我有两个控制器:
@Controller
@Order(Ordered.LOWEST_PRECEDENCE)
public class BaseController {
@RequestMapping("/hello.html")
public String hello(ModelMap model) {
model.addAttribute("hello", "world");
return "hello";
}
}
@Controller
public class ProjectSpecificController {
@Autowired
private BaseController baseController;
@Override
@RequestMapping("/hello.html")
public String hello(ModelMap model) {
model.addAttribute("project", "name");
return baseController.hello(model);
}
}
因为春天会触发这个异常:java.lang.IllegalStateException: Ambiguous mapping found. Cannot map 'baseController' bean method public java.lang.String com.example.BaseController.hello(org.springframework.ui.ModelMap) to {[/hello.html],methods=[],params=[],headers=[],consumes=[],produces=[],custom=[]}: There is already 'projectSpecificController' bean method public java.lang.String com.example.ProjectSpecificController.hello(org.springframework.ui.ModelMap) mapped.
我想先使用 @Order
注释来映射ProjectSpecificController.hello
,如果已经找到了映射/hello.html
则忽略其他映射并且不注册它们的方法:
public class OrderedRequestMappingHandlerMapping extends RequestMappingHandlerMapping {
@Override
protected void registerHandlerMethod(Object handler, Method method, RequestMappingInfo mapping) {
try {
super.registerHandlerMethod(handler, method, mapping);
} catch (IllegalStateException e) {
// mapping already happened for a controller of higher precedence, so ignore
}
}
}
捕获异常就足够了,还是我必须自己查找@Order
注释?如果我必须自己处理@Order
注释:实现我的计划的最佳实践是什么?
如果我是你,我不会尝试那样做。
如果我正确理解,您有一个BaseController
并且想要覆盖 URL 的处理。我已经做了一些离那不远的事情:
- 将处理委托给基本控制器中的常规方法(未
@RequestMapping
注释) - 在扩展控制器的类中重写该方法
- 将子类用作 Bean(而不是父类)
困难的部分是您必须显式声明正确的控制器 bean。我用XML做了,所以很容易(只是一行更改xml文件)。在 Java 配置中,我会在@Configuration
注释类中显式声明控制器 bean。
在全球范围内,它看起来像:
public class BaseController {
@RequestMapping("/hello.html")
public String hello(ModelMap model) {
return doHello(model);
}
protected String doHello(ModelMap model) {
model.addAttribute("hello", "world");
return "hello";
}
}
public class ProjectSpecificController extends BaseController{
@Override
protected String doHello(ModelMap model) {
model.addAttribute("project", "name");
return super.doHello(model);
}
}
@Configuration
class HelloConfig {
// other configuration elements ...
@Bean
public BaseController helloController() {
// implement the logic to choose the right implementation
return (specific ? new ProjectSpecificController() : new BaseController());
}
// other configuration elements ...
}