如何在 HttpServletRequest 中设置参数 ID,1234？

Question

我有一个包含一些参数的 HttpServletrequest。 我想将此键和值添加到该请求中。 如何用我的代码拦截它并将其添加到我的请求中？ 我创建了一个过滤器，如下所示，但实际上无法继续

public class RequestInterceptor implements Filter {        
    public RequestInterceptor() {        
    }

     
    public void destroy() {
         
    }

     
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        
        chain.doFilter(request, response);
    }

     
    public void init(FilterConfig fConfig) throws ServletException {
         
    }

我想做类似 request.setAttribute("ID", "1234") 所以这将被附加或添加到我的请求中

一般我想借助拦截器或过滤器来修改 httpServletRequest

Answer 1

我相信你可以这样做：

使用 web.xml

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class IdMutatorFilter implements Filter {

    public IdMutatorFilter() {
        // Nothing to construct
    }
    
    @Override
    public void destroy() {
        // Nothing to do here =/
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        // Your preferred method to make an object number here.
        request.setAttribute("ID", Integer.parseInt("1234"));
        // Then return they.
        chain.doFilter(request, response);
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // Nothing to do here
    }


}

您的过滤器将更改请求中的属性并通过调用chain.doFilter 方法将其转发。

在你的 web.xml 文件中，你应该在你的根目录中添加如下内容：

<filter>

    <filter-name>YourFilterName</filter-name>

    <filter-class>com.package.location.YourFilterName</filter-class>

</filter>

<filter-mapping>

    <filter-name>YourFilterName</filter-name>

    <url-pattern>/*</url-pattern>

</filter-mapping>

filter 标记注册您的过滤器，为其命名并指向实现它的类。

filter-mapping 注册 url 模式需要应用过滤器。

url-pattern 是您的过滤器将应用的模式，filter-class 是您班级的 fqn。

使用注释

使用这种方法，您不需要在web.xml 文件中注册过滤器，但您的 Servlet API 版本需要至少为 3.0。

你可以看到docs here


import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.annotation.WebInitParam;

@WebFilter(filterName = "YourFilterName",
urlPatterns = {"/*"})
public class IdMutatorFilter implements Filter {

    public IdMutatorFilter() {
        // Nothing to construct
    }

    @Override
    public void destroy() {
        // Nothing to do here =/
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        // Your preferred method to make an object number here.
        request.setAttribute("ID", Integer.parseInt("1234"));
        // Then return they.
        chain.doFilter(request, response);
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // Nothing to do here
    }


}

Answer 2

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;

/**
 * Servlet Filter implementation class RequestInterceptor
 */
@WebFilter("/RequestInterceptor")
public class RequestInterceptor implements Filter  {

    
    
    
    public RequestInterceptor() {
        // TODO Auto-generated constructor stub
    }

    /**
     * @see Filter#destroy()
     */
    public void destroy() {
        // TODO Auto-generated method stub
    }

    /**
     * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
     */
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        RequestInterceptionforIDWrappper wrapper =new RequestInterceptionforIDWrappper((HttpServletRequest) request);
        long ID=85965894;
        wrapper.setUniqueID("UID",ID);
        chain.doFilter(wrapper, response);
    }

    /**
     * @see Filter#init(FilterConfig)
     */
    public void init(FilterConfig fConfig) throws ServletException {
        // TODO Auto-generated method stub
    }



}

=============================

import java.util.HashMap;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

public class RequestInterceptionforIDWrappper extends HttpServletRequestWrapper {
    HashMap UIDkeyValue=new HashMap<>();
    public RequestInterceptionforIDWrappper(HttpServletRequest request) {
        super(request);      
    }
    
    public void setUniqueID(String UID,long ID) {
        
        UIDkeyValue.put(UID, ID);
    }
    
    @Override
    public String getParameter(String key) {
        return UIDkeyValue.toString();
    }

}

这是我尝试将键值添加到请求中的两个类，你能检查一下有什么问题吗 @ooredroxoo