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<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";
}
}
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")
@ResponseBody
public 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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