场景：过滤器中获取参数Token并添加到请求头（用户认证兼容老系统）
请求头和请求参数是不能直接修改，也没有提供修改的方法，但是可以在过滤器和拦截器中使用HttpServletRequestWrapper包装类达到修改的目的。
一、实现HttpServletRequestWrapper接口，下面直接使用匿名类
package com.xxxx.web.filter;
import org.apache.commons.lang3.StringUtils;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.IOException;
import java.util.Enumeration;
@WebFilter
public class AuthHeaderSettingFilter implements Filter{
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
HttpServletRequestWrapper requestWrapper = new HttpServletRequestWrapper((HttpServletRequest) request) {
/**
* 当调用request.getHeader("token")时，则获取请求参数中token值并当做Header的值返回
* @param name
* @return
*/
@Override
public String getHeader(String name) {
// 先从原本的Request中获取头，如果为空且名字为token，则从参数中查找并返回
String superHeader = super.getHeader(name);
if("token".equals(name) && StringUtils.isEmpty(superHeader)){
String token = request.getParameter("token");
if (StringUtils.isNotEmpty(token)) {
return token ;
}
}
return superHeader;
}
};
chain.doFilter(requestWrapper,response);
}
@Override
public void destroy() {
}
}
二、HttpServletRequestWrapper、ServletRequestWrapper和HttpServletRequest接口中的很多方法都可以重写
- 要想增加一个请求参数可以在
HttpServletRequestWrapper中重写getParameter(String name)
@Override
public String getParameter(String name) {
if("newParam".equals(name)){
return "这是我新增加的参数";
}
return super.getParameter(name);
}
@Override
public Map<String, String[]> getParameterMap() {
HashMap<String, String[]> newMap = new HashMap<>();
newMap.putAll(super.getParameterMap());
newMap.put("newParam",new String[]{"这是我新增加的参数"}) ;
return Collections.unmodifiableMap(newMap);
}
@Override
public String[] getParameterValues(String name) {
if("newParam".equals(name)){
return new String[]{"这是我新增加的参数"};
}
return super.getParameterValues(name);
}
注意：
getParameterMap()返回的时一个不可修改的map ,不能直接向里面put值， 所以在重写这个方法时要自己new 一个HashMap ，然后在新建的map中放值，最后返回时必须调用Collections.unmodifiableMap(Map<? extends K, ? extends V> m)把map改成不可变的
-
结构
image.png
image.png
参考：
- Safely add / modify Servlet request parameter values -- 可能要代理才能访问
作者：else05
链接：https://www.jianshu.com/p/a8c9d45775ea
来源：简书
简书著作权归作者所有，任何形式的转载都请联系作者获得授权并注明出处。
背景
由于环境升级，需要重新设置header中的 一个值，暂设定为 org . http 请求时加入在header中加入org,但在filter中，会通过验证，生成新的org，需要覆盖原来header中的org.
修改 filter 。代码是在网上找的一部分，根据自己的需要进行调整了。
@Component
@Slf4j
@WebFilter(urlPatterns = { "/" }, filterName = "authorFilter")
public class DemoFilter implements Filter {
@Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse,
FilterChain filterChain) throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest) servletRequest;
req.setAttribute("hdd","tttt");
HeaderMapRequestWrapper requestWrapper = new HeaderMapRequestWrapper(req);
requestWrapper.addHeader("realm","test");
log.info("header-->{}",getHeadKeyAndValue(req));
filterChain.doFilter(requestWrapper, servletResponse);
}
private Map<String, String> getHeadKeyAndValue(HttpServletRequest httpRequest) {
Map<String, String> header = new HashMap<>();
Enumeration<String> headerNames = httpRequest.getHeaderNames();
while (headerNames.hasMoreElements()) {
String nextElement = headerNames.nextElement();
header.put(nextElement, httpRequest.getHeader(nextElement));
}
return header;
}
}
@Slf4j
public class HeaderMapRequestWrapper extends HttpServletRequestWrapper {
/**
* construct a wrapper for this request
*
* @param request
*/
public HeaderMapRequestWrapper(HttpServletRequest request) {
super(request);
}
private Map<String, String> headerMap = new HashMap<>();
/**
* add a header with given name and value
*
* @param name
* @param value
*/
