从Servlet内部的线程访问请求对象 [英] Accessing the request object from a thread inside a servlet

问题描述

我让此代码在servlet中运行

I have this code running in a servlet

public void doPost(HttpServletRequest request, HttpServletResponse response) {
    final HttpServletRequest requestF = request;
    Runnable runner  = new Runnable() {
       public void run() {
           String something = requestF.getParameter("anything");
           //do other things...
        }
    };
    Thread thread = new Thread(runner);
    thread.start();

但是当我尝试从请求对象中获取参数时，它将引发异常.

But it throws an Exception when i try to get the parameter from the request object.

Exception in thread "Thread-25" java.lang.NullPointerException
    at org.apache.catalina.connector.Request.parseParameters(Request.java:2560)
    at org.apache.catalina.connector.Request.getParameter(Request.java:1086)
    at org.apache.catalina.connector.RequestFacade.getParameter(RequestFacade.java:355)
    at javax.servlet.ServletRequestWrapper.getParameter(ServletRequestWrapper.java:158)
    at br.com.test.controller.ajax.MyServlet$1.run(MyServlet.java:54)
    at java.lang.Thread.run(Thread.java:619)

requestF对象不为null，我已经检查过. 有谁知道我是否可以在新的Thread中访问请求对象?

The requestF object is not null, I've checked. Does anyone know if i can access the request object inside a new Thread?

推荐答案

是的，Zaske是正确的. 您可以使用地图对象的新实例进行复制，如下所示:

Yes, Zaske is right. You may copy using a new instance of map object, like this:

final Map<String,String> mapParameters = new HashMap<String,String>();
mapParameters.putAll(request.getParameterMap());

并在运行"方法中使用mapParameters:

and use mapParameters inside your "run" method:

public void doPost(HttpServletRequest request, HttpServletResponse response) {
    final Map<String,String> mapParameters = new HashMap<String,String>();
    mapParameters.putAll(request.getParameterMap());
    Runnable runner  = new Runnable() {
       public void run() {
           String something = mapParameters.get("anything");
           //do other things...
       }
    };
    Thread thread = new Thread(runner);
    thread.start();
}

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