使用JSF应用程序下载日志文件？ [英] Download log file using JSF application?

问题描述

在我的应用程序开发的JSF2.0 + Richfaces3.3.3 + Tomcat6.0.29。

我将日志文件保存到此位置： E：\Tomcat-6.0.29\Tomcat6.0\logs\project.log

我的tomcat（webapps）位置： E：\Tomcat-6.0.29\Tomcat 6.0\webapps

当我点击a4j：命令按钮我想下载该日志文件，而不更改内容和文件名。

以下代码在（JSF1.2）中工作。但是

转换JSF2.0后，以下代码无效。

download.jsp

 < h：form id =downloadFormbinding =＃{Download.initForm}> 
< a4j：outputPanel id =downloadOutputPanel> 
< a4j：commandButton value =下载日志
 action =＃{Download.downloadButtonAction}
 reRender =downloadOutputPanel/> < / A4J：outputpanel> 
< / h：form> 
  

Download.java

  package com.test; 
  

import java.io.File;
import javax.faces.component.html.HtmlForm;

  import javax.faces.context.ExternalContext; 
 import javax.faces.context.FacesContext; 
 import javax.servlet.http.HttpServletResponse; 
 import org.apache.log4j.Logger; 
 
 public class下载{
 
 private HtmlForm initForm; 
 
 public String downloadButtonAction（）
 {
 String fileName =logs+ File.separator +project.log; 
 System.setProperty（download.logfile，download-logfile）; 
 downloadLogFile（fileName）; 
返回null; 
} 
 
 private void downloadLogFile（String fileName）
 {
 try 
 {
 FacesContext facesContext = FacesContext.getCurrentInstance（）; 
 ExternalContext context = facesContext.getExternalContext（）; 
 HttpServletResponse response =（HttpServletResponse）context.getResponse（）; 
 fileName = fileName.replace（File.separator，/）; 
 
 response.sendRedirect（/+JSF-Richfaces-3.3.3-Demo-2+ 
 / faces / fileDownloadServlet /+ fileName）; 
} 
 catch（Exception ex）
 {
 System.out.println（下载模板时出现异常：+ ex）; 
} 
} 
 
 public HtmlForm getInitForm（）{
 return initForm; 
} 
 
 public void setInitForm（HtmlForm initForm）{
 this.initForm = initForm; 
} 
} 
  

我的 FileDownloadServlet.java / p>

  package com.test; 
 
 import javax.servlet.ServletException; 
 import java。 io.BufferedInputStream; 
 import java.io.BufferedOutputStream; 
 import java.io.Closeable; 
 import java.io.File; 
 import java.io.FileInputStream; 
 import java.io.IOException; 
 import java.net.URLDecoder; 
 import javax.servlet.ServletConfig; 
 import javax.servlet.http.HttpServlet; 
 import javax.servlet.http.HttpServletRequest; 
 import javax.servlet.http.HttpServletResponse; 
 
 public class FileDownloadServlet extends HttpServlet 
 {
 ServletConfig servletConfig; 
 
 @Override 
 public void init（ServletConfig servletConfig）
 {
 this.servletConfig = servletConfig; 
} 
 
 @Override 
 protected void doGet（HttpServletRequest request，HttpServletResponse response）
 throws IOException 
 {
 String contentType = null; 
 String filePath =; 
 String fileName =; 
 
 String requestURI = request.getRequestURI（）; 
 try 
 {
 fileName = requestURI.substring（requestURI.lastIndexOf（'/'）+ 1）; 
字符串catalinaHome =。 + File.separator +..+ File.separator; 
 
 if（System.getProperty（os.name）。contains（Windows））
 {
 catalinaHome =; 
} 
 filePath = catalinaHome + requestURI.substring（requestURI.indexOf（System.getProperty（download.logfile）），requestURI.lastIndexOf（/））; 
 filePath = filePath.replace（/，File.separator）; 
} 
 catch（异常异常）
 {
 System.out.println（解析请求URI时发生异常：+异常）; 
} 
 finally 
 {
 System.out.println（下载servlet解析后的文件路径+ filePath）; 
} 
 
 filePath = filePath + File.separator + fileName; 
 fileName = URLDecoder.decode（fileName，UTF-8）; 
文件文件= new File（filePath）; 
 
 try 
 {
 contentType = request.getSession（）。getServletContext（）。getMimeType（fileName）; 
} 
 catch（异常异常）
 {
 System.out.println（异常时获取内容类型：，异常）; 
} 
 
 if（contentType == null）
 {
 contentType =application / octet-stream; 
} 
 
 BufferedInputStream input = null; 
 BufferedOutputStream output = null; 
 try 
 {
 input = new BufferedInputStream（new FileInputStream（file））; 
 int contentLength = input.available（）; 
 
 response.reset（）; 
 response.setContentType（contentType）; 
 response.setContentLength（contentLength）; 
 response.setHeader（Content-disposition，attachment; filename = \+ 
 fileName +\）; 
 output = new BufferedOutputStream（response.getOutputStream（））; 
 
 for（int data; 
（data = input.read（））！= -1;）
 {
 output.write（data）; 
} 
 
 output.flush（）; 
} 
 catch（异常e）
 {
 System.out.println（文件下载中的异常+ e）; 
} 
 finally 
 {
 close（output）; 
关闭（输入）; 
} 
} 
 
 
 private static void close（Closeable resource）
 {
 if（resource！= null）
 {
 try 
 {
 resource.close（）; 
} 
 catch（IOException e）
 {
 System.out.println（Error，e）; 
} 
} 
} 
} 
  

web.xml

  ... 
 ... 
< servlet> ; 
< servlet-name> fileDownloadServlet< / servlet-name> 
< servlet-class> com.test.FileDownloadServlet< / servlet-class> 
< / servlet> 
< servlet-mapping> 
< servlet-name> fileDownloadServlet< / servlet-name> 
< url-pattern> / fileDownloadServlet / *< / url-pattern> 
< / servlet-mapping> 
 ... 
 ... 
  

错误是： / strong>

  HTTP状态404  -  /fileDownloadServlet/logs/project.log未找到
类型状态报告
 message /fileDownloadServlet/logs/project.log未找到
描述请求的资源（/fileDownloadServlet/logs/project.log未找到）`不可用`
 Apache Tomcat / 6.0.29 
  

同时我的地址栏显示此网址
http：// localhost ：8080 / JSF-Richfaces-3.3.3-Demo-2 / faces / fileDownloadServlet / logs / project.log

帮助我..
提前感谢。

解决方案

我宁愿推荐使用另一个servlet做压缩，并用 h：outputLink 代替。即使您设法以某种方式将文件推送到FacesServlet中，也可能不是便携式的，也可能会导致一些意想不到的问题。

1. 您将需要实施一个简单的 servlet ，它生成
   压缩的日志文件


2. 将此servlet的映射添加到您的web.xml


3. 添加 h：outputLink 与链接指向您的新servlet

In my application developed by JSF2.0 + Richfaces3.3.3 + Tomcat6.0.29.

I maintain my log file into this location : E:\Tomcat-6.0.29\Tomcat6.0\logs\project.log
My tomcat(webapps) Location : E:\Tomcat-6.0.29\Tomcat 6.0\webapps

When i click that a4j:commandbutton i want to download that log file, without change the content and filename.

The following code worked in (JSF1.2). But
After convert JSF2.0, the following code doesn't work.

download.jsp

<h:form id="downloadForm" binding="#{Download.initForm}">
        <a4j:outputPanel id="downloadOutputPanel"> 
                 <a4j:commandButton value="Download Log"
                                    action="#{Download.downloadButtonAction}"
                                    reRender="downloadOutputPanel"/>                              </a4j:outputpanel>
</h:form>

