在闲暇时间开始阅读Spring的官方文档,感觉收获很大,记录了一点笔记。
When no HTTP methods are explicitly declared the "Allow" header is set to "GET,HEAD,POST,PUT,PATCH,DELETE,OPTIONS". Ideally always declare the HTTP method(s) an @RequestMapping method is intended to handle.
@RequestMapping(method = RequestMethod.POST)
public String processSubmit(@ModelAttribute("pet") Pet pet, Model model, BindingResult result) { ... }
正确的代码片段是:
@RequestMapping(method = RequestMethod.POST)
public String processSubmit(@ModelAttribute("pet") Pet pet, BindingResult result, Model model) { ... }
@RequestMapping注解方法支持的参数类型
@RequestMapping注解方法支持的返回值类型
@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";
}
// ...
}
@Configuration
@EnableWebMvc
public class WebConfig { }
使用XML文件中的mvc:annoation-driven元素也可以,具体代码如下:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation=" http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<mvc:annotation-driven/>
</beans>
所谓开启MVC支持,实际上是注册了RequestMappingHandlerMapping和RequestMappingHandlerAdapter,以及ExceptionHandlerExceptionResolver这些bean,使得在控制器中可以使用@RequestMapping、@ExceptionHandler这些注解。开启MVC支持,也提供了如下功能:
@Configuration
@EnableWebMvc
public class WebConfig extends WebMvcConfigurerAdapter {
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
registry.addResourceHandler("/resources/**").addResourceLocations("/public-resources/");
}
}
如果使用XML配置,则对应的配置代码如下:
<mvc:resources mapping="/resources/**" location="/public-resources/"/>
mapping属性必须是Ant模式,由SimpleUrlHandlerMapping解析url解析;location属性必须指定一个或者多个有效的资源目录位置,多个资源位置可以用逗号分割。对于每个服务端接受的请求,Spring会按照location属性指定的顺序进行匹配。例如,如果某个服务提供的资源既来自web应用根目录,又来自classpath中的/META-INF/public-web-resources目录,则对应的Java Config代码如下:
@EnableWebMvc
@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
registry.addResourceHandler("/resources/**")
.addResourceLocations("/", "classpath:/META-INF/public-web-resources/");
}
}
同样的功能,XML配置代码如下:
<mvc:resources mapping="/resources/**" location="/, classpath:/META-INF/public-web-resources/"/>