Java Servlet下载

我写了一个用于检查http标题的servlet，但我不知道为什么当页面加载时，它会自动开始下载。Java Servlet下载

/* 
* To change this template, choose Tools | Templates 
* and open the template in the editor. 
*/ 
// =================================================== 
package HttpHeader; 

import java.io.IOException; 
import java.io.PrintWriter; 

import java.util.Enumeration; 
import java.util.zip.GZIPOutputStream; 

import javax.servlet.ServletException; 
import javax.servlet.http.HttpServlet; 

import javax.servlet.ServletConfig; 
import javax.servlet.ServletContext; 

import javax.servlet.http.HttpSession; 
import javax.servlet.http.Cookie; 

import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 

// =================================================== 
public class HeaderServlet extends HttpServlet { 

    private static final long serialVersionUID = 1234L; 

    private ServletConfig m_ServletConfig; 
    private ServletContext m_ServletContext; 

    private boolean m_HasCompress; 

    private int m_ContentLength; 

    private Cookie[] m_Cookies; 
    private String m_AuthenticationType; 
    private String m_RemoteUser; 
    private String m_ContentType; 

    private String m_Method; 
    private String m_RequestURI; 
    private String m_Date; 
    private String m_QueryStr; 
    private String m_Protocol; 

    private Enumeration<String> m_HeaderNames; 

    private HttpSession m_Session; 
    //====================================================== 

    protected void processRequest(HttpServletRequest request, HttpServletResponse response) 
    throws ServletException, IOException { 

     response.setContentType("text/html;charset=UTF-8"); 
     PrintWriter out = response.getWriter(); 

     try { 
      /* TODO output your page here 
      out.println("<html>"); 
      out.println("<head>"); 
      out.println("<title>Servlet HeaderServlet</title>"); 
      out.println("</head>"); 
      out.println("<body>"); 
      out.println("<h1>Servlet HeaderServlet at " + request.getContextPath() + "</h1>"); 
      out.println("</body>"); 
      out.println("</html>"); 
      */ 
     } finally { 
      out.close(); 
     } 
    } 

    @Override 
    protected void doHead(HttpServletRequest request, HttpServletResponse response) 
        throws ServletException, IOException { 


     String encoding = request.getHeader("Accept-Header"); 
     if(encoding != null && encoding.indexOf("gzip") != -1) 
     { 
      m_HasCompress = true; 
     } 
     else 
     { 
      m_HasCompress = false; 
     } 

     m_ContentLength = request.getContentLength(); 

     m_Cookies = request.getCookies(); 

     // Basic, Form, Client certification authentication, 
     // digest authentication 
     // Same with CGI AUTH_TYPE 
     m_AuthenticationType = request.getAuthType(); 

     m_RemoteUser = request.getRemoteUser(); 

     m_ContentType = request.getContentType(); 

     // Return get, post, delete, put 
     // Same with CGI REQUEST_METHOD 
     m_Method = request.getMethod(); 

     m_RequestURI = request.getRequestURI(); 

     // Same with CGI QUERY_STRING 
     m_QueryStr = request.getQueryString(); 

     // Same with CGI SERVER_PROTOCOL 
     m_Protocol = request.getProtocol(); 

     m_HeaderNames = request.getHeaderNames(); 

     m_Session = request.getSession(true); 

     /* Accept 
     * = MIME type 
     * 
     * Accept-Charset 
     * = UTF-8 
     * 
     * Accpet-Encoding 
     * = Compression - gzip 
     * 
     * Accept-Language 
     * = us 
     * 
     * Authorization 
     * = Login 
     * 
     * Content-Length 
     * = Post request 
     * 
     * Cookie 
     * Host 
     * 
     * If-Modified-since 
     * = Implements getLastModified 
     * = Get request 
     * 
     * If-Unmodified-since 
     * = Post request 
     * 
     * Referer 
     * = Request origin 
     * 
     * User Agent 
     * = Mozilla 
     */ 
    } 

    @Override 
    protected void doGet(HttpServletRequest request, HttpServletResponse response) 
    throws ServletException, IOException { 

     PrintWriter out = null; 
     try { 

      doHead(request, response); 

      response.setContentType("/text/html;charset=UTF-8"); 
      response.setBufferSize(8192); 

      if(m_HasCompress) 
      { 
       out = new PrintWriter(new GZIPOutputStream(response.getOutputStream())); 
       response.setHeader("Content-Encoding", "gzip"); 
      } 
      else 
      { 
       out = response.getWriter(); 
      } 

      if (out != null) { 

       String docType = "<!DOCTYPE HTML PUBLIC " 
         + "\"-//W3C//DTD HTML 4.01 " 
         + "Transitional//EN\">\n\n"; 

       out.println(docType 
         + "<html> <head> " 
         + " <title> Http Request Header<title>" 
         + "Requst Method : " + m_Method + "<p></p>" 
         + "Request URI : " + m_RequestURI + "<p></p>" 
         + "Request Protocol : " + m_Protocol + "<p></p><p></p>" 
         + "<table BORDER=1 ALIGN =\"CENTER\">" 
         + "<TH>Header Name <TH>Header Value"); 

