將一個@RequestMapping定義的方法對映為兩個http服務----記一次有趣的排查問題過程
阿新 • • 發佈：2021-01-16
小夥伴遇到個問題，某個controller釋出的http服務直接訪問沒問題，通過nginx轉發後就報404，此模組其他url訪問都正常。。
controller程式碼如下：
@RequestMapping("/addrExport.spr")
public class AddrExportController
@RequestMapping(params = "method=exportDynamicQueryData")
public void exportDynamicQueryData(HttpServletRequest request, HttpServletResponse response, String downLoadData) {
System.out.println("hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh");
.....
} server {
listen 8888;
......
location /portal/space-addr/ {
proxy_pass http://localhost:8299/space-addr/;
}
.....
}使用nginx埠訪問的url如下，就是此url訪問404 http://localhost:8888/portal/space-addr/addrExport.spr?method=exportDynamicQueryData 一陣兵荒馬亂，小夥伴發現此url轉發到後臺的路徑為 http://localhost:8299/space-addr/addrExport.spr?method=exportDynamicQueryData 多了一個space-addr 此時有兩種方案， 方案1.在controller裡@RequestMapping時增加space-addr字首 方案2.修改nginx對映去掉proxy_pass中多餘的字首，注意紅色字型部分去掉了space-addr，見下文：
location /portal/space-addr/ {
proxy_pass http://localhost:8299/;
}
感謝spring的日誌輸出，偶然搜尋發現瞭如下內容，什麼鬼，竟然增加了兩個rescommon/service/callServerFunction相關的requestmapping：一個有space-addr字首，一個無字首。。 最終發現公共側對ResCommonServiceController做了特殊處理，具體見CommonConfig類的registerCommonServerMapping方法(見下圖)，預設會生成兩個requestmapping： 1./rescommon/service/callServerFunction 2.${pub.commonservice.prefix}/rescommon/service/callServerFunction,對於排查問題的這個模組存在配置pub.commonservice.prefix=space-addr，最終效果為space-addr/rescommon/service/callServerFunction 正是因為生成了兩個requestmapping，所以才會出現nginx裡轉發規則配或不配space-addr都沒問題的情況，因為都能匹配到requestmapping。。
類全文如下：
1 @Configuration
2 public class CommonConfig {
3
4 @Value("${pub.commonservice.prefix}")
5 String prefix;
6
7 @Bean
8 public ResCommonServiceController registerCommonServiceController() {
9 return new ResCommonServiceController();
10 }
11
12 @Autowired
13 public void registerCommonServerMapping(ResCommonServiceController registerCommonServiceController, RequestMappingHandlerMapping mapping) {
14 String uri = "/rescommon/service/";
15 RequestMappingInfo requestMappingInfo = RequestMappingInfo.paths(uri).build();
16 ResRequestMappingHandlerMapping resRequestMappingHandlerMapping = new ResRequestMappingHandlerMapping(mapping, requestMappingInfo);
17 resRequestMappingHandlerMapping.detectHandlerMethods(registerCommonServiceController);
18 if (!("".equals(prefix) || prefix == null || "${pub.commonservice.prefix}".equals(prefix))) {
19 String[] split = prefix.split(",");
20 for (String prefix1 : split) {
21 ResRequestMappingHandlerMapping resRequestMappingHandlerMapping1 = new ResRequestMappingHandlerMapping(mapping, RequestMappingInfo.paths(prefix1 + uri).build());
22 resRequestMappingHandlerMapping1.detectHandlerMethods(registerCommonServiceController);
23 }
24 }
25 }
26 }
這個寫法很有趣，第一次見。。自定義的ResRequestMappingHandlerMapping類擴充套件了spring的RequestMappingHandlerMapping，覆寫了detectHandlerMethods方法，在registerMapping時將自定義的url字首和method上的url做拼接。
1 public class ResRequestMappingHandlerMapping extends RequestMappingHandlerMapping {
2
3 /**
4 * 代理物件
5 */
6 private RequestMappingHandlerMapping requestMappingHandlerMapping;
7
8 /**
9 * 存放類的RequestMapping資訊
10 */
11 RequestMappingInfo typeMapping;
12
13 public ResRequestMappingHandlerMapping(RequestMappingHandlerMapping requestMappingHandlerMapping, RequestMappingInfo typeMapping) {
14 this.requestMappingHandlerMapping = requestMappingHandlerMapping;
15 this.typeMapping = typeMapping;
16 }
17
18 @Override
19 public void detectHandlerMethods(final Object handler) {
20 if(handler == null){
21 return;
22 }
23 Class<?> handlerType = (handler instanceof String ? getApplicationContext().getType((String) handler) : handler.getClass());
24 final Class<?> userType = ClassUtils.getUserClass(handlerType);
25
26 Map<Method, RequestMappingInfo> methods = MethodIntrospector.selectMethods(userType, new MethodIntrospector.MetadataLookup<RequestMappingInfo>() {
27 public RequestMappingInfo inspect(Method method) {
28 try {
29 return getMappingForMethod(method, userType);
30 }
31 catch (Exception ex) {
32 throw new IllegalStateException("Invalid mapping on handler class [" + userType.getName() + "]: " + method, ex);
33 }
34 }
35 });
36
37 if (logger.isDebugEnabled()) {
38 logger.debug(methods.size() + " request handler methods found on " + userType + ": " + methods);
39 }
40 for (Map.Entry<Method, RequestMappingInfo> entry : methods.entrySet()) {
41 Method invocableMethod = AopUtils.selectInvocableMethod(entry.getKey(), userType);
42 RequestMappingInfo mapping = entry.getValue();
43 if (typeMapping != null) {
44 mapping = typeMapping.combine(mapping);
45 }
46 requestMappingHandlerMapping.registerMapping(mapping, handler, invocableMethod);
47 }
48 }
至此，謎題解開了，因為公共側對ResCommonServiceController類做了特殊定製，使其釋出的@RequestMapping方法釋出了兩個http服務。。所以nginx的轉發規則帶不帶字首都不影響功能使用。。