@RequestMapping 详解

RequestMapping是一个用来处理请求地址映射的注解，可用于类或方法上。用于类上，表示类中的所有响应请求的方法都是以该地址作为父路径。
RequestMapping注解有六个属性，下面我们把她分成三类进行说明。

三类

1、 value,method

value：指定请求的实际地址，指定的地址可以是URI Template 模式（后面将会说明）；
method：指定请求的method类型， GET、POST、PUT、DELETE等；

2、 consumes,produces

consumes： 指定处理请求的提交内容类型（Content-Type），例如application/json, text/html;
produces: 指定返回的内容类型，仅当request请求头中的(Accept)类型中包含该指定类型才返回；

3、 params，headers；

params： 指定request中必须包含某些参数值是，才让该方法处理。
headers： 指定request中必须包含某些指定的header值，才能让该方法处理请求。

示例：

1、value / method 示例:

  默认RequestMapping("....str...")即为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值为以下三类：

A） 可以指定为普通的具体值；
B) 可以指定为含有某变量的一类值(URI Template Patterns with Path Variables)；
C) 可以指定为含正则表达式的一类值( 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的样例：方法仅处理request Content-Type为“application/json”类型的请求。
@Controller  
@RequestMapping(value = "/pets", method = RequestMethod.POST, consumes="application/json")  
public void addPet(@RequestBody Pet pet, Model model) {      
    // implementation omitted  
}  


//[2].produces的样例：方法仅处理request请求中Accept头中包含了"application/json"的请求，同时暗示了返回的内容类型为application/json;
@Controller  
@RequestMapping(value = "/pets/{petId}", method = RequestMethod.GET, produces="application/json")  
@ResponseBody  
public Pet getPet(@PathVariable String petId, Model model) {      
    // implementation omitted  
}  

3、 params、headers 示例

//params的样例：仅处理请求中包含了名为“myParam”，值为“myValue”的请求；
@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的样例：仅处理request的header中包含了指定“Refer”请求头和对应值为"http://www.ifeng.com/"的请求；
@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  
  }  
}