自己動手寫一個服務網關
原文鏈接：https://www.cnblogs.com/bigben0123/p/9252444.html
引言
什么是網關？為什么需要使用網關？
如圖所示，在不使用網關的情況下，我們的服務是直接暴露給服務調用方。當調用方增多，勢必需要添加定制化訪問權限、校驗等邏輯。當添加API網關后，再第三方調用端和服務提供方之間就創建了一面牆，這面牆直接與調用方通信進行權限控制。
本文所實現的網關源碼抄襲了---Oh,不對，是借鑒。借鑒了Zuul網關的源碼，提煉出其核心思路，實現了一套簡單的網關源碼，博主將其改名為Eatuul。
題外話
本文是業內能搜到的第一篇自己動手實現網關的文章。博主寫的手把手系列的文章，目的是在以最簡單的方式，揭露出中間件的核心原理，讓讀者能夠迅速了解實現的核心。需要說明的是，這不是源碼分析系列的文章，因此寫出來的代碼，省去了一些復雜的內容，畢竟大家能理解到該中間件的核心原理即可。如果想看源碼分析系列的，請關注博主，后期會將spring、spring boot、dubbo、mybatis等開源框架一一揭示。
正文
設計思路
先大致說一下，就是定義一個Servlet接收請求。然后經過preFilter(封裝請求參數),routeFilter(轉發請求)，postFilter(輸出內容)。三個過濾器之間，共享request、response以及其他的一些全局變量。如下圖所示
和真正的Zuul的區別?
主要區別有如下幾點
(1)Zuul中在異常處理模塊，有一個ErrorFilter來處理，博主在實現的時候偷懶了，略去。
(2)Zuul中PreFilters,RoutingFilters,PostFilters默認都實現了一組，具體如下表所示：
博主總不可能每一個都給你們實現一遍吧。所以偷懶了，每種只實現一個。但是調用順序還是不變，按照PreFilters->RoutingFilters->PostFilters的順序調用。
(3)在routeFilters確實有轉發請求的Filter,然而博主偷天換日了，改用RestTemplate實現。
代碼結構
大家去spring官網上搭建一套springboot的項目，博主就不展示pom的代碼了。直接將項目結構展示一下，如下圖所示
EatuulServlet.java
這個是網關的入口，邏輯也十分簡單，分為三步
(1)將request,response放入threadlocal中
(2)執行三組過濾器
(3)清除threadlocal中的的環境變量
源碼如下
package com.rjzheng.eatuul.http;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet(name = "eatuul", urlPatterns = "/*")
public class EatuulServlet extends HttpServlet {
private EatRunner eatRunner = new EatRunner();
@Override public void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//將request，和response放入上下文對象中 eatRunner.init(req, resp);
try { //執行前置過濾 eatRunner.preRoute(); //執行過濾 eatRunner.route(); //執行后置過濾 eatRunner.postRoute(); } catch (Throwable e) {
RequestContext.getCurrentContext().getResponse() .sendError(HttpServletResponse.SC_NOT_FOUND, e.getMessage()); } finally {
//清除變量 RequestContext.getCurrentContext().unset(); } } }EatuulRunner.java
這個是具體的執行器。需要說明一下，在Zuul中，ZuulRunner在獲取具體有哪些過濾器的時候，有一個FileLoader可以動態讀取配置加載。博主在實現我們自己的EatuulRunner時候，略去動態讀取的過程，直接靜態寫死。
源碼如下
package com.rjzheng.eatuul.http;
import java.util.ArrayList;import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.rjzheng.eatuul.filter.EatuulFilter;
import com.rjzheng.eatuul.filter.post.SendResponseFilter;
import com.rjzheng.eatuul.filter.pre.RequestWrapperFilter;
import com.rjzheng.eatuul.filter.route.RoutingFilter;
public class EatRunner {
//靜態寫死過濾器 private ConcurrentHashMap<String, List<EatuulFilter>> hashFiltersByType = new ConcurrentHashMap<String, List<EatuulFilter>>(){{ put("pre",new ArrayList<EatuulFilter>(){{ add(new RequestWrapperFilter()); }}); put("route",new ArrayList<EatuulFilter>(){{ add(new RoutingFilter()); }}); put("post",new ArrayList<EatuulFilter>(){{ add(new SendResponseFilter()); }}); }};
public void init(HttpServletRequest req, HttpServletResponse resp) { RequestContext ctx = RequestContext.getCurrentContext(); ctx.setRequest(req); ctx.setResponse(resp); } public void preRoute() throws Throwable { runFilters("pre"); } public void route() throws Throwable{ runFilters("route"); } public void postRoute() throws Throwable{ runFilters("post"); }
public void runFilters(String sType) throws Throwable { List<EatuulFilter> list = this.hashFiltersByType.get(sType); if (list != null) {
for (int i = 0; i < list.size(); i++) { EatuulFilter zuulFilter = list.get(i); zuulFilter.run(); } } } }EatuulFilter.java
接下來就是一系列Filter的代碼了，先上父類EatuulFilter的源碼
package com.rjzheng.eatuul.filter;
public abstract class EatuulFilter {
abstract public String filterType();
