简介：

@RequestMapping

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（分成三类进行说明）与六个基本用法，

一、属性

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。

1、value  / method 示例

默认RequestMapping("....str...")即为value的值；

@Controller@RequestMapping("/appointments")public class AppointmentsController {    private AppointmentBook appointmentBook;        @Autowired    public AppointmentsController(AppointmentBook appointmentBook) {        this.appointmentBook = appointmentBook;    }    @RequestMapping(method = RequestMethod.GET)    public Map
     
       get() {        return appointmentBook.getAppointmentsForToday();    }    @RequestMapping(value="/{day}", method = RequestMethod.GET)    public Map
      
        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";    }}
      
     

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); 

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"; }

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

cousumes的样例：

@Controller@RequestMapping(value = "/pets", method = RequestMethod.POST, consumes="application/json")public void addPet(@RequestBody Pet pet, Model model) {        // implementation omitted}

方法仅处理request Content-Type为“application/json”类型的请求。

produces的样例：

@Controller@RequestMapping(value = "/pets/{petId}", method = RequestMethod.GET, produces="application/json")@ResponseBodypublic Pet getPet(@PathVariable String petId, Model model) {        // implementation omitted}

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;

3 params、headers 示例

params的样例：

@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  }}

仅处理请求中包含了名为“myParam”，值为“myValue”的请求；

headers的样例：

@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  }}

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；

二、用法

1）最基本的，方法级别上应用，例如： 

@RequestMapping(value="/departments")  public String simplePattern(){      System.out.println("simplePattern method was called");    return "someResult";    }

则访问http://localhost/xxxx/departments的时候，会调用 simplePattern方法了 

2） 参数绑定 

@RequestMapping(value="/departments")  public String findDepatment(    @RequestParam("departmentId") String departmentId){          System.out.println("Find department with ID: " + departmentId);      return "someResult";    }

  形如这样的访问形式： 

   /departments?departmentId=23就可以触发访问findDepatment方法了 

3 REST风格的参数 

@RequestMapping(value="/departments/{departmentId}")  public String findDepatment(@PathVariable String departmentId){      System.out.println("Find department with ID: " + departmentId);    return "someResult";    }

  形如REST风格的地址访问，比如： 

/departments/23，其中用(@PathVariable接收rest风格的参数 

4 REST风格的参数绑定形式之2 

   先看例子，这个有点象之前的：

@RequestMapping(value="/departments/{departmentId}")  public String findDepatmentAlternative(    @PathVariable("departmentId") String someDepartmentId){        System.out.println("Find department with ID: " + someDepartmentId);      return "someResult";    }

 

   这个有点不同，就是接收形如/departments/23的URL访问，把23作为传入的departmetnId,，但是在实际的方法findDepatmentAlternative中，使用 

@PathVariable("departmentId") String someDepartmentId，将其绑定为 

someDepartmentId,所以这里someDepartmentId为23 

5 url中同时绑定多个id 

 

@RequestMapping(value="/departments/{departmentId}/employees/{employeeId}")  public String findEmployee(    @PathVariable String departmentId,    @PathVariable String employeeId){        System.out.println("Find employee with ID: " + employeeId +         " from department: " + departmentId);      return "someResult";    }

6 支持正则表达式 

@RequestMapping(value="/{textualPart:[a-z-]+}.{numericPart:[\\d]+}")  public String regularExpression(    @PathVariable String textualPart,    @PathVariable String numericPart){        System.out.println("Textual part: " + textualPart +         ", numeric part: " + numericPart);      return "someResult";  }

 

  

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