@RequestMapping 詳解

RequestMapping是一個用來處理請求地址映射的註解，可用於類或方法上。用於類上，表示類中的全部響應請求的方法都是以該地址做爲父路徑。
RequestMapping註解有六個屬性，下面咱們把她分紅三類進行說明。

三類

一、 value,method

value：指定請求的實際地址，指定的地址能夠是URI Template 模式（後面將會說明）；
method：指定請求的method類型， GET、POST、PUT、DELETE等；

二、 consumes,produces

consumes： 指定處理請求的提交內容類型（Content-Type），例如application/json, text/html;
produces: 指定返回的內容類型，僅當request請求頭中的(Accept)類型中包含該指定類型才返回；

三、 params，headers；

params： 指定request中必須包含某些參數值是，才讓該方法處理。
headers： 指定request中必須包含某些指定的header值，才能讓該方法處理請求。

示例：

一、value / method 示例:

  默認RequestMapping("....str...")即爲value的值；

@Controller  
@RequestMapping("/appointments")  
public class AppointmentsController {  
    private final AppointmentBook appointmentBook;  
    @Autowired  
    public AppointmentsController(AppointmentBook appointmentBook) {  
        this.appointmentBook = appointmentBook;  
    }  
    @RequestMapping(method = RequestMethod.GET)  
    public Map<String, Appointment> get() {  
        return appointmentBook.getAppointmentsForToday();  
    }  
    @RequestMapping(value="/{day}", method = RequestMethod.GET)  
    public Map<String, Appointment> getForDay(@PathVariable @DateTimeFormat(iso=ISO.DATE) Date day, Model model) {  
        return appointmentBook.getAppointmentsForDay(day);  
    }  
    @RequestMapping(value="/new", method = RequestMethod.GET)  
    public AppointmentForm getNewForm() {  
        return new AppointmentForm();  
    }  
  
    @RequestMapping(method = RequestMethod.POST)  
    public String add(@Valid AppointmentForm appointment, BindingResult result) {  
        if (result.hasErrors()) {  
            return "appointments/new";  
        }  
        appointmentBook.addAppointment(appointment);  
        return "redirect:/appointments";  
    }  
}  

注意: value的uri值爲如下三類：

A） 能夠指定爲普通的具體值；
B) 能夠指定爲含有某變量的一類值(URI Template Patterns with Path Variables)；
C) 能夠指定爲含正則表達式的一類值( URI Template Patterns with Regular Expressions);

//[1].example B)
@RequestMapping(value="/owners/{ownerId}", method=RequestMethod.GET)  
public String findOwner(@PathVariable String ownerId, Model model) {  
  Owner owner = ownerService.findOwner(ownerId);    
  model.addAttribute("owner", owner);    
  return "displayOwner";   
}  

//[2].example C)
@RequestMapping("/spring-web/{symbolicName:[a-z-]+}-{version:\d\.\d\.\d}.{extension:\.[a-z]}")  
  public void handle(@PathVariable String version, @PathVariable String extension) { 
    // ...  
  }  
}  

2 、consumes、produces 示例

//[1].cousumes的樣例：方法僅處理request Content-Type爲「application/json」類型的請求。
@Controller  
@RequestMapping(value = "/pets", method = RequestMethod.POST, consumes="application/json")  
public void addPet(@RequestBody Pet pet, Model model) {      
    // implementation omitted  
}  


//[2].produces的樣例：方法僅處理request請求中Accept頭中包含了"application/json"的請求，同時暗示了返回的內容類型爲application/json;
@Controller  
@RequestMapping(value = "/pets/{petId}", method = RequestMethod.GET, produces="application/json")  
@ResponseBody  
public Pet getPet(@PathVariable String petId, Model model) {      
    // implementation omitted  
}  

三、 params、headers 示例

//params的樣例：僅處理請求中包含了名爲「myParam」，值爲「myValue」的請求；
@Controller  
@RequestMapping("/owners/{ownerId}")  
public class RelativePathUriTemplateController {  
  
  @RequestMapping(value = "/pets/{petId}", method = RequestMethod.GET, params="myParam=myValue")  
  public void findPet(@PathVariable String ownerId, @PathVariable String petId, Model model) {      
    // implementation omitted  
  }  
}  
 
//headers的樣例：僅處理request的header中包含了指定「Refer」請求頭和對應值爲"http://www.ifeng.com/"的請求；
@Controller  
@RequestMapping("/owners/{ownerId}")  
public class RelativePathUriTemplateController {  
  
@RequestMapping(value = "/pets", method = RequestMethod.GET, headers="Referer=http://www.ifeng.com/")  
  public void findPet(@PathVariable String ownerId, @PathVariable String petId, Model model) {      
    // implementation omitted  
  }  
}