abstract public int filterOrder();
abstract public void run(); }RequestWrapperFilter.java
這個是PreFilter,前置執行過濾器，負責封裝請求。步驟如下所示
(1)封裝請求頭
(2)封裝請求體
(3)構造出RestTemplate能識別的RequestEntity
(4)將RequestEntity放入全局threadlocal之中
代碼如下所示
package com.rjzheng.eatuul.filter.pre;
import java.io.IOException;import java.io.InputStream;
import java.net.URI;import java.net.URISyntaxException;
import java.util.Collections;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.RequestEntity;
import org.springframework.util.MultiValueMap;
import org.springframework.util.StreamUtils;
import com.rjzheng.eatuul.filter.EatuulFilter;
import com.rjzheng.eatuul.http.RequestContext;
public class RequestWrapperFilter extends EatuulFilter{
@Override public String filterType() {
// TODO Auto-generated method stub return "pre"; }
@Override public int filterOrder() {
// TODO Auto-generated method stub return -1; }
@Override public void run() { String rootURL = "http://localhost:9090"; RequestContext ctx =RequestContext.getCurrentContext(); HttpServletRequest servletRequest = ctx.getRequest(); String targetURL = rootURL + servletRequest.getRequestURI(); RequestEntity<byte[]> requestEntity = null; try { requestEntity = createRequestEntity(servletRequest, targetURL); } catch (Exception e) { e.printStackTrace(); } //4、將requestEntity放入全局threadlocal之中 ctx.setRequestEntity(requestEntity); }
private RequestEntity createRequestEntity(HttpServletRequest request,String url) throws URISyntaxException, IOException { String method = request.getMethod(); HttpMethod httpMethod = HttpMethod.resolve(method); //1、封裝請求頭 MultiValueMap<String, String> headers =createRequestHeaders(request); //2、封裝請求體 byte[] body = createRequestBody(request); //3、構造出RestTemplate能識別的RequestEntity RequestEntity requestEntity = new RequestEntity<byte[]>(body,headers,httpMethod, new URI(url)); return requestEntity; } private byte[] createRequestBody(HttpServletRequest request) throws IOException { InputStream inputStream = request.getInputStream(); return StreamUtils.copyToByteArray(inputStream); }
private MultiValueMap<String, String> createRequestHeaders(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; } }RoutingFilter.java
這個是routeFilter,這里我偷懶了，直接做轉發請求，並且將返回值ResponseEntity放入全局threadlocal中
package com.rjzheng.eatuul.filter.route;
import org.springframework.http.RequestEntity;
import org.springframework.http.ResponseEntity;
import org.springframework.web.client.RestTemplate;
import com.rjzheng.eatuul.filter.EatuulFilter;
import com.rjzheng.eatuul.http.RequestContext; public class RoutingFilter extends EatuulFilter{ @Override public String filterType() {
// TODO Auto-generated method stub return "route"; } @Override public int filterOrder() {
// TODO Auto-generated method stub return 0; } @Override public void run(){
RequestContext ctx = RequestContext.getCurrentContext();
RequestEntity requestEntity = ctx.getRequestEntity();
RestTemplate restTemplate = new RestTemplate();
ResponseEntity responseEntity = restTemplate.exchange(requestEntity,byte[].class); ctx.setResponseEntity(responseEntity); } }SendResponseFilter.java
這個是postFilters,將ResponseEntity輸出即可
package com.rjzheng.eatuul.filter.post;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import org.springframework.http.HttpHeaders;
import org.springframework.http.ResponseEntity;
import com.rjzheng.eatuul.filter.EatuulFilter;
