HttpServletRequest 在Filter中添加header

1、创建Wrapper

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.util.*;
 
/**
 * [ Filter请求拦截中添加header属性 ]
 *
 * @author Love丶TG
 * @version 1.0.0
 * @create 2019 年 11 月 22 日 11:44
 */
public class HeaderMapRequestWrapper extends HttpServletRequestWrapper {
 
    public HeaderMapRequestWrapper(HttpServletRequest request) {
        super(request);
    }
 
    private Map<String, String> headerMap = new HashMap<String, String>();
 
    public void addHeader(String name, String value) {
        headerMap.put(name, value);
    }
 
    @Override
    public String getHeader(String name) {
        String headerValue = super.getHeader(name);
        if (headerMap.containsKey(name)) {
            headerValue = headerMap.get(name);
        }
        return headerValue;
    }
 
    @Override
    public Enumeration<String> getHeaderNames() {
        List<String> names = Collections.list(super.getHeaderNames());
        for (String name : headerMap.keySet()) {
            names.add(name);
        }
        return Collections.enumeration(names);
    }
 
    @Override
    public Enumeration<String> getHeaders(String name) {
        List<String> values = Collections.list(super.getHeaders(name));
        if (headerMap.containsKey(name)) {
            values.add(headerMap.get(name));
        }
        return Collections.enumeration(values);
    }
}

2、通过上面这个类，然后简单在Filter中New对象使用即可。

public class RemoteAddrFilter implements Filter {

@Override
public void destroy() {

}

@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest) request;
HeaderMapRequestWrapper requestWrapper = new HeaderMapRequestWrapper(req);
//获得请求参数中的token值
String token = request.getParamter("token");
if（!StringUtils.isEntry(token)）{
//如果请求中带有这个参数，则进行过滤加一个header头
requestWrapper.addHeader("tokenr", token);
chain.doFilter(requestWrapper, response); // Goes to default servlet.
}
chain.doFilter(request, response); // Goes to default servlet.

}

@Override
public void init(FilterConfig filterConfig) throws ServletException {

}