通用FileUpload（阿帕奇）

我在这里获得空指针异常：通用FileUpload（阿帕奇）

List fileItems = upload.parseRequest(req);

那天正好，如果文件中的行数是2000年的更大的约，因为我可以上传行的文件1000以上。有人请帮助我。表格如下。

<form name="fos_picks" id="fos_picks" action="<%=path%>/fos_upld" method="post" enctype="multipart/form-data" > 

<br/><br/><br/><br/> 
<p align="center"> 
    <input type="file" name="file" size="50" /><br/> 
    <br/> 
    <input type="submit" class="buttons" value="Upload File" /> 
    </p> 
</form>

上传控制器代码...

package file_proc; 
import DBConn.DBConn; 
import java.io.BufferedReader; 
import java.io.File; 
import java.io.FileReader; 
import java.sql.PreparedStatement; 
import java.util.Iterator; 
import java.util.List; 
import javax.servlet.RequestDispatcher; 
import javax.servlet.ServletContext; 
import javax.servlet.ServletException; 
import javax.servlet.annotation.WebServlet; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import org.apache.commons.fileupload.FileItem; 
import org.apache.commons.fileupload.disk.DiskFileItemFactory; 
import org.apache.commons.fileupload.servlet.ServletFileUpload; 


@WebServlet(name="file_upld", urlPatterns = {"/file_upld"}) 

public class file_upld extends HttpServlet { 

    private boolean isMultipart; 
    private String filePath; 
    private int maxFileSize = 50 * 1024; 
    private int maxMemSize = 10 * 1024; 
    private File file ; 

/* public void init(){ 
     // Get the file location where it would be stored. 
     filePath = 
      getServletContext().getInitParameter("file-upload"); 
    }*/ 
    @Override 
    public void doPost(HttpServletRequest req, HttpServletResponse res)throws ServletException, java.io.IOException { 
     // Check that we have a file upload request 
     java.io.PrintWriter out = res.getWriter(); 
    // out.println("entered"); 
     isMultipart = ServletFileUpload.isMultipartContent(req); 

     res.setContentType("text/html"); 

     if(!isMultipart){ 
     out.println("!multipart"); 
     System.out.println("here"); 
     return; 
     } 
     DiskFileItemFactory factory = new DiskFileItemFactory(); 
     // maximum size that will be stored in memory 
     factory.setSizeThreshold(maxMemSize); 
     // Location to save data that is larger than maxMemSize. 
     factory.setRepository(new File("c:/temp")); 
     // Create a new file upload handler 
     ServletFileUpload upload = new ServletFileUpload(factory); 
     // maximum file size to be uploaded. 
     upload.setSizeMax(maxFileSize); 
ServletContext servletContext = getServletContext(); 
    String path = servletContext.getRealPath("/"); 
    BufferedReader br=null; 
    String fileName=""; 
    DBConn db = new DBConn(); 

     try{ 
     // Parse the request to get file items. 
      System.out.println("here1"+req); 
     List fileItems = upload.parseRequest(req); 

     // Process the uploaded file items 
     Iterator i = fileItems.iterator(); 

/*  out.println("<html>"); 
     out.println("<head>"); 
     out.println("<title>Upload</title>"); 
     out.println("</head>"); 
     out.println("<body>");*/ 
     while (i.hasNext()) 
     { 
     FileItem fi = (FileItem)i.next(); 
     if (!fi.isFormField()) 
     { 
      // Get the uploaded file parameters 
      String fieldName = fi.getFieldName(); 
      fileName = fi.getName(); 
      String contentType = fi.getContentType(); 
      boolean isInMemory = fi.isInMemory(); 
      long sizeInBytes = fi.getSize(); 
      // Write the file 
      if(fileName.lastIndexOf("\\") >= 0){ 
       file = new File("c:/Temp/" + 
       fileName.substring(fileName.lastIndexOf("\\"))) ; 
      }else{ 
       file = new File("c:/Temp/"+ 
       fileName.substring(fileName.lastIndexOf("\\")+1)) ; 
      } 
      if(!file.exists()) 
      { 
       File fold=new File(file.getParent()); 
       fold.mkdirs(); 
      } 
      fi.write(file) ; 
      System.out.println("Uploaded Filename: " + fileName + "<br>"); 
     } 
     } 
     }catch(Exception ce) 
     { 
      out.println("<font size='30' color='red'>Error Code 016</font>"); 
     //out.println("Exception1: "+ce); 
     } 
//read uploaded file and insert into table******************************************** 