public void addHeader(String name, String value) {
headerMap.put(name, value);
}
@Override
public String getHeader(String name) {
log.info("getHeader --->{}",name);
String headerValue = super.getHeader(name);
if (headerMap.containsKey(name)) {
headerValue = headerMap.get(name);
}
return headerValue;
}
/**
* get the Header names
*/
@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) {
log.info("getHeaders --->>>>>>{}",name);
List<String> values = Collections.list(super.getHeaders(name));
log.info("getHeaders --->>>>>>{}",values);
if (headerMap.containsKey(name)) {
log.info("getHeaders --->{}",headerMap.get(name));
values = Arrays.asList(headerMap.get(name));
}
return Collections.enumeration(values);
}
}
经过测试，在header解析时，是通过getHeaders方法，这个地方原来的时候是通过，values直接添加新的header,组成了一个 header的数组，而不是覆盖。
https://www.liangzl.com/get-article-detail-35965.html
HttpServletRequest修改/添加header和cookie参数
实现功能：
所有接口经过过滤器，获取每个接口的自定义头部(token)
判断如果是app访问，则给头部设置cookie，值为自定义token的值。
即：使用过滤器实现修改请求头headers
实现步骤：
1.自定义过滤器 ModifyParametersFilter.java 并继承 OncePerRequestFilter
package com.mobile.web.common;
import org.springframework.web.filter.OncePerRequestFilter;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.*;
/**
* 自定义的过滤器,
* Created by Administrator on 2017/6/19 0019.
*/
public class ModifyParametersFilter extends OncePerRequestFilter {
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
throws ServletException, IOException {
// 修改cookie
ModifyHttpServletRequestWrapper mParametersWrapper = new ModifyHttpServletRequestWrapper(request);
String token = request.getHeader("token");
if (token != null && !"".equals(token)) {
mParametersWrapper.putCookie("JSESSIONID", token);
}
// finish
filterChain.doFilter(mParametersWrapper, response);
}
/**
* 修改cookie信息
*/
private class ModifyHttpServletRequestWrapper extends HttpServletRequestWrapper {
private Map<String, String> mapCookies;
ModifyHttpServletRequestWrapper(HttpServletRequest request) {
super(request);
this.mapCookies = new HashMap<>();
}
void putCookie(String name, String value) {
this.mapCookies.put(name, value);
}
public Cookie[] getCookies() {
HttpServletRequest request = (HttpServletRequest) getRequest();
Cookie[] cookies = request.getCookies();
if (mapCookies == null || mapCookies.isEmpty()) {
return cookies;
}
if (cookies == null || cookies.length == 0) {
List<Cookie> cookieList = new LinkedList<>();
for (Map.Entry<String, String> entry : mapCookies.entrySet()) {
String key = entry.getKey();
if (key != null && !"".equals(key)) {
cookieList.add(new Cookie(key, entry.getValue()));
}
}
if (cookieList.isEmpty()) {
return cookies;
}
return cookieList.toArray(new Cookie[cookieList.size()]);
} else {
List<Cookie> cookieList = new ArrayList<>(Arrays.asList(cookies));
for (Map.Entry<String, String> entry : mapCookies.entrySet()) {
String key = entry.getKey();
if (key != null && !"".equals(key)) {
for (int i = 0; i < cookieList.size(); i++) {
if(cookieList.get(i).getName().equals(key)){
cookieList.remove(i);
}
}
cookieList.add(new Cookie(key, entry.getValue()));
}
}
return cookieList.toArray(new Cookie[cookieList.size()]);
}
}
}
}
2.在web.xml中注册该过滤器：
<filter>
<filter-name>ModifyParametersFilter</filter-name>
<filter-class>com.xiyinli.web.common.ModifyParametersFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>ModifyParametersFilter</filter-name>
<url-pattern>/*</url-pattern>
<!-- 直接从客户端过来的请求以及通过forward过来的请求都要经过该过滤器 -->
<dispatcher>REQUEST</dispatcher>
<dispatcher>FORWARD</dispatcher>
</filter-mapping>
如：
参考文章：
继承HttpServletRequestWrapper以实现在Filter中修改HttpServletRequest的参数