Download.java

package com.test;

import java.io.File; import javax.faces.component.html.HtmlForm;

import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.Logger;

public class Download{

private HtmlForm initForm;    

public String downloadButtonAction()
{        
    String fileName = "logs" + File.separator + "project.log";
    System.setProperty("download.logfile", "download-logfile") ;
    downloadLogFile(fileName);
    return null;
}

private void downloadLogFile(String fileName)
{
   try
   {
     FacesContext facesContext = FacesContext.getCurrentInstance();
     ExternalContext context = facesContext.getExternalContext();
     HttpServletResponse response = (HttpServletResponse) context.getResponse();
     fileName = fileName.replace(File.separator, "/");

response.sendRedirect("/" + "JSF-Richfaces-3.3.3-Demo-2" + 
                            /faces/fileDownloadServlet/" + fileName);  
}
catch (Exception ex)
{
  System.out.println("Exception occours while downloading templates: "+ ex);
 }
 }

public HtmlForm getInitForm(){        
    return initForm;
}

public void setInitForm(HtmlForm initForm){
    this.initForm = initForm;
}   
}

And my FileDownloadServlet.java class

package com.test;

import javax.servlet.ServletException;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.Closeable;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URLDecoder;
import javax.servlet.ServletConfig;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FileDownloadServlet extends HttpServlet
{
ServletConfig servletConfig;    

@Override
public void init(ServletConfig servletConfig)
{
    this.servletConfig = servletConfig;
}

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws IOException
{
    String contentType = null;
    String filePath = "";
    String fileName = "";

    String requestURI = request.getRequestURI();
    try
    {
        fileName = requestURI.substring(requestURI.lastIndexOf('/') + 1);                     
        String catalinaHome = "." + File.separator + ".." + File.separator;

        if (System.getProperty("os.name").contains("Windows"))
        {
            catalinaHome = "";
        }
        filePath = catalinaHome +  requestURI.substring(requestURI.indexOf(System.getProperty("download.logfile")), requestURI.lastIndexOf("/"));
        filePath = filePath.replace("/", File.separator);           
    }
    catch (Exception exception)
    {
        System.out.println("Exception occurred while parsing the request URI : " + exception);
    }
    finally
    {
        System.out.println("File path after parsing in download servlet : " + filePath);
    }

    filePath = filePath + File.separator + fileName;                
    fileName = URLDecoder.decode(fileName, "UTF-8");        
    File file = new File(filePath);             

    try
    {            
        contentType = request.getSession().getServletContext().getMimeType(fileName);
    }
    catch (Exception exception)
    {
        System.out.println("Exception while getting content type : ", exception);
    }

    if (contentType == null)
    {
        contentType = "application/octet-stream";
    }        

    BufferedInputStream input = null;
    BufferedOutputStream output = null;
    try
    {            
        input = new BufferedInputStream(new FileInputStream(file));
        int contentLength = input.available();           

        response.reset();
        response.setContentType(contentType);
        response.setContentLength(contentLength);
        response.setHeader("Content-disposition", "attachment; filename=\"" +
                fileName + "\"");
        output = new BufferedOutputStream(response.getOutputStream());

        for (int data;
                (data = input.read()) != -1;)
        {
            output.write(data);
        }

        output.flush();
    }
    catch (Exception e)
    {           
        System.out.println("Exception in File Download : " + e);
    }
    finally
    {           
        close(output);
        close(input);
    }
}


private static void close(Closeable resource)
{
    if (resource != null)
    {
        try
        {
            resource.close();
        }
        catch (IOException e)
        {               
            System.out.println("Error ", e);
        }
    }
}
}

web.xml

...
...
 <servlet>
    <servlet-name>fileDownloadServlet</servlet-name>
    <servlet-class>com.test.FileDownloadServlet</servlet-class>
</servlet>
 <servlet-mapping>
    <servlet-name>fileDownloadServlet</servlet-name>
    <url-pattern>/fileDownloadServlet/*</url-pattern>
</servlet-mapping>
...
...

Error is :

HTTP Status 404 - /fileDownloadServlet/logs/project.log not found
type Status report
message /fileDownloadServlet/logs/project.log not found
description The requested resource (/fileDownloadServlet/logs/project.log not found) ` is not available.`
Apache Tomcat/6.0.29

At the same time my address bar show this url http://localhost:8080/JSF-Richfaces-3.3.3-Demo-2/faces/fileDownloadServlet/logs/project.log

Help me.. Thanks in advance.

解决方案

I would rather recommend using another servlet to do the zipping and point to it with h:outputLink instead. Even if you do manage to somehow push the file through the FacesServlet it may not be portable or may cause some unexpected problems.

1. You would need to implement a simple servlet which generates a zipped log file
2. Add mapping for this servlet to your web.xml
3. Add h:outputLink with a link pointing to your new servlet

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