本质上来讲，request请求当中的参数是无法更改的，也不能添加或者删除。
但在后台程序中，一般对request的参数的操作，都是通过request的getParameter、getParameterNames、getParameterValues等方法执行的；所以我们要是能重写这些方法，就从侧面改变了request的请求参数。恰好，servlet就提供了一个HttpServletRequestWrapper类来供大家去继承（该类是HttpServletRequest的封装类），重写request相关方法。
这样可以修改比如shiro框架中的JSESSIONID，使单页H5中调用接口时只需要在头部添加在别处登录之后拿到的jsessionid的值，就能保证是登录状态。
具体服务端实现如下：
package webapp.conf; import org.apache.tomcat.util.http.MimeHeaders;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.filter.OncePerRequestFilter; import javax.servlet.*;
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.lang.reflect.Field;
import java.util.*; /**
* 拦截器配置
*/
@Configuration
public class FilterConfig { @Bean
public FilterRegistrationBean modifyParametersFilter() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(new ModifyParametersFilter());
registration.addUrlPatterns("/*"); // 拦截路径
registration.setName("modifyParametersFilter"); // 拦截器名称
registration.setOrder(1); // 顺序
return registration;
} /**
* 自定义拦截器
*/
class ModifyParametersFilter extends OncePerRequestFilter {
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
// 修改请求头
Map<String, String> map = new HashMap<>();
modifyHeaders(map, request); // 修改cookie
ModifyHttpServletRequestWrapper requestWrapper = new ModifyHttpServletRequestWrapper(request);
String token = request.getHeader("token");
if (token != null && !"".equals(token)) {
requestWrapper.putCookie("SHIROSESSIONID", token);
} // finish
filterChain.doFilter(requestWrapper, response);
}
} /**
* 修改请求头信息
* @param headerses
* @param request
*/
private void modifyHeaders(Map<String, String> headerses, HttpServletRequest request) {
if (headerses == null || headerses.isEmpty()) {
return;
}
Class<? extends HttpServletRequest> requestClass = request.getClass();
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);
Field headers = o1.getClass().getDeclaredField("headers");
headers.setAccessible(true);
MimeHeaders o2 = (MimeHeaders)headers.get(o1);
for (Map.Entry<String, String> entry : headerses.entrySet()) {
o2.removeHeader(entry.getKey());
o2.addValue(entry.getKey()).setString(entry.getValue());
}
} catch (Exception e) {
e.printStackTrace();
}
} /**
* 修改cookie信息
*/
class ModifyHttpServletRequestWrapper extends HttpServletRequestWrapper {
private Map<String, String> mapCookies;
ModifyHttpServletRequestWrapper(HttpServletRequest request) {
super(request);
this.mapCookies = new HashMap<>();
}
public 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()]);
}
}
} }