springcloud中微服務之間feign傳參

1、自定義類實現RequestInterceptor接口類：

@Component
public class FeignInterceptor implements RequestInterceptor{

    @Override
    public void apply(RequestTemplate template) {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        if (attributes != null) {
            HttpServletRequest request = attributes.getRequest();
            template.header("user",request.getHeader("user"));
        }
    }
}

2、自定義Hystrix的默認隔離策略：網上很多代碼例子

3、如果想要把參數通過HTTP請求的header傳遞到其他服務，就需要另外做些配置，首先你要把參數添加到header里面，然后就可以通過feign傳遞了，如下：

 

 4、MutableHttpServletRequest是一個工具類：

public class MutableHttpServletRequest extends HttpServletRequestWrapper {
    // holds custom header and value mapping
    private final Map<String, String> customHeaders;

    public MutableHttpServletRequest(HttpServletRequest request){
        super(request);
        this.customHeaders = new HashMap<String, String>();
    }

    public void putHeader(String name, String value){
        this.customHeaders.put(name, value);
    }

    public String getHeader(String name) {
        // check the custom headers first
        String headerValue = customHeaders.get(name);

        if (headerValue != null){
            return headerValue;
        }
        // else return from into the original wrapped object
        return ((HttpServletRequest) getRequest()).getHeader(name);
    }

    public Enumeration<String> getHeaderNames() {
        // create a set of the custom header names
        Set<String> set = new HashSet<String>(customHeaders.keySet());

        // now add the headers from the wrapped request object
        @SuppressWarnings("unchecked")
        Enumeration<String> e = ((HttpServletRequest) getRequest()).getHeaderNames();
        while (e.hasMoreElements()) {
            // add the names of the request headers into the list
            String n = e.nextElement();
            set.add(n);
        }

        // create an enumeration from the set and return
        return Collections.enumeration(set);
    }
}

5、另一個服務在想用的地方接收參數：

HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
String userStr = request.getHeader("user");