    //  String newline = System.getProperty("line.separator"); 
// File file = new File(path+"//"+fileName); 
      // file.createNewFile(); 
try{ 

    if(file.isFile()) 
    { 
     br = new BufferedReader(new FileReader(file)); 
    String str=""; 
    String temp[]=null; 


     file.canWrite(); 
     file.canRead(); 
     file.setWritable(true); 

     db.conn.setAutoCommit(false); 
     while((str=br.readLine())!=null) 
        { 
         temp=str.split(" "); 

       //  PreparedStatement ps = db.conn.prepareStatement("INSERT INTO file_proc VALUES(?,?,?,?,?,?,?,?,?,STR_TO_DATE(?,'%m/%d/%Y'))"); 
         PreparedStatement ps = db.conn.prepareStatement("INSERT INTO file_proc(run_date,zone,location,bank,file_type,num_rec,ex_sett_date,ex_stat_date) " 
                 + "VALUES(STR_TO_DATE(?,'%m/%d/%Y'),?,?,?,?,?,STR_TO_DATE(?,'%m/%d/%Y'),STR_TO_DATE(?,'%m/%d/%Y'))"); 
         ps.setString(1,temp[0]); 
         ps.setString(2,temp[1]); 
         ps.setString(3,temp[2]); 
         ps.setString(4,temp[3]); 
         ps.setString(5,temp[4]); 
         ps.setInt(6,Integer.parseInt(temp[5])); 
         ps.setString(7,temp[6]); 
         ps.setString(8,temp[7]); 
         ps.executeUpdate(); 
         ps.close();  

        } 
        db.conn.commit(); 
        db.conn.setAutoCommit(true); 
        db.conn.close(); 
        br.close(); 
     file.delete(); 

     // RequestDispatcher rd = req.getRequestDispatcher("./status/status.jsp"); 
     // rd.forward(req, res); 
      out.print("success"); 
    //  out.println("</html>"); 
    } 
    else 
    { 
     out.println(file+" is not a file"); 
    }   

    }catch(Exception ex) { 
    out.println("file name= "+fileName); 
     // out.println("DBEX= "+ex); 
     out.println("<font size='30' color='red'>Error Code 017 - Recommended date format = m/d/yyyy.</font>"); 
     out.println("<font size='30' color='red'>Check the column order</font>"+ex);  
     //file.delete(); 
    // RequestDispatcher rd = req.getRequestDispatcher("./status/error.jsp"); 
// rd.forward(req, res); 
    }finally{ 
        try{ 
         db.conn.close(); 
         br.close(); 
        }catch(Exception e){} 
       } 
    } 
    @Override 
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, java.io.IOException { 

     doPost(request, response); 
    } 
}

** * *这里是形式* ** * **

<form name="file_proc" id="file_proc" method = "post" action="../file_upld" enctype="multipart/form-data"> 
    <br/><br/><br/><br/> 
    <p align="center"> 
<input type="file" id="file" name="file" size="50" /><br/> 
<br/> 
<input type="submit" class="buttons" value="Upload File" />br/><br/><br/> 
    </p> 
</form>

上传控制器代码...

package file_proc; 
import DBConn.DBConn; 
import java.io.BufferedReader; 
import java.io.File; 
import java.io.FileReader; 
import java.sql.PreparedStatement; 
import java.util.Iterator; 
import java.util.List; 
import javax.servlet.RequestDispatcher; 
import javax.servlet.ServletContext; 
import javax.servlet.ServletException; 
import javax.servlet.annotation.WebServlet; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import org.apache.commons.fileupload.FileItem; 
import org.apache.commons.fileupload.disk.DiskFileItemFactory; 
import org.apache.commons.fileupload.servlet.ServletFileUpload; 


@WebServlet(name="file_upld", urlPatterns = {"/file_upld"}) 

public class file_upld extends HttpServlet { 

    private boolean isMultipart; 
    private String filePath; 
    private int maxFileSize = 50 * 1024; 
    private int maxMemSize = 10 * 1024; 
    private File file ; 

