FeignClient调用远程服务时整合本地
包装一个用户服务,一部分功能需要调用远程服务,而另一部分功能调用本地方法,如:
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@FeignClient (value= "USER-SERVICE" ) public interface RemoteUserService{ @GetMapping ( "getUserByUserId" ) public User getUserByUserId(String userId); } public interface LocalUserService{ public String getUserId(); } @Service public class LocalUserServiceImpl implements LocalUserService{ @Autowired private HttpServletRequest request; public String getUserId(){ return (String)request.getSession().getAttribute( "user-id" ); } } |
为了简化篇幅,并没有处理异常。
当使用者使用这两个用户相关的服务,就需要自动装载两个Service:
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@Autowired private LocalUserService localUserService; @Autowired private RemoteUserService remoteUserService; |
能不能简化一下呢?将两个服务整合。
尝试将本地方法加入Feign接口
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@FeignClient (value= "USER-SERVICE" ,fallback=UserServiceHystrix. class ) public interface UserService{ @GetMapping ( "getUserByUserId" ) public User getUserByUserId(String userId); public String getUserId(); } @Service public class UserServiceHystrix implements UserService{ @Autowired private HttpServletRequest request; public User getUserByUserId(String userId){ return null ; } public String getUserId(){ return (String)request.getSession().getAttribute( "user-id" ); } } |
Fail:
测试发现,UserService 接口中定义本地方法 getUserId() 编译器直接报错了,要求必须有Mapping注解。
尝试通过实现两个接口
换一个思路,回到最初,在熔断器中实现两个接口:
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@FeignClient (value= "USER-SERVICE" ,fallback=UserServiceHystrix. class ) public interface UserService{ @GetMapping ( "getUserByUserId" ) public User getUserByUserId(String userId); } public interface LocalUserService extends RemoteUserService{ public String getUserId(); } @Service public class UserServiceHystrix implements LocalUserService,RemoteUserService{ @Autowired private HttpServletRequest request; public User getUserByUserId(String userId){ return null ; } public String getUserId(){ return (String)request.getSession().getAttribute( "user-id" ); } } |
Fail:
测试发现,本地方法正常,远程方法根本无效,好像就是一个本地方法,直接走到了熔断方法中。
IS -> HAS
让 RemoteUserService is LocalUserService 既然不行,那么就试试让 LocalUserService has RemoteUserService。
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@FeignClient (value= "USER-SERVICE" ,fallback=UserServiceHystrix. class ) public interface UserService{ @GetMapping ( "getUserByUserId" ) public User getUserByUserId(String userId); } public interface LocalUserService extends RemoteUserService{ public String getUserId(); } @Service public class UserServiceImpl implements LocalUserService,RemoteUserService{ @Autowired private HttpServletRequest request; @Autowire private RemoteUserService remoteUserService; public User getUserByUserId(String userId){ return remoteUserService.getUserByUserId(userId); } public String getUserId(){ return (String)request.getSession().getAttribute( "user-id" ); } } |
SUCCESS:
这样是可以的。编码时稍微麻烦了一点,使用时就清晰多了。
FeignClient服务之间调用
服务A需调用服务B的test方法
B服务不动
A:
最好新建一个server
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@Component @FeignClient (value = "tools" ) public interface ServiceAFeignClient { @RequestMapping (value = "/hi" ) String test(); } |
tools为服务B配置中的spring.application.name, hi为B中Controller的接口
然后A中代码调用新建的server的接口即可,可能会出错
com.netflix.client.ClientException: Load balancer does not have available server for client
A的application配置加
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ribbon: eureka: enabled: true |
以上为个人经验,希望能给大家一个参考,也希望大家多多支持服务器之家。
原文链接:https://blog.csdn.net/54powerman/article/details/79592561