import com.rjzheng.eatuul.http.RequestContext;
public class SendResponseFilter extends EatuulFilter{
@Override public String filterType() {
return "post"; }
@Override public int filterOrder() {
return 1000; }
@Override public void run() {
try { addResponseHeaders(); writeResponse(); } catch (Exception e) { e.printStackTrace(); } }
private void addResponseHeaders() { RequestContext ctx = RequestContext.getCurrentContext(); HttpServletResponse servletResponse = ctx.getResponse(); ResponseEntity responseEntity = ctx.getResponseEntity(); HttpHeaders httpHeaders = responseEntity.getHeaders();
for(Map.Entry<String, List<String>> entry:httpHeaders.entrySet()){ String headerName = entry.getKey(); List<String> headerValues = entry.getValue(); for(String headerValue:headerValues) { servletResponse.addHeader(headerName, headerValue); } } }
private void writeResponse()throws Exception { RequestContext ctx = RequestContext.getCurrentContext(); HttpServletResponse servletResponse = ctx.getResponse();
if (servletResponse.getCharacterEncoding() == null) {
// only set if not set servletResponse.setCharacterEncoding("UTF-8"); } ResponseEntity responseEntity = ctx.getResponseEntity();
if(responseEntity.hasBody()) {
byte[] body = (byte[]) responseEntity.getBody(); ServletOutputStream outputStream = servletResponse.getOutputStream(); outputStream.write(body); outputStream.flush(); } } }RequestContext.java
最后是一直在說的全局threadlocal變量
package com.rjzheng.eatuul.http;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.http.RequestEntity;
import org.springframework.http.ResponseEntity;
public class RequestContext extends ConcurrentHashMap<String, Object> { protected static Class<? extends RequestContext> contextClass = RequestContext.class;
protected static final ThreadLocal<? extends RequestContext> threadLocal = new ThreadLocal<RequestContext>() {
@Override protected RequestContext initialValue() {
try {
return contextClass.newInstance();
} catch (Throwable e) {
throw new RuntimeException(e); } } };
public static RequestContext getCurrentContext() { RequestContext context = threadLocal.get();
return context; }
public HttpServletRequest getRequest() {
return (HttpServletRequest) get("request"); }
public void setRequest(HttpServletRequest request) { put("request", request); }
public HttpServletResponse getResponse() {
return (HttpServletResponse) get("response"); }
public void setResponse(HttpServletResponse response) { set("response", response); }
public void setRequestEntity(RequestEntity requestEntity){ set("requestEntity",requestEntity); }
public RequestEntity getRequestEntity() {
return (RequestEntity) get("requestEntity"); }
public void setResponseEntity(ResponseEntity responseEntity){ set("responseEntity",responseEntity); }
public ResponseEntity getResponseEntity() {
return (ResponseEntity) get("responseEntity"); }
public void set(String key, Object value) {
if (value != null) put(key, value);
else remove(key); }
public void unset() { threadLocal.remove(); } }如何測試？
自己另外起一個server端口為9090如下所示
package com.rjzheng.eatservice;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.ServletComponentScan;
import com.rjzheng.eatservice.controller.IndexController;
@SpringBootApplication@ServletComponentScan(basePackageClasses = IndexController.class)
public class Application { public static void main(String[] args) {
new SpringApplicationBuilder(Application.class).
