背景
公司最近有一个项目二期需要对一些功能进行改造，涉及部分框架内置业务接口个性化定制，兼容老接口功能并且增加一部分新的数据返回，由于前端调用这些接口分布较多且较为零碎，修改测试成本较大，所以打算在框架层面提供路由覆盖功能，加快项目进度减少无技术含量的修改带来的系统风险
设计
提供自定义注解指定需要覆盖的路由及新路由地址
系统启动时扫描所有注解数据并进行映射处理
注册自定义路由映射配置类
实现
注解定义
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface CoverRoute {
String value() default "";
}注解扫描及管理
在系统启动时调用initRoute方法，把原路由和对应的覆盖路由映射到map键值对中
public class ConverRouteUtil {
private static HashMap<String, String> mappingRegist = new HashMap<>();
public static void initRoute(Class runtimeClass, List<String> extraPackageNameList) {
List<Class<?>> scanClassList = new ArrayList<>();
if (!runtimeClass.getPackage().getName().equals(Application.class.getPackage().getName())) {
scanClassList.addAll(ScanUtil.getAllClassByPackageName_Annotation(runtimeClass.getPackage(), CoverRoute.class));
}
for (String packageName : extraPackageNameList) {
scanClassList.addAll(ScanUtil.getAllClassByPackageName_Annotation(packageName, CoverRoute.class));
}
for (Class clazz : scanClassList) {
CoverRoute coverRoute = (CoverRoute) clazz.getAnnotation(CoverRoute.class);
if (StringUtil.isEmpty(coverRoute.value())) {
continue;
}
RequestMapping requestMapping = (RequestMapping) clazz.getAnnotation(RequestMapping.class);
String classRoute = "";
if (requestMapping != null) {
classRoute = requestMapping.value()[0];
} else {
continue;
}
List<Method> methodList = Arrays.asList(clazz.getDeclaredMethods());
for (Method method : methodList) {
PostMapping postMapping = method.getAnnotation(PostMapping.class);
String methodRoute = "";
if (postMapping != null) {
methodRoute = postMapping.value()[0];
} else {
GetMapping getMapping = method.getAnnotation(GetMapping.class);
if (getMapping != null) {
methodRoute = getMapping.value()[0];
}
}
if (!StringUtil.isEmpty(classRoute) && !StringUtil.isEmpty(methodRoute)) {
String orginalRoute = coverRoute.value() + methodRoute;
String redirectRoute = classRoute + methodRoute;
mappingRegist.put(orginalRoute, redirectRoute);
}
}
}
if (mappingRegist.size() > 0) {
System.out.println("扫描路由方法覆盖：" + mappingRegist.size() + "个");
}
}
public static boolean checkExistCover(String orginalRoute) {
return mappingRegist.containsKey(orginalRoute);
}
public static String getRedirectRoute(String orginalRoute) {
return mappingRegist.get(orginalRoute);
}
}自定义RequestMappingHandlerMapping
继承RequestMappingHandlerMapping重写lookupHandlerMethod方法，在spring进行路由寻址时进行覆盖
public class CustomRequestMappingHandlerMapping extends RequestMappingHandlerMapping {
@Override
protected HandlerMethod lookupHandlerMethod(String lookupPath, HttpServletRequest request) throws Exception {
if(ConverRouteUtil.checkExistCover(lookupPath)){
String redirectRoute = ConverRouteUtil.getRedirectRoute(lookupPath);
request.setAttribute("redirectTag","1");
request.setAttribute("redirectRoute",redirectRoute);
request.setAttribute("lookupPath",lookupPath);
lookupPath = redirectRoute;
}else{
request.setAttribute("redirectTag","0");
}
return super.lookupHandlerMethod(lookupPath, request);
}
@Override
protected RequestMappingInfo getMatchingMapping(RequestMappingInfo info, HttpServletRequest request) {
String redirectTag = ConvertOp.convert2String(request.getAttribute("redirectTag"));
if(redirectTag.equals("1")){
String redirectRoute = ConvertOp.convert2String(request.getAttribute("redirectRoute"));
boolean check = false;
if( info.getPatternsCondition()!=null){
Set<String> set = info.getPatternsCondition().getPatterns();
if(set.size()>0){
String[] array = new String[set.size()];
array = set.toArray(array);
String pattern = array[0];
if(pattern.equals(redirectRoute)){
check = true;
}
}
}
if(check){
return info;
}else{
return super.getMatchingMapping(info, request);
}
}else{
return super.getMatchingMapping(info, request);
}
}
}注册RequestMappingHandlerMapping
@Component
public class WebRequestMappingConfig implements WebMvcRegistrations {
public RequestMappingHandlerMapping getRequestMappingHandlerMapping() {
RequestMappingHandlerMapping handlerMapping = new CustomRequestMappingHandlerMapping();
handlerMapping.setOrder(0);
return handlerMapping;
}
}使用示例
在个性化接口类增加@CoverRoute注解，指定需要覆盖的路由地址，创建相同路由路径的的方法即可，访问原来的接口地址会自动转发到项目个性化接口地址
原接口
@Controller
@RequestMapping("/example/original")
public class RedirectOriginalExampleController {
@PostMapping("/getConfig")
@ResponseBody
@AnonymousAccess
public Object getConfig(@RequestBody Map<String, Object> params) {
Result result = Result.okResult();
result.add("tag","original");
return result;
}
}新接口
@Controller
@RequestMapping("/example/redirect")
@CoverRoute("/example/original")
public class RedirectExampleController {
@PostMapping("/getConfig")
@ResponseBody
public Object getConfig(@RequestBody Map<String, Object> params) {
Result result = Result.okResult();
String param1 = ConvertOp.convert2String(params.get("param1"));
result.add("tag","redirect");
result.add("param1",param1);
return result;
}
} 
