作者： JadePeng

出處：https://www.cnblogs.com/xiaoqi/p/spring-boot-route.html

在我們的rest服務(wù)中，需要暴露一個中間件的接口給用戶，但是需要經(jīng)過rest服務(wù)的認(rèn)證，這是典型的網(wǎng)關(guān)使用場景。可以引入網(wǎng)關(guān)組件來搞定，但是引入zuul等中間件會增加系統(tǒng)復(fù)雜性，這里實現(xiàn)一個超輕量級的網(wǎng)關(guān)，只實現(xiàn)請求轉(zhuǎn)發(fā)，認(rèn)證等由rest服務(wù)的spring security來搞定。

如何進(jìn)行請求轉(zhuǎn)發(fā)呢？ 熟悉網(wǎng)絡(luò)請求的同學(xué)應(yīng)該很清楚，請求無非就是請求方式、HTTP header，以及請求body，我們將這些信息取出來，透傳給轉(zhuǎn)發(fā)的url即可。

舉例：

/graphdb/** 轉(zhuǎn)發(fā)到 Graph_Server/**

獲取轉(zhuǎn)發(fā)目的地址：

private String createRedictUrl(HttpServletRequest request, String routeUrl, String prefix) { String queryString = request.getQueryString(); return routeUrl + request.getRequestURI().replace(prefix, '') + (queryString != null ? '?' + queryString : ''); }

解析請求頭和內(nèi)容

然后從request中提取出header、body等內(nèi)容，構(gòu)造一個RequestEntity，后續(xù)可以用RestTemplate來請求。

private RequestEntity createRequestEntity(HttpServletRequest request, String url) throws URISyntaxException, IOException { String method = request.getMethod(); HttpMethod httpMethod = HttpMethod.resolve(method); MultiValueMap<String, String> headers = parseRequestHeader(request); byte[] body = parseRequestBody(request); return new RequestEntity<>(body, headers, httpMethod, new URI(url)); } private byte[] parseRequestBody(HttpServletRequest request) throws IOException { InputStream inputStream = request.getInputStream(); return StreamUtils.copyToByteArray(inputStream); } private MultiValueMap<String, String> parseRequestHeader(HttpServletRequest request) { HttpHeaders headers = new HttpHeaders(); List<String> headerNames = Collections.list(request.getHeaderNames()); for (String headerName : headerNames) { List<String> headerValues = Collections.list(request.getHeaders(headerName)); for (String headerValue : headerValues) { headers.add(headerName, headerValue); } } return headers; }

透明轉(zhuǎn)發(fā)

最后用RestTemplate來實現(xiàn)請求：

private ResponseEntity<String> route(RequestEntity requestEntity) { RestTemplate restTemplate = new RestTemplate(); return restTemplate.exchange(requestEntity, String.class); }

全部代碼

以下是輕量級轉(zhuǎn)發(fā)全部代碼：

import org.springframework.http.*;import org.springframework.stereotype.Service;import org.springframework.util.MultiValueMap;import org.springframework.util.StreamUtils;import org.springframework.web.client.RestTemplate;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;import java.io.InputStream;import java.net.URI;import java.net.URISyntaxException;import java.util.Collections;import java.util.List;@Servicepublic class RoutingDelegate { public ResponseEntity<String> redirect(HttpServletRequest request, HttpServletResponse response,String routeUrl, String prefix) { try { // build up the redirect URL String redirectUrl = createRedictUrl(request,routeUrl, prefix); RequestEntity requestEntity = createRequestEntity(request, redirectUrl); return route(requestEntity); } catch (Exception e) { return new ResponseEntity('REDIRECT ERROR', HttpStatus.INTERNAL_SERVER_ERROR); } } private String createRedictUrl(HttpServletRequest request, String routeUrl, String prefix) { String queryString = request.getQueryString(); return routeUrl + request.getRequestURI().replace(prefix, '') + (queryString != null ? '?' + queryString : ''); } private RequestEntity createRequestEntity(HttpServletRequest request, String url) throws URISyntaxException, IOException { String method = request.getMethod(); HttpMethod httpMethod = HttpMethod.resolve(method); MultiValueMap<String, String> headers = parseRequestHeader(request); byte[] body = parseRequestBody(request); return new RequestEntity<>(body, headers, httpMethod, new URI(url)); } private ResponseEntity<String> route(RequestEntity requestEntity) { RestTemplate restTemplate = new RestTemplate(); return restTemplate.exchange(requestEntity, String.class); } private byte[] parseRequestBody(HttpServletRequest request) throws IOException { InputStream inputStream = request.getInputStream(); return StreamUtils.copyToByteArray(inputStream); } private MultiValueMap<String, String> parseRequestHeader(HttpServletRequest request) { HttpHeaders headers = new HttpHeaders(); List<String> headerNames = Collections.list(request.getHeaderNames()); for (String headerName : headerNames) { List<String> headerValues = Collections.list(request.getHeaders(headerName)); for (String headerValue : headerValues) { headers.add(headerName, headerValue); } } return headers; }}

Spring 集成

Spring Controller,RequestMapping里把GET POSTPUTDELETE 支持的請求帶上，就能實現(xiàn)轉(zhuǎn)發(fā)了。

@RestController@RequestMapping(GraphDBController.DELEGATE_PREFIX)@Api(value = 'GraphDB', tags = { 'graphdb-Api'})public class GraphDBController { @Autowired GraphProperties graphProperties; public final static String DELEGATE_PREFIX = '/graphdb'; @Autowired private RoutingDelegate routingDelegate; @RequestMapping(value = '/**', method = {RequestMethod.GET, RequestMethod.POST, RequestMethod.PUT, RequestMethod.DELETE}, produces = MediaType.TEXT_PLAIN_VALUE) public ResponseEntity catchAll(HttpServletRequest request, HttpServletResponse response) { return routingDelegate.redirect(request, response, graphProperties.getGraphServer(), DELEGATE_PREFIX); }}

以上就是spring boot實現(xiàn)超輕量級網(wǎng)關(guān)（反向代理、轉(zhuǎn)發(fā)）的示例的詳細(xì)內(nèi)容，更多關(guān)于spring boot實現(xiàn)網(wǎng)關(guān)的資料請關(guān)注好吧啦網(wǎng)其它相關(guān)文章！