Java 试图在应用程序和servlet之间连接时，URLConnection.getInputStream（）会引发FileNotFoundException

我想开发一个在Tomcat上运行的servlet文件之间进行通信的应用程序

下面是我的应用程序中的代码，它试图连接到此servlet，发送请求并获取响应

 private URLConnection getServletConnection() {
    try {
        URL servletURL = new URL("http://localhost:8080/test/servlet");
        URLConnection conn = servletURL.openConnection();

        conn.setDoInput(true);
        conn.setDoOutput(true);
        conn.setUseCaches(false);
        return conn;
    } catch (MalformedURLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return null;
}

下面是引发异常的代码：

URLConnection conn = getServletConnection();
OutputStream outputStream = conn.getOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(outputStream);
ServletRequestMessage srm = new ServletRequestMessage(2, username, password);
oos.writeObject(srm);
oos.flush();
oos.close();
InputStream inputStream = conn.getInputStream();

例外情况是：

java.io.FileNotFoundException: http://localhost:8080/test/servlet

---

有人能帮我吗？谢谢。

服务器端

public class ServletImpl extends HttpServlet implements Servlet {

    ....
    public ServletImpl() {
      super();      
    }

 public void init(ServletConfig config) throws ServletException{
    super.init(config);         


    /*
     Application scope 
     Shared between all servlets, JSP pages, and custom tags within a J2EE application 
     or within the whole container if no applications are defined.
     The programmatic interface to the application scope is the 'ServletContext' object.         
     */


    ServletContext context = config.getServletContext();
    context.setAttribute("base", config.getInitParameter("base"));
      /* where "base" is iniy param in web.xml
         <init-param>
    <param-name>base</param-name>
    <param-value>/ServlrtName/sys</param-value>
    </init-param>       


       */



....



}
    ....
protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException
{
    doPost(request, response);
}


    protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException
   {
    Enumeration<?> paramNames = request.getParameterNames();


    while(paramNames.hasMoreElements()) {

        String paramName = (String)paramNames.nextElement();

        String[] paramValues = request.getParameterValues(paramName);


         if("sub".equals(paramName)){

            paramValues = request.getParameterValues(paramName);

            if(paramValues.length > 0){

                String param = paramValues[0];
                // do something
                ....
            }               

        }           
    }
}


....
// prepear response 
    response.setContentType("text/html");

    PrintWriter out = response.getWriter();

    out.println(mMessageResponseStr);
    out.close();

客户端

public class ServletImpl extends HttpServlet implements Servlet {

    ....
    public ServletImpl() {
      super();      
    }

 public void init(ServletConfig config) throws ServletException{
    super.init(config);         


    /*
     Application scope 
     Shared between all servlets, JSP pages, and custom tags within a J2EE application 
     or within the whole container if no applications are defined.
     The programmatic interface to the application scope is the 'ServletContext' object.         
     */


    ServletContext context = config.getServletContext();
    context.setAttribute("base", config.getInitParameter("base"));
      /* where "base" is iniy param in web.xml
         <init-param>
    <param-name>base</param-name>
    <param-value>/ServlrtName/sys</param-value>
    </init-param>       


       */



....



}
    ....
protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException
{
    doPost(request, response);
}


    protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException
   {
    Enumeration<?> paramNames = request.getParameterNames();


    while(paramNames.hasMoreElements()) {

        String paramName = (String)paramNames.nextElement();

        String[] paramValues = request.getParameterValues(paramName);


         if("sub".equals(paramName)){

            paramValues = request.getParameterValues(paramName);

            if(paramValues.length > 0){

                String param = paramValues[0];
                // do something
                ....
            }               

        }           
    }
}


....
// prepear response 
    response.setContentType("text/html");

    PrintWriter out = response.getWriter();

    out.println(mMessageResponseStr);
    out.close();

我使用了

DefaultHttpClient

和

HttpPost

。我发送

sub

标签。下面是一个将数据发送到Servlet的方法：

 public boolean send(String data) {

    DefaultHttpClient httpclient = null;
    boolean success = false;

    try {           
        httpclient = new DefaultHttpClient();

        String url = "your URL";


        HttpPost httpost = new HttpPost(url);

        List <NameValuePair> nvps = new ArrayList <NameValuePair>();
        nvps.add(new BasicNameValuePair("sub", data));


        httpost.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));


        HttpResponse response = httpclient.execute(httpost);

        HttpEntity entity = response.getEntity();

        if (entity != null) {

            StatusLine statusLine = response.getStatusLine();
            int statusCode = statusLine.getStatusCode();

            if(statusCode != 200){
                mResErr.onErrorResponse(statusCode);                    
            }

            InputStream is = entity.getContent();
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);
            String line = null;
            while ( (line = br.readLine()) != null) {

                // get data from line


            }
            is.close();


        } else {
            //response is null/
        }
        success = true;

        mRes.onHttpResponse(mArr);


    } catch (Exception e) {
        mResErr.onErrorResponse(e);
        e.getStackTrace();
    }

    if (httpclient != null) {
        // resource cleanup
        httpclient.getConnectionManager().shutdown();
    }

    return success;
}   

---

服务器端

public class ServletImpl extends HttpServlet implements Servlet {

    ....
    public ServletImpl() {
      super();      
    }

 public void init(ServletConfig config) throws ServletException{
    super.init(config);         


    /*
     Application scope 
     Shared between all servlets, JSP pages, and custom tags within a J2EE application 
     or within the whole container if no applications are defined.
     The programmatic interface to the application scope is the 'ServletContext' object.         
     */


    ServletContext context = config.getServletContext();
    context.setAttribute("base", config.getInitParameter("base"));
      /* where "base" is iniy param in web.xml
         <init-param>
    <param-name>base</param-name>
    <param-value>/ServlrtName/sys</param-value>
    </init-param>       


       */



....



