如何在Spring Boot REST中默认执行最新版本的endpoint？

Question

@GetMapping(value = "/student/header", headers = {"X-API-VERSION=1"})
public StudentV1 headerV1() {
    return serviceImpl.headerV1();
}

@GetMapping(value = "/student/header", headers = {"X-API-VERSION=2"})
public StudentV1 headerV2() {
    return serviceImpl.headerV2();
}

Answer 1

如果我答对了您的问题，您希望不带x-api-version头发送的请求将自动路由到headerv2()方法

可以这样做：

从概念上讲，您需要一个在Spring MVC Dispatch Servlet之前执行的Web过滤器，并且您必须检查请求是否包含一个头，如果它没有添加一个您认为应该是最新版本的头（从配置或其他方面）。

// The web filter 
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.IOException;

@Component
@Order(1)
public class LatestVersionFilter implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) servletRequest;
        if(req.getHeader("X-API-VERSION")== null) {
            HeaderMapRequestWrapper wrappedRequest = new HeaderMapRequestWrapper(req);
            wrappedRequest.addHeader("X-API-VERSION", resolveLastVersion());
            filterChain.doFilter(wrappedRequest, servletResponse);
        } else {
            filterChain.doFilter(servletRequest, servletResponse);
        }
    }

    private String resolveLastVersion() {
        // read from configuration or something
        return "2";
    }
}

class HeaderMapRequestWrapper extends HttpServletRequestWrapper {
        /**
         * construct a wrapper for this request
         *
         * @param request
         */
        public HeaderMapRequestWrapper(HttpServletRequest request) {
            super(request);
        }

        private Map<String, String> headerMap = new HashMap<String, String>();

        /**
         * add a header with given name and value
         *
         * @param name
         * @param value
         */
        public void addHeader(String name, String value) {
            headerMap.put(name, value);
        }

        @Override
        public String getHeader(String name) {
            String headerValue = super.getHeader(name);
            if (headerMap.containsKey(name)) {
                headerValue = headerMap.get(name);
            }
            return headerValue;
        }

        /**
         * get the Header names
         */
        @Override
        public Enumeration<String> getHeaderNames() {
            List<String> names = Collections.list(super.getHeaderNames());
            for (String name : headerMap.keySet()) {
                names.add(name);
            }
            return Collections.enumeration(names);
        }

        @Override
        public Enumeration<String> getHeaders(String name) {
            List<String> values = Collections.list(super.getHeaders(name));
            if (headerMap.containsKey(name)) {
                values.add(headerMap.get(name));
            }
            return Collections.enumeration(values);
        }

    }

null