Question

我在学习Spring MVC时试图理解我的项目代码。

在春天@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，并且它不使用任何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什么时候没有任何参数会有什么意义？

@AutoWired的用途是什么？

Answer 1

使用注释@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";
    }
}

使用@RequestBody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);
}

自动装配
```
@Autowired
private RuleStepService ruleStepService;
```
Spring Container之前创建了bean ruleStepService。如果你需要在你的类中使用这个bean，你只需要如上所述声明，容器会将bean注入你的类。你不需要声明像;
```
RuleStepService ruleStepService =new RuleStepService(). 
```
Container将找到bean名称ruleStepService或bean具有类型RuleStepService（基于配置中的策略）

Answer 2

控制器中使用的@RequestMapping注释不仅允许我们实现URL模式匹配，而且还允许从请求URL本身提取变量。因此，您必须拥有@RequestMapping，您是否有参数。默认情况下，HTTP方法由@RequestMapping映射的是GET

以下是来自泉源的两个很好的参考资料：

http://static.springsource.org/spring/docs/3.0.x/javadoc-api/org/springframework/web/bind/annotation/RequestMapping.html

http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/mvc.html

自动装配

这是有用的链接

http://howtodoinjava.com/2013/05/08/spring-beans-autowiring-concepts/

在Spring MVC中没有参数的@RequestMapping

2 个答案: