آموزش Spring MVC بخش معرفی Annotation ها

@Controller
class VehicleController {
 
    @RequestMapping(value = "/vehicles/home", method = RequestMethod.GET)
    String home() {
        return "home";
    }
}

@Controller
@RequestMapping(value = "/vehicles", method = RequestMethod.GET)
class VehicleController {
 
    @RequestMapping("/home")
    String home() {
        return "home";
    }
}

@RequestMapping(
  value = "/ex/foos", 
  headers = { "key1=val1", "key2=val2" }, method = GET)
@ResponseBody
public String getFoosWithHeaders() {
    return "Get some Foos with Header";
}

@RequestMapping(
  value = "/ex/foos", 
  method = GET, 
  headers = "Accept=application/json")
@ResponseBody
public String getFoosAsJsonFromBrowser() {
    return "Get some Foos with Header Old";
}

@RequestMapping(
  value = "/ex/foos", 
  method = GET,
  produces = { "application/json", "application/xml" }
)

@PostMapping("/request")
public ResponseEntity postController(
  @RequestBody LoginForm loginForm) {
  
    exampleService.fakeAuthenticate(loginForm);
    return ResponseEntity.ok(HttpStatus.OK);
}

curl -i \
-H "Accept: application/json" \
-H "Content-Type:application/json" \
-X POST --data 
  '{"username": "johnny", "password": "password"}' "https://localhost:8080/.../request"

public class LoginForm {
    private String username;
    private String password;
    // ...
}

public class ResponseTransfer {
    private String text; 
     
    // standard getters/setters
}

@Controller
@RequestMapping("/post")
public class ExamplePostController {
 
    @Autowired
    ExampleService exampleService;
 
    @PostMapping("/response")
    @ResponseBody
    public ResponseTransfer postResponseController(
      @RequestBody LoginForm loginForm) {
        return new ResponseTransfer("Thanks For Posting!!!");
     }
}

{"text":"Thanks For Posting!!!"}

http://localhost:8080/spring-rest/ex/foos/value1/bar/value2

@RequestMapping(value = "/ex/foos/{id}", method = GET)
@ResponseBody
public String getFoosBySimplePathWithPathVariable(
  @PathVariable("id") long id) {
    return "Get a specific Foo with id=" + id;
}

@RequestMapping("/{id}") 
Vehicle getVehicle(@PathVariable long id) { 
  // ... 
}

//http://localhost:8080/spring-rest/ex/foos/1/bar/2

@RequestMapping(value = "/ex/foos/{fooid}/bar/{barid}", method = GET)
@ResponseBody
public String getFoosBySimplePathWithPathVariables
  (@PathVariable long fooid, @PathVariable long barid) {
    return "Get a specific Bar with id=" + barid + 
      " from a Foo with id=" + fooid;
}

@RequestMapping(value = "/ex/bars/{numericId:[\\d]+}", method = GET)
@ResponseBody
public String getBarsBySimplePathWithPathVariable(
  @PathVariable long numericId) {
    return "Get a specific Bar with id=" + numericId;
}

@GetMapping(value = "foos/duplicate")
public String duplicate() {
    return "Duplicate";
}
 
@GetMapping(value = "foos/duplicate")
public String duplicateEx() {
    return "Duplicate";
}

Caused by: java.lang.IllegalStateException: Ambiguous mapping.
  Cannot map 'fooMappingExamplesController' method 
  public java.lang.String org.baeldung.web.controller.FooMappingExamplesController.duplicateEx()
  to {[/ex/foos/duplicate],methods=[GET]}:
  There is already 'fooMappingExamplesController' bean method
  public java.lang.String org.baeldung.web.controller.FooMappingExamplesController.duplicate() mapped.

@GetMapping(value = "foos/duplicate/xml", produces = MediaType.APPLICATION_XML_VALUE)
public String duplicateXml() {
    return "Duplicate";
}
 
@GetMapping(value = "foos/duplicate/json", produces = MediaType.APPLICATION_JSON_VALUE)
public String duplicateJson() {
    return "Duplicate";
}

@Configuration
@EnableWebMvc
@ComponentScan({ "org.baeldung.spring.web.controller" })
public class MvcConfig {
    //
}

@EnableWebMvc
@Configuration
public class WebConfig implements WebMvcConfigurer {
 
   @Override
   public void addViewControllers(ViewControllerRegistry registry) {
      registry.addViewController("/").setViewName("index");
   }
 
   @Bean
   public ViewResolver viewResolver() {
      InternalResourceViewResolver bean = new InternalResourceViewResolver();
 
      bean.setViewClass(JstlView.class);
      bean.setPrefix("/WEB-INF/view/");
      bean.setSuffix(".jsp");
 
      return bean;
   }
}

public class MainWebAppInitializer implements WebApplicationInitializer {
    @Override
    public void onStartup(final ServletContext sc) throws ServletException {
 
