如何給HttpServletRequest增加消息頭
HttpServletRequest增加header
由於在請求中請求域的屬性在請求轉發,路由等過程中,請求域的值會丟失,在項目項目中使用請求頭來傳遞信息,但是HttpRequest並沒有實現增加請求頭的方法,所以找到他的子類來實現
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); } }
使用:
public class SecurityFilter implements javax.servlet.Filter { @Override public void destroy() { } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { HttpServletRequest req = (HttpServletRequest) request; MutableHttpServletRequest mutableRequest = new MutableHttpServletRequest(req); ... mutableRequest.putHeader("x-custom-header", "custom value"); chain.doFilter(mutableRequest, response); } @Override public void init(FilterConfig filterConfig) throws ServletException { } }
但是項目中我使用的SpringCloud ZUUL中使用這樣 的方式失敗:
@Component public class AccessFilter extends ZuulFilter { private Logger log = LoggerFactory.getLogger(AccessFilter.class); @Autowired private VerificationHelper helper; private BufferedReader reader=null; @Autowired private KeyAndFrequencyService service; @Autowired private ZuulTest zuulTest; @Autowired private PermissionHandler permissionHandler; @Override public String filterType() { //前置過濾器 return "pre"; } @Override public int filterOrder() { //優先級,數字越大,優先級越低 return 0; } @Override public boolean shouldFilter() { //是否執行該過濾器,true代表需要過濾 return true; } @Override public Object run() { RequestContext ctx = RequestContext.getCurrentContext(); HttpServletRequest request = ctx.getRequest(); try { permissionHandler.setTokenExpireTime(200000000); String type = request.getHeader("type"); zuulTest.say(); System.out.println("......................................................"); if (type == null) { System.out.println("......................................................驗證1"); Object object = helper.AccessZuul(request, ctx); return object; } else { System.out.println("......................................................驗證2"); PermissionResult result=permissionHandler.check(request); System.out.println(result); if(result.isState()){ MutableHttpServletRequest mutRequest=new MutableHttpServletRequest (request); //增加頭部信息 DasAccountInfo accountInfo= permissionHandler.GetDasAccountInfoById(Integer.parseInt(result.getUserId())); mutRequest.putHeader("dasAccountInfo", JSON.toJSONString(disablePropertyName())) ;RequestContext.getCurrentContext().setRequest(mutRequest); ctx.setSendZuulResponse(true);// 對該請求進行路由 ctx.setResponseStatusCode(200); ctx.set("isSuccess", true); }else{ ctx.setSendZuulResponse(false);// 過濾該請求,不對其進行路由 ctx.setResponseStatusCode(401);// 返回錯誤碼 ctx.setResponseBody("{\"code\":0,\"result\":\"網關驗證失敗!驗證方式為2\"}");// 返回錯誤內容 ctx.set("isSuccess", false); } } }catch (Exception e){ e.printStackTrace(); log.error("網關報錯!!!",e.fillInStackTrace()); } return null; }
使用zuul網關的自帶的設置請求頭的方法,在網關中設置的請求頭可以被路由下面的服務獲取到:
ctx.getZuulRequestHeaders().put("dasAccountInfo", JSON.toJSONString(disablePropertyName()));
修改HttpServletRequest中header的信息
廢話一堆:由於業務有統一的鑒權系統,頁面請求時在header中帶過來gsid,正常業務沒有問題,但是當需要下載文件時,前端統一用json解析響應,當響應文件時,對於前端來說不好處理,就決定使用簡單的get請求下載文件,將gsid通過url帶過來,這樣的話後端鑒權就需要處理,當header中沒有gsid時,從參數中取,為瞭盡可能少的改變公用的業務代碼(指sso),就在當前項目中自定義權限攔截器。
總結一句,我就是想想header中加東西!!往下看具體實現方式:
新建攔截器類,繼承原有的攔截器,重寫其preHandle方法
@Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception { String gsid = request.getHeader("GSID"); if(StringUtils.isBlank(gsid)){ String gsid= request.getParameter("GSID"); //使用反射,將gsid設置到request中的的header中去 reflectSetparam(request,"GSID",gsid); log.info("請求連接中的gsid={}",request.getHeader("GSID")); } return super.preHandle(request, response, o); }
說明:可以看到在方法中,
1、先進行header信息判斷,如果header中沒有GSID,就去請求參數中拿
gsid= request.getParameter("GSID");
2、通過反射將參數中的GSID鍵值對兒:“GSID”:“376645354562335”加入到header中去
話不多少,先上代碼,再解釋:
解釋:
/** * 修改header信息,key-value鍵值對兒加入到header中 * @param request * @param key * @param value */ private void reflectSetparam(HttpServletRequest request,String key,String value){ Class<? extends HttpServletRequest> requestClass = request.getClass(); System.out.println("request實現類="+requestClass.getName()); try { Field request1 = requestClass.getDeclaredField("request"); request1.setAccessible(true); Object o = request1.get(request); Field coyoteRequest = o.getClass().getDeclaredField("coyoteRequest"); coyoteRequest.setAccessible(true); Object o1 = coyoteRequest.get(o); System.out.println("coyoteRequest實現類="+o1.getClass().getName()); Field headers = o1.getClass().getDeclaredField("headers"); headers.setAccessible(true); MimeHeaders o2 = (MimeHeaders)headers.get(o1); o2.addValue(key).setString(value); } catch (Exception e) { e.printStackTrace(); } }
執行打印信息如下:
request實現類=org.apache.catalina.connector.RequestFacade
coyoteRequest實現類=org.apache.coyote.Request
看HttpServletRequest的源碼,是個接口,並且我們獲取header信息的方法是getHeader()方法,按常理其對象中應該有header字段,那麼我們就去實現類中找這個字段,具體過程如下
步驟一:先找到具體的Request對象是哪個類,根據打印信息看源碼
進入其中找到getHeader()方法,如下
public String getHeader(String name) { if (this.request == null) { throw new IllegalStateException(sm.getString("requestFacade.nullRequest")); } else { return this.request.getHeader(name); } }
然後我們找this.request
這個request,我們找到它的類型,點擊去
這個類的全路徑是:org.apache.catalina.connector.Request
這個類中找getHeader方法
public String getHeader(String name) { return this.coyoteRequest.getHeader(name); }
找到這個類中的coyoteRequest
protected org.apache.coyote.Request coyoteRequest;
是這樣的
再找到getHeader()
public String getHeader(String name) { return this.headers.getHeader(name); }
好瞭,終於見到屬性瞭
private final MimeHeaders headers = new MimeHeaders();
找到MineHeaders中的getHeader方法,
public String getHeader(String name) { MessageBytes mh = this.getValue(name); return mh != null ? mh.toString() : null; }
看到最終header是一個MessageBytes對象,好找到這個對象進去,發現隻能setValue,那就在MineHeaders中找在哪裡實例化MessageBytes對象的
找瞭半天找到在createHeader()方法中實例化MimeHeaderField對象,然後這個對象實例化時會實例化MessageBytes對象
這裡有name,value,靠譜
然後再在MimeHeader中找在addValue方法中有調用,就用這個試一下吧,然後就是最上面的我自定義的方法,在heade中加入瞭一個鍵值對兒。
測試請求:
http://127.0.0.1:32100/v1/CustomerRefundRest/exportRefund?gsid=abc114f1bd0d484084e5df3fe1c419b8&refundLongStartDate=1520611199000&refundLongEndDate=1522943999000
測試打印結果:
OVER!以上為個人經驗,希望能給大傢一個參考,也希望大傢多多支持WalkonNet。
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