/* public void init(){ 
     // Get the file location where it would be stored. 
     filePath = 
      getServletContext().getInitParameter("file-upload"); 
    }*/ 
    @Override 
    public void doPost(HttpServletRequest req, HttpServletResponse res)throws ServletException, java.io.IOException { 
     // Check that we have a file upload request 
     java.io.PrintWriter out = res.getWriter(); 
    // out.println("entered"); 
     isMultipart = ServletFileUpload.isMultipartContent(req); 

     res.setContentType("text/html"); 

     if(!isMultipart){ 
     out.println("!multipart"); 
     System.out.println("here"); 
     return; 
     } 
     DiskFileItemFactory factory = new DiskFileItemFactory(); 
     // maximum size that will be stored in memory 
     factory.setSizeThreshold(maxMemSize); 
     // Location to save data that is larger than maxMemSize. 
     factory.setRepository(new File("c:/temp")); 
     // Create a new file upload handler 
     ServletFileUpload upload = new ServletFileUpload(factory); 
     // maximum file size to be uploaded. 
     upload.setSizeMax(maxFileSize); 
ServletContext servletContext = getServletContext(); 
    String path = servletContext.getRealPath("/"); 
    BufferedReader br=null; 
    String fileName=""; 
    DBConn db = new DBConn(); 

     try{ 
     // Parse the request to get file items. 
      System.out.println("here1"+req); 
     List fileItems = upload.parseRequest(req); 

     // Process the uploaded file items 
     Iterator i = fileItems.iterator(); 

/*  out.println("<html>"); 
     out.println("<head>"); 
     out.println("<title>Upload</title>"); 
     out.println("</head>"); 
     out.println("<body>");*/ 
     while (i.hasNext()) 
     { 
     FileItem fi = (FileItem)i.next(); 
     if (!fi.isFormField()) 
     { 
      // Get the uploaded file parameters 
      String fieldName = fi.getFieldName(); 
      fileName = fi.getName(); 
      String contentType = fi.getContentType(); 
      boolean isInMemory = fi.isInMemory(); 
      long sizeInBytes = fi.getSize(); 
      // Write the file 
      if(fileName.lastIndexOf("\\") >= 0){ 
       file = new File("c:/Temp/" + 
       fileName.substring(fileName.lastIndexOf("\\"))) ; 
      }else{ 
       file = new File("c:/Temp/"+ 
       fileName.substring(fileName.lastIndexOf("\\")+1)) ; 
      } 
      if(!file.exists()) 
      { 
       File fold=new File(file.getParent()); 
       fold.mkdirs(); 
      } 
      fi.write(file) ; 
      System.out.println("Uploaded Filename: " + fileName + "<br>"); 
     } 
     } 
     }catch(Exception ce) 
     { 
      out.println("<font size='30' color='red'>Error Code 016</font>"); 
     //out.println("Exception1: "+ce); 
     } 
//read uploaded file and insert into table******************************************** 

    //  String newline = System.getProperty("line.separator"); 
// File file = new File(path+"//"+fileName); 
      // file.createNewFile(); 
try{ 

    if(file.isFile()) 
    { 
     br = new BufferedReader(new FileReader(file)); 
    String str=""; 
    String temp[]=null; 


     file.canWrite(); 
     file.canRead(); 
     file.setWritable(true); 

     db.conn.setAutoCommit(false); 
     while((str=br.readLine())!=null) 
        { 
         temp=str.split(" "); 

       //  PreparedStatement ps = db.conn.prepareStatement("INSERT INTO file_proc VALUES(?,?,?,?,?,?,?,?,?,STR_TO_DATE(?,'%m/%d/%Y'))"); 
         PreparedStatement ps = db.conn.prepareStatement("INSERT INTO file_proc(run_date,zone,location,bank,file_type,num_rec,ex_sett_date,ex_stat_date) " 
                 + "VALUES(STR_TO_DATE(?,'%m/%d/%Y'),?,?,?,?,?,STR_TO_DATE(?,'%m/%d/%Y'),STR_TO_DATE(?,'%m/%d/%Y'))"); 
         ps.setString(1,temp[0]); 
         ps.setString(2,temp[1]); 
         ps.setString(3,temp[2]); 
         ps.setString(4,temp[3]); 
         ps.setString(5,temp[4]); 
         ps.setInt(6,Integer.parseInt(temp[5])); 
         ps.setString(7,temp[6]); 
         ps.setString(8,temp[7]); 
         ps.executeUpdate(); 
         ps.close();  

