HttpServletRequest增加消息头

由于在请求中请求域的属性在请求转发，路由等过程中，请求域的值会丢失，，在项目项目中使用请求头来传递信息，但是HttpRequest并没有实现增加请求头的方法，所以找到他的子类来实现

 
class MutableHttpServletRequest extends HttpServletRequestWrapper {
    // holds custom header and value mapping
    private final Map customHeaders;
 
    public MutableHttpServletRequest(HttpServletRequest request){
        super(request);
        this.customHeaders = new HashMap();
    }
    
    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 getHeaderNames() {
        // create a set of the custom header names
        Set set = new HashSet(customHeaders.keySet());
        
        // now add the headers from the wrapped request object
        @SuppressWarnings("unchecked")
        Enumeration 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 {
        
    }
}

但是项目中我使用的SpringCloud ZUUL中使用这样 的方式失败：

@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() {
        //前置过滤器
        return "pre";
    }

    @Override
    public int filterOrder() {
        //优先级，数字越大，优先级越低
        return 0;
    }

    @Override
    public boolean shouldFilter() {
        //是否执行该过滤器，true代表需要过滤
        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("......................................................验证1");

                Object object = helper.AccessZuul(request, ctx);
                return object;


            } else {

                System.out.println("......................................................验证2");





                PermissionResult result=permissionHandler.check(request);
                System.out.println(result);
                if(result.isState()){



          
MutableHttpServletRequest  mutRequest=new MutableHttpServletRequest (request)；
                     //增加头部信息
                    DasAccountInfo accountInfo= permissionHandler.GetDasAccountInfoById(Integer.parseInt(result.getUserId()));
                    
                    mutRequest.putHeader("dasAccountInfo", JSON.toJSONString(disablePropertyName()))                   ;RequestContext.getCurrentContext().setRequest(mutRequest);


                    ctx.setSendZuulResponse(true);// 对该请求进行路由
                    ctx.setResponseStatusCode(200);
                    ctx.set("isSuccess", true);

                }else{
                    ctx.setSendZuulResponse(false);// 过滤该请求，不对其进行路由
                    ctx.setResponseStatusCode(401);// 返回错误码
                    ctx.setResponseBody("{\"code\":0,\"result\":\"网关验证失败!验证方式为2\"}");// 返回错误内容
                    ctx.set("isSuccess", false);
                }

            }

        }catch (Exception e){
            e.printStackTrace();
            log.error("网关报错！！！",e.fillInStackTrace());
        }

           return null;
    }

使用zuul网关的自带的设置请求头的方法，在网关中设置的请求头可以被路由下面的服务获取到:

ctx.getZuulRequestHeaders().put("dasAccountInfo", JSON.toJSONString(disablePropertyName()));

参考：
https://blog.csdn.net/wangjia55/article/details/51712574/