properties("server.port=9090").run(args); } }再來一個controller
package com.rjzheng.eatservice.controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController; @RestController
public class IndexController { @RequestMapping("/index") public String index() {
return "hello!world"; } }然后，你就發現可以從localhost:8080/index進行跳轉訪問了。
引言
什么是網關？為什么需要使用網關？
如圖所示，在不使用網關的情況下，我們的服務是直接暴露給服務調用方。當調用方增多，勢必需要添加定制化訪問權限、校驗等邏輯。當添加API網關后，再第三方調用端和服務提供方之間就創建了一面牆，這面牆直接與調用方通信進行權限控制。
本文所實現的網關源碼抄襲了---Oh,不對，是借鑒。借鑒了Zuul網關的源碼，提煉出其核心思路，實現了一套簡單的網關源碼，博主將其改名為Eatuul。
題外話
本文是業內能搜到的第一篇自己動手實現網關的文章。博主寫的手把手系列的文章，目的是在以最簡單的方式，揭露出中間件的核心原理，讓讀者能夠迅速了解實現的核心。需要說明的是，這不是源碼分析系列的文章，因此寫出來的代碼，省去了一些復雜的內容，畢竟大家能理解到該中間件的核心原理即可。如果想看源碼分析系列的，請關注博主，后期會將spring、spring boot、dubbo、mybatis等開源框架一一揭示。
正文
設計思路
先大致說一下，就是定義一個Servlet接收請求。然后經過preFilter(封裝請求參數),routeFilter(轉發請求)，postFilter(輸出內容)。三個過濾器之間，共享request、response以及其他的一些全局變量。如下圖所示
和真正的Zuul的區別?
主要區別有如下幾點
(1)Zuul中在異常處理模塊，有一個ErrorFilter來處理，博主在實現的時候偷懶了，略去。
(2)Zuul中PreFilters,RoutingFilters,PostFilters默認都實現了一組，具體如下表所示：
博主總不可能每一個都給你們實現一遍吧。所以偷懶了，每種只實現一個。但是調用順序還是不變，按照PreFilters->RoutingFilters->PostFilters的順序調用。
(3)在routeFilters確實有轉發請求的Filter,然而博主偷天換日了，改用RestTemplate實現。
代碼結構
大家去spring官網上搭建一套springboot的項目，博主就不展示pom的代碼了。直接將項目結構展示一下，如下圖所示
EatuulServlet.java
這個是網關的入口，邏輯也十分簡單，分為三步
(1)將request,response放入threadlocal中
(2)執行三組過濾器
(3)清除threadlocal中的的環境變量
源碼如下
package com.rjzheng.eatuul.http;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet(name = "eatuul", urlPatterns = "/*")
public class EatuulServlet extends HttpServlet {
private EatRunner eatRunner = new EatRunner();
@Override public void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//將request，和response放入上下文對象中 eatRunner.init(req, resp);
try { //執行前置過濾 eatRunner.preRoute(); //執行過濾 eatRunner.route(); //執行后置過濾 eatRunner.postRoute(); } catch (Throwable e) {
RequestContext.getCurrentContext().getResponse() .sendError(HttpServletResponse.SC_NOT_FOUND, e.getMessage()); } finally {
//清除變量 RequestContext.getCurrentContext().unset(); } } }EatuulRunner.java
這個是具體的執行器。需要說明一下，在Zuul中，ZuulRunner在獲取具體有哪些過濾器的時候，有一個FileLoader可以動態讀取配置加載。博主在實現我們自己的EatuulRunner時候，略去動態讀取的過程，直接靜態寫死。
源碼如下
package com.rjzheng.eatuul.http;
import java.util.ArrayList;import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.rjzheng.eatuul.filter.EatuulFilter;
import com.rjzheng.eatuul.filter.post.SendResponseFilter;
import com.rjzheng.eatuul.filter.pre.RequestWrapperFilter;
import com.rjzheng.eatuul.filter.route.RoutingFilter;
public class EatRunner {
//靜態寫死過濾器 private ConcurrentHashMap<String, List<EatuulFilter>> hashFiltersByType = new ConcurrentHashMap<String, List<EatuulFilter>>(){{ put("pre",new ArrayList<EatuulFilter>(){{ add(new RequestWrapperFilter()); }}); put("route",new ArrayList<EatuulFilter>(){{ add(new RoutingFilter()); }}); put("post",new ArrayList<EatuulFilter>(){{ add(new SendResponseFilter()); }}); }};
public void init(HttpServletRequest req, HttpServletResponse resp) { RequestContext ctx = RequestContext.getCurrentContext(); ctx.setRequest(req); ctx.setResponse(resp); } public void preRoute() throws Throwable { runFilters("pre"); } public void route() throws Throwable{ runFilters("route"); } public void postRoute() throws Throwable{ runFilters("post"); }
public void runFilters(String sType) throws Throwable { List<EatuulFilter> list = this.hashFiltersByType.get(sType); if (list != null) {
for (int i = 0; i < list.size(); i++) { EatuulFilter zuulFilter = list.get(i); zuulFilter.run(); } } } }EatuulFilter.java
接下來就是一系列Filter的代碼了，先上父類EatuulFilter的源碼
package com.rjzheng.eatuul.filter;
public abstract class EatuulFilter {
