径映射,我们可以使用来实现

...
@RestController  // resp. @Controller
@RequestMapping("/products") //(resp. relative: "products")
public class ...

另请参阅:在类级上使用@RequestMapping

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