}
    ....
protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException
{
    doPost(request, response);
}


    protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException
   {
    Enumeration<?> paramNames = request.getParameterNames();


    while(paramNames.hasMoreElements()) {

        String paramName = (String)paramNames.nextElement();

        String[] paramValues = request.getParameterValues(paramName);


         if("sub".equals(paramName)){

            paramValues = request.getParameterValues(paramName);

            if(paramValues.length > 0){

                String param = paramValues[0];
                // do something
                ....
            }               

        }           
    }
}


....
// prepear response 
    response.setContentType("text/html");

    PrintWriter out = response.getWriter();

    out.println(mMessageResponseStr);
    out.close();

客户端

public class ServletImpl extends HttpServlet implements Servlet {

    ....
    public ServletImpl() {
      super();      
    }

 public void init(ServletConfig config) throws ServletException{
    super.init(config);         


    /*
     Application scope 
     Shared between all servlets, JSP pages, and custom tags within a J2EE application 
     or within the whole container if no applications are defined.
     The programmatic interface to the application scope is the 'ServletContext' object.         
     */


    ServletContext context = config.getServletContext();
    context.setAttribute("base", config.getInitParameter("base"));
      /* where "base" is iniy param in web.xml
         <init-param>
    <param-name>base</param-name>
    <param-value>/ServlrtName/sys</param-value>
    </init-param>       


       */



....



}
    ....
protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException
{
    doPost(request, response);
}


    protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException
   {
    Enumeration<?> paramNames = request.getParameterNames();


    while(paramNames.hasMoreElements()) {

        String paramName = (String)paramNames.nextElement();

        String[] paramValues = request.getParameterValues(paramName);


         if("sub".equals(paramName)){

            paramValues = request.getParameterValues(paramName);

            if(paramValues.length > 0){

                String param = paramValues[0];
                // do something
                ....
            }               

        }           
    }
}


....
// prepear response 
    response.setContentType("text/html");

    PrintWriter out = response.getWriter();

    out.println(mMessageResponseStr);
    out.close();

我使用了

DefaultHttpClient

和

HttpPost

。我发送

sub

标签。下面是一个将数据发送到Servlet的方法：

 public boolean send(String data) {

    DefaultHttpClient httpclient = null;
    boolean success = false;

    try {           
        httpclient = new DefaultHttpClient();

        String url = "your URL";


        HttpPost httpost = new HttpPost(url);

        List <NameValuePair> nvps = new ArrayList <NameValuePair>();
        nvps.add(new BasicNameValuePair("sub", data));


        httpost.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));


        HttpResponse response = httpclient.execute(httpost);

        HttpEntity entity = response.getEntity();

        if (entity != null) {

            StatusLine statusLine = response.getStatusLine();
            int statusCode = statusLine.getStatusCode();

            if(statusCode != 200){
                mResErr.onErrorResponse(statusCode);                    
            }

            InputStream is = entity.getContent();
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);
            String line = null;
            while ( (line = br.readLine()) != null) {

                // get data from line


            }
            is.close();


        } else {
            //response is null/
        }
        success = true;

        mRes.onHttpResponse(mArr);


    } catch (Exception e) {
        mResErr.onErrorResponse(e);
        e.getStackTrace();
    }

    if (httpclient != null) {
        // resource cleanup
        httpclient.getConnectionManager().shutdown();
    }

    return success;
}   

---

您能否指定抛出

FileNotFoundException

的确切位置？除了@Andrew之外，您是否验证了

http://localhost:8080/test/servlet

该url工作正常？@AndrewLogvinov'InputStream InputStream=conn.getInputStream（）'引发异常。有趣的是，前面的代码“OutputStream OutputStream=conn.getOutputStream（）”没有t@Fess是的，它在浏览器中工作。@缓存：Change

conn.setDoOutput（true）至
连接设置输出（假）并查看。我认为这一行正在更改请求方法。您能否指定抛出
FileNotFoundException
的确切位置？除了@Andrew之外，您是否验证了
http://localhost:8080/test/servlet
该url工作正常？@AndrewLogvinov'InputStream InputStream=conn.getInputStream（）'引发异常。有趣的是，前面的代码“OutputStream OutputStream=conn.getOutputStream（）”没有t@Fess是的，它在浏览器中工作。@缓存：Change
conn.setDoOutput（true）至
连接设置输出（假）并查看。我认为这一行正在改变请求方式。非常感谢您的帮助。但是我对你的web.xml有一个问题：你的ServletImpl.class文件在哪里？它在webapps/com/demo/servlet下吗？是的，`com.demo.servlet.ServletImpl`。从客户端获取我的示例URL：那么您需要更改server.xml文件吗？一点也不需要，您在Servlet项目中的
。/WebContent/web-INF/
下仅使用web.xml，如以下链接所示：非常感谢您的帮助。但是我对你的web.xml有一个问题：你的ServletImpl.class文件在哪里？它在webapps/com/demo/servlet下吗？是的，`com.demo.servlet.ServletImpl`。从客户端获取我的示例URL：那么您需要更改server.xml文件吗？一点也不需要，您在Servlet项目中的
。/WebContent/web-INF/
下只使用web.xml，如下链接所示：