abstract public String filterType();
abstract public int filterOrder();
abstract public void run(); }RequestWrapperFilter.java
這個是PreFilter,前置執行過濾器，負責封裝請求。步驟如下所示
(1)封裝請求頭
(2)封裝請求體
(3)構造出RestTemplate能識別的RequestEntity
(4)將RequestEntity放入全局threadlocal之中
代碼如下所示
package com.rjzheng.eatuul.filter.pre;
import java.io.IOException;import java.io.InputStream;
import java.net.URI;import java.net.URISyntaxException;
import java.util.Collections;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.RequestEntity;
import org.springframework.util.MultiValueMap;
import org.springframework.util.StreamUtils;
import com.rjzheng.eatuul.filter.EatuulFilter;
import com.rjzheng.eatuul.http.RequestContext;
public class RequestWrapperFilter extends EatuulFilter{
@Override public String filterType() {
// TODO Auto-generated method stub return "pre"; }
@Override public int filterOrder() {
// TODO Auto-generated method stub return -1; }
@Override public void run() { String rootURL = "http://localhost:9090"; RequestContext ctx =RequestContext.getCurrentContext(); HttpServletRequest servletRequest = ctx.getRequest(); String targetURL = rootURL + servletRequest.getRequestURI(); RequestEntity<byte[]> requestEntity = null; try { requestEntity = createRequestEntity(servletRequest, targetURL); } catch (Exception e) { e.printStackTrace(); } //4、將requestEntity放入全局threadlocal之中 ctx.setRequestEntity(requestEntity); }
private RequestEntity createRequestEntity(HttpServletRequest request,String url) throws URISyntaxException, IOException { String method = request.getMethod(); HttpMethod httpMethod = HttpMethod.resolve(method); //1、封裝請求頭 MultiValueMap<String, String> headers =createRequestHeaders(request); //2、封裝請求體 byte[] body = createRequestBody(request); //3、構造出RestTemplate能識別的RequestEntity RequestEntity requestEntity = new RequestEntity<byte[]>(body,headers,httpMethod, new URI(url)); return requestEntity; } private byte[] createRequestBody(HttpServletRequest request) throws IOException { InputStream inputStream = request.getInputStream(); return StreamUtils.copyToByteArray(inputStream); }
private MultiValueMap<String, String> createRequestHeaders(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; } }RoutingFilter.java
這個是routeFilter,這里我偷懶了，直接做轉發請求，並且將返回值ResponseEntity放入全局threadlocal中
package com.rjzheng.eatuul.filter.route;
import org.springframework.http.RequestEntity;
import org.springframework.http.ResponseEntity;
import org.springframework.web.client.RestTemplate;
import com.rjzheng.eatuul.filter.EatuulFilter;
import com.rjzheng.eatuul.http.RequestContext; public class RoutingFilter extends EatuulFilter{ @Override public String filterType() {
// TODO Auto-generated method stub return "route"; } @Override public int filterOrder() {
// TODO Auto-generated method stub return 0; } @Override public void run(){
RequestContext ctx = RequestContext.getCurrentContext();
RequestEntity requestEntity = ctx.getRequestEntity();
RestTemplate restTemplate = new RestTemplate();
ResponseEntity responseEntity = restTemplate.exchange(requestEntity,byte[].class); ctx.setResponseEntity(responseEntity); } }SendResponseFilter.java
這個是postFilters,將ResponseEntity輸出即可
package com.rjzheng.eatuul.filter.post;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import org.springframework.http.HttpHeaders;
import org.springframework.http.ResponseEntity;
import com.rjzheng.eatuul.filter.EatuulFilter;
import com.rjzheng.eatuul.http.RequestContext;
public class SendResponseFilter extends EatuulFilter{
@Override public String filterType() {
return "post"; }
