通过过滤器向请求添加自定义标头

本文介绍了通过过滤器向请求添加自定义标头的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有一个扩展Filter类的类，它看起来像:

I have a class which extend Filter class and it looks like:

@Component @Order(Ordered.HIGHEST_PRECEDENCE) public class CorsFilter implements Filter { @Override public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException { System.out.println("--------------------------------------"); HttpServletRequest request = (HttpServletRequest) req; req.setAttribute("test", "test"); final HttpServletResponse response = (HttpServletResponse) res; response.setHeader("Access-Control-Allow-Origin", "*"); response.setHeader("Access-Control-Allow-Methods", "POST, PUT, GET, OPTIONS, DELETE"); response.setHeader("Access-Control-Allow-Headers", "Authorization, Content-Type"); response.setHeader("Access-Control-Max-Age", "3600"); if ("OPTIONS".equalsIgnoreCase(((HttpServletRequest) req).getMethod())) { response.setStatus(HttpServletResponse.SC_OK); } else { chain.doFilter(req, res); } }

问题是我可以向request添加自定义header吗?我经历了request和req内部可用的所有方法，找不到任何方法.但是在debug模式下，我发现CoyoteRequest内是headers的列表.如何在其中添加自定义header?

The question is can I add a custom header to request? I went through all method which are available inside request and req and couldn't find any way. But in debug mode I found that inside CoyoteRequest is list of headers. How can I add there my custom header?

推荐答案

您不能在HttpServletRequest对象中设置标头，但可以使用包装器类.

You can not set the headers in HttpServletRequestobject, but you can use a wrapper class.

请参阅本指南: wilddiary/adding-custom- headers-java-httpservletrequest/

以防万一将来链接无效:

Just in case for future the link becomes invalid:

final 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); } }

用法:

@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); }