        AnnotationConfigWebApplicationContext root = 
          new AnnotationConfigWebApplicationContext();
         
        root.scan("com.baeldung");
        sc.addListener(new ContextLoaderListener(root));
 
        ServletRegistration.Dynamic appServlet = 
          sc.addServlet("mvc", new DispatcherServlet(new GenericWebApplicationContext()));
        appServlet.setLoadOnStartup(1);
        appServlet.addMapping("/");
    }
}

<context:component-scan base-package="com.baeldung.web.controller" />
<mvc:annotation-driven />    
 
<bean id="viewResolver"
      class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/view/" />
        <property name="suffix" value=".jsp" />
    </bean>
 
    <mvc:view-controller path="/" view-name="index" />
 
</beans>

http://localhost:8080/spring-rest/ex/bars?id=100

//http://localhost:8080/spring-rest/ex/bars?id=100

@RequestMapping(value = "/ex/bars", method = GET)
@ResponseBody
public String getBarBySimplePathWithRequestParam(
  @RequestParam("id") long id) {
    return "Get a specific Bar with id=" + id;
}

//http://localhost:8080/spring-rest/ex/bars?id=100&second=something

@RequestMapping(
  value = "/ex/bars", 
  params = { "id", "second" }, 
  method = GET)
@ResponseBody
public String getBarBySimplePathWithExplicitRequestParams(
  @RequestParam("id") long id) {
    return "Narrow Get a specific Bar with id=" + id;
}

@RequestMapping("/buy")
Car buyCar(@RequestParam(defaultValue = "5") int seatCount) {
    // ...
}

//http://localhost:8080/spring-rest/ex/advanced/foos
//http://localhost:8080/spring-rest/ex/advanced/bars

@RequestMapping(
  value = { "/ex/advanced/bars", "/ex/advanced/foos" }, 
  method = { RequestMethod.PUT, RequestMethod.POST })
@ResponseBody
public String getFoosOrBarsByPath() {
    return "Advanced - Get some Foos or Bars";
}

@ExceptionHandler(IllegalArgumentException.class)
void onIllegalArgumentException(IllegalArgumentException exception) {
    // ...
}

@ExceptionHandler(IllegalArgumentException.class)
@ResponseStatus(HttpStatus.BAD_REQUEST)
void onIllegalArgumentException(IllegalArgumentException exception) {
    // ...
}

@CrossOrigin
@RequestMapping("/hello")
String hello() {
    return "Hello World!";
}

@RequestMapping(value = "/addEmployee", method = RequestMethod.POST)
public String submit(@ModelAttribute("employee") Employee employee) {
    // Code that uses the employee object
 
    return "employeeView";
}

@ModelAttribute
public void addAttributes(Model model) {
    model.addAttribute("msg", "Welcome to the Netherlands!");
}

@ModelAttribute("vehicle")
Vehicle getVehicle() {
    // ...
}

@Controller
public class ModelController {
 
    @ModelAttribute(name= "countrieslist")
    public List<String> populateCountries() {
 
        List<String> countries= new ArrayList<String>();
        countries.add("India");
        countries.add("United States");
        countries.add("Japan");
        countries.add("Australia");
        countries.add("Canda");     
 
        return countries;
    }
 
    @RequestMapping(value= "/init", method= RequestMethod.GET)
    public ModelAndView initView(@ModelAttribute(name= "countrieslist") List<String> countries) {
 
        ModelAndView modelview = new ModelAndView();
        modelview.addObject("message", "This is an example of using the @ModelAttribute annotation .....!");
        modelview.setViewName("output");
 
        return modelview;
    }
}

<form:form method="POST" action="/spring-mvc-basics/addEmployee"
  modelAttribute="employee">
    <form:label path="name">Name</form:label>
    <form:input path="name" />
     
    <form:label path="id">Id</form:label>
    <form:input path="id" />
     
    <input type="submit" value="Submit" />
</form:form>

@XmlRootElement
public class Employee {
 
    private long id;
    private String name;
 
    public Employee(long id, String name) {
        this.id = id;
        this.name = name;
    }
 
    // standard getters and setters removed
}

@Controller
@ControllerAdvice
public class EmployeeController {
 
    private Map<Long, Employee> employeeMap = new HashMap<>();
 
    @RequestMapping(value = "/addEmployee", method = RequestMethod.POST)
    public String submit(
      @ModelAttribute("employee") Employee employee,
      BindingResult result, ModelMap model) {
        if (result.hasErrors()) {
            return "error";
        }
        model.addAttribute("name", employee.getName());
        model.addAttribute("id", employee.getId());
 
        employeeMap.put(employee.getId(), employee);
 
        return "employeeView";
    }
 
    @ModelAttribute
    public void addAttributes(Model model) {
        model.addAttribute("msg", "Welcome to the Netherlands!");
    }
}

<h3>${msg}</h3>
Name : ${name}
ID : ${id}

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.6.RELEASE</version>
</parent>