在Spring MVC中没有参数的@RequestMapping

Question

我在学习Spring MVC时试图理解我的项目代码.

在spring中,@RequestMapping注释需要参数.例如,

@RequestMapping(value="/something", method=RequestMethod.POST)
@RequestMapping(value="/index.html", method=RequestMethod.GET)
@RequestMapping("/index")
@RequestMapping(params="command=GETINFO")

我的项目使用注释,它不使用任何XML进行映射.我有一个以下的控制器结构.

@Controller
public class RuleStepController {
   private static final String ATTRIBUTE_BRANCH = "branch";
    private static final String ATTRIBUTE_EDIT_FORM = "editForm";
 .................
    @Autowired
    private RuleStepService ruleStepService;
    @Autowired
    private PopulationDao populationDao;

     @RequestMapping
    public void ruleStepEntForm(Long populationId, ModelMap model) {
     .....
     editForm.setStepEnt(stepDto);
    }

@RequestMapping
    public void ruleStepOrgCount(RuleStepOrgSearchForm searchForm, ModelMap model){
      .......
model.addAttribute("searchForm", searchForm);
    }

@RequestMapping
    public String ruleStepMgrForm() {
        logger.debug(String.format("ruleStepMgrForm"));
        return "forward:/employee/employeeSearchForm.view?relationshipId=0&roleId=0&formId=stepMgr";
    }

我想了解@RequestMapping何时不带任何参数会有什么意义？

有什么用@AutoWired？

Answer 1

1. 通过注释，@RequestMapping您可以通过多种方式绑定请求参数：

   URI 模板模式，使用注释@PathVariable

   @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";
   }
   

   请求参数和标头值

   @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
       }
   }
   

   使用@RequestParam

   @Controller
   @RequestMapping("/pets")
   @SessionAttributes("pet")
   public class EditPetForm {
   
       @RequestMapping(method = RequestMethod.GET)
       public String setupForm(@RequestParam("petId") int petId, ModelMap model) {
           Pet pet = this.clinic.loadPet(petId);
           model.addAttribute("pet", pet);
           return "petForm";
       }
   }
   

   @RequestBody使用注释映射请求正文

   @RequestMapping(value = "/something", method = RequestMethod.PUT)
   public void handle(@RequestBody String body, Writer writer) throws IOException {
       writer.write(body);
   }
   

2. 自动装配

   @Autowired
   private RuleStepService ruleStepService;
   

   Spring容器之前已经创建了bean ruleStepService。如果你需要在你的类中使用这个bean，你只需要像上面那样声明，容器就会将该bean注入到你的类中。你不需要像这样声明；

   RuleStepService ruleStepService =new RuleStepService(). 
   

   容器将查找bean名称ruleStepService或bean的类型RuleStepService（基于配置中的策略）