@Override public int filterOrder() {
return 1000; }
@Override public void run() {
try { addResponseHeaders(); writeResponse(); } catch (Exception e) { e.printStackTrace(); } }
private void addResponseHeaders() { RequestContext ctx = RequestContext.getCurrentContext(); HttpServletResponse servletResponse = ctx.getResponse(); ResponseEntity responseEntity = ctx.getResponseEntity(); HttpHeaders httpHeaders = responseEntity.getHeaders();
for(Map.Entry<String, List<String>> entry:httpHeaders.entrySet()){ String headerName = entry.getKey(); List<String> headerValues = entry.getValue(); for(String headerValue:headerValues) { servletResponse.addHeader(headerName, headerValue); } } }
private void writeResponse()throws Exception { RequestContext ctx = RequestContext.getCurrentContext(); HttpServletResponse servletResponse = ctx.getResponse();
if (servletResponse.getCharacterEncoding() == null) {
// only set if not set servletResponse.setCharacterEncoding("UTF-8"); } ResponseEntity responseEntity = ctx.getResponseEntity();
if(responseEntity.hasBody()) {
byte[] body = (byte[]) responseEntity.getBody(); ServletOutputStream outputStream = servletResponse.getOutputStream(); outputStream.write(body); outputStream.flush(); } } }RequestContext.java
最后是一直在說的全局threadlocal變量
package com.rjzheng.eatuul.http;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.http.RequestEntity;
import org.springframework.http.ResponseEntity;
public class RequestContext extends ConcurrentHashMap<String, Object> { protected static Class<? extends RequestContext> contextClass = RequestContext.class;
protected static final ThreadLocal<? extends RequestContext> threadLocal = new ThreadLocal<RequestContext>() {
@Override protected RequestContext initialValue() {
try {
return contextClass.newInstance();
} catch (Throwable e) {
throw new RuntimeException(e); } } };
public static RequestContext getCurrentContext() { RequestContext context = threadLocal.get();
return context; }
public HttpServletRequest getRequest() {
return (HttpServletRequest) get("request"); }
public void setRequest(HttpServletRequest request) { put("request", request); }
public HttpServletResponse getResponse() {
return (HttpServletResponse) get("response"); }
public void setResponse(HttpServletResponse response) { set("response", response); }
public void setRequestEntity(RequestEntity requestEntity){ set("requestEntity",requestEntity); }
public RequestEntity getRequestEntity() {
return (RequestEntity) get("requestEntity"); }
public void setResponseEntity(ResponseEntity responseEntity){ set("responseEntity",responseEntity); }
public ResponseEntity getResponseEntity() {
return (ResponseEntity) get("responseEntity"); }
public void set(String key, Object value) {
if (value != null) put(key, value);
else remove(key); }
public void unset() { threadLocal.remove(); } }如何測試？
自己另外起一個server端口為9090如下所示
package com.rjzheng.eatservice;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.ServletComponentScan;
import com.rjzheng.eatservice.controller.IndexController;
@SpringBootApplication@ServletComponentScan(basePackageClasses = IndexController.class)
public class Application { public static void main(String[] args) {
new SpringApplicationBuilder(Application.class).
properties("server.port=9090").run(args); } }再來一個controller
package com.rjzheng.eatservice.controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController; @RestController
public class IndexController { @RequestMapping("/index") public String index() {
return "hello!world"; } }然后，你就發現可以從localhost:8080/index進行跳轉訪問了。