问题
I created a resttemplate in my spring boot application like this:
@Configuration
public class MyConfiguration {
@LoadBalanced
@Bean
RestTemplate restTemplate() {
return new RestTemplate();
}
}
This works fine in all classes when autowired. However, in my interceptor, this throws up nullpointer exception.
What could be the reason and how can I configure a loadbalanced (using Ribbon) resttemplate in my interceptor?
Update:
my interceptor:
public class MyInterceptor implements HandlerInterceptorAdapter {
@Autowired
RestTemplate restTemplate;
public boolean preHandle(HttpServletRequest request,
HttpServletResponse response, Object handler)
throws Exception {
HttpHeaders headers = new HttpHeaders();
...
HttpEntity<String> entity = new HttpEntity<String>(headers);
//restTemplate is null here
ResponseEntity<String> result =
restTemplate.exchange("<my micro service url using service name>",
HttpMethod.POST, entity, String.class);
...
return true;
}
Interceptor is added to spring boot application like this:
@Configuration
public class MyConfigAdapter extends WebMvcConfigurerAdapter {
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new MyInterceptor()).addPathPatterns("/*");
}
}
回答1:
You misunderstand how @Autowired works. As soon as you new MyInterceptor() outside of a @Bean method, it will not get autowired.
Do something like below:
@Configuration
public class MyConfigAdapter extends WebMvcConfigurerAdapter {
@Autowired
MyInterceptor myInterceptor;
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(myInterceptor).addPathPatterns("/*");
}
}
来源：https://stackoverflow.com/questions/43243402/spring-cloud-resttemplate-doesnt-get-injected-in-interceptor