       String headerName = new String(); 
       String headerValue = new String(); 
       while(m_HeaderNames.hasMoreElements()) 
       { 
        headerName = m_HeaderNames.nextElement(); 
        if(headerName != null) 
        { 
        headerValue = request.getHeader(headerName); 

        out.println("<TR><TD>" + headerName); 
        out.println(" <TD>" + headerValue); 
        } 
       } 

       out.println("</table>" + "<p></p>" 
         + "</head></html>"); 
       out.close(); 

      } 

     } 
     finally { 

      out.close(); 
     } 



     /* 
     * HTTP 1.1 request headers 
     * Request Header set by browser 
     * Get Reqeust - Query Data same line 
     * POst Request - Query Data next line 
     * 
     */ 

     //processRequest(request, response); 
    } 

    @Override 
    protected void doPost(HttpServletRequest request, HttpServletResponse response) 
    throws ServletException, IOException { 
//  processRequest(request, response); 
    } 

    @Override 
    public String getServletInfo() { 
     return "Short description"; 
    }// </editor-fold> 

} 
// =================================================== 



<%@page contentType="text/html" pageEncoding="UTF-8"%> 

<%@taglib prefix="f" uri="http://java.sun.com/jsf/core"%> 
<%@taglib prefix="h" uri="http://java.sun.com/jsf/html"%> 

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
    "http://www.w3.org/TR/html4/loose.dtd"> 

<%-- 
    This file is an entry point for JavaServer Faces application. 
--%> 
<f:view> 
    <html> 
     <head> 
      <meta http-equiv="REFRESH" content="0; url=HeaderServlet; charset=UTF-8"/> 
      <title>JSP Page</title> 
     </head> 
     <body> 
      <h1><h:outputText value="JavaServer Faces"/></h1> 
     </body> 
    </html> 
</f:view> 

<?xml version="1.0" encoding="UTF-8"?> 
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> 
    <context-param> 
     <param-name>javax.faces.PROJECT_STAGE</param-name> 
     <param-value>Development</param-value> 
    </context-param> 
    <servlet> 
     <servlet-name>Faces Servlet</servlet-name> 
     <servlet-class>javax.faces.webapp.FacesServlet</servlet-class> 
     <load-on-startup>1</load-on-startup> 
    </servlet> 
    <servlet> 
     <servlet-name>HeaderServlet</servlet-name> 
     <servlet-class>HttpHeader.HeaderServlet</servlet-class> 
    </servlet> 
    <servlet-mapping> 
     <servlet-name>Faces Servlet</servlet-name> 
     <url-pattern>/faces/*</url-pattern> 
    </servlet-mapping> 
    <servlet-mapping> 
     <servlet-name>HeaderServlet</servlet-name> 
     <url-pattern>/HeaderServlet</url-pattern> 
    </servlet-mapping> 
    <session-config> 
     <session-timeout> 
      30 
     </session-timeout> 
    </session-config> 
    <welcome-file-list> 
     <welcome-file>faces/welcomeJSF.jsp</welcome-file> 
    </welcome-file-list> 
</web-app>

加载的URL是http://localhost:8080/HttpHeader/。我尝试调试，但从未发现任何奇怪的东西。请帮帮我。

谢谢。

来源

2011-04-03 peterwkc

变化

response.setContentType("text/html;charset=UTF-8"); 
//instead of: 
//response.setContentType("/text/html;charset=UTF-8");

小书于：记住的servlet的无状态特性 - servlet是单身。这意味着，就你的情况而言，如果2个客户调用你的servlet，结果将是不可预测的。这是因为你有许多字段应该是每个客户端特定的，实际上这些字段可能会被错误地修改，因为同时调用Servlet：对于一个客户端，它将会工作，对于多个servlet可能被破坏 - 如果您有多个客户，请更改您的实施。

来源

2011-04-03 10:25:24 smas

其实我已经找到了正确的语句是text/html而不是/ text/html的答案。好。我了解这里的并发问题，并感谢您的建议。让我想想如何通过向代码的方法或代码块添加synchronized关键字来解决此问题。哪一个更好或者你有更好的建议？ – peterwkc 2011-04-04 03:27:36

我永远不知道这个servlet是单身人士。我想我应该根据他们的用户ID或某种类型的会话ID来绑定特定的用户数据，否则数据将在第二次请求时被覆盖。谢谢。任何参考？ – peterwkc 2011-04-04 04:04:22

oRemove从这些代码行（或评论他们）

response.setContentType("/text/html;charset=UTF-8"); 
response.setBufferSize(8192);

response.setHeader("Content-Encoding", "gzip");

这将停止获取下载

页面，你会得到一个出来把包含的细节要求..

希望这有助于...

来源

2011-04-03 09:36:22

Java Servlet下载

回答

相关问题