        } 
        db.conn.commit(); 
        db.conn.setAutoCommit(true); 
        db.conn.close(); 
        br.close(); 
     file.delete(); 

     // RequestDispatcher rd = req.getRequestDispatcher("./status/status.jsp"); 
     // rd.forward(req, res); 
      out.print("success"); 
    //  out.println("</html>"); 
    } 
    else 
    { 
     out.println(file+" is not a file"); 
    }   

    }catch(Exception ex) { 
    out.println("file name= "+fileName); 
     // out.println("DBEX= "+ex); 
     out.println("<font size='30' color='red'>Error Code 017 - Recommended date format = m/d/yyyy.</font>"); 
     out.println("<font size='30' color='red'>Check the column order</font>"+ex);  
     //file.delete(); 
    // RequestDispatcher rd = req.getRequestDispatcher("./status/error.jsp"); 
// rd.forward(req, res); 
    }finally{ 
        try{ 
         db.conn.close(); 
         br.close(); 
        }catch(Exception e){} 
       } 
    } 
    @Override 
    public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, java.io.IOException { 

     doPost(request, response); 
    } 
}

** * *这里是形式* ** * **

<form name="file_proc" id="file_proc" method = "post" action="../file_upld" enctype="multipart/form-data"> 
    <br/><br/><br/><br/> 
    <p align="center"> 
<input type="file" id="file" name="file" size="50" /><br/> 
<br/> 
<input type="submit" class="buttons" value="Upload File" />br/><br/><br/> 
    </p> 
</form>

这里是th e log4j的东西，它显示了filter.java的错误，我没有在当前的servlet中使用它。

[错误] 29:05（file_upld.java:doPost:172）failed！

显示java.lang.NullPointerException处 javax.servlet.http.HttpServlet.service（HttpServlet.java:641） file_proc.file_upld.doPost（file_upld.java:120）在 javax.servlet.http.HttpServlet 。服务（HttpServlet.java:722）在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:305）在 org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:210） at filter.filter.doFilter（filter.java:16）at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:243） at org.ap ache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:210）在 org.apache.catalina.core.StandardWrapperValve.invoke（StandardWrapperValve.java:225）在 org.apache.catalina.core.StandardContextValve。调用（StandardContextValve.java:169）在 org.apache.catalina.authenticator.AuthenticatorBase.invoke（AuthenticatorBase.java:472）在 org.apache.catalina.core.StandardHostValve.invoke（StandardHostValve.java:168）在 org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:98）在 org.apache.catalina.valves.AccessLogValve.invoke（AccessLogValve.java:927）在 org.apache.catalina.core.StandardEngineValve.invoke（StandardEngineValve。的java：118）在 org.apache.catalina.connector.CoyoteAdapter.service（CoyoteAdapter.java:407）在 org.apache.coyote.http11.AbstractHttp11Processor.process（AbstractHttp11Processor.java:999）在有机.apache.coyote.AbstractProtocol $ AbstractConnectionHandler.process（AbstractProtocol.java:565）在 org.apache.tomcat.util.net.JIoEndpoint $ SocketProcessor.run（JIoEndpoint.java:307）在的java.util.concurrent .ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1110） at java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:603） at java.lang.Thread.run（Thread.java:722）

这里使用filter.javapackage过滤器;

import java.io.IOException; 
import javax.servlet.*; 
import javax.servlet.http.HttpServletResponse; 

public class filter implements Filter{ 

    private FilterConfig config=null; 
    @Override 
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException 
{ 
    HttpServletResponse hsr = (HttpServletResponse) res; 
    hsr.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1. 
    hsr.setHeader("Pragma", "no-cache"); // HTTP 1.0. 
    hsr.setDateHeader("Expires", 0); // Proxies. 
    chain.doFilter(req, res); 
} 
    @Override 
    public void destroy() { } 
    @Override 
    public void init(FilterConfig config) { 
    this.config = config; 
    } 
}

来源

2012-10-10 user1544102

是否使用Spring框架？请分享您的上传控制器代码。 –

不，我没有使用任何框架.. – user1544102

我不能上传8小时，因为我有不到10名声誉:( – user1544102

您的具体问题是由异常处理和控制器的紧耦合视图造成的。

从您的代码滤除噪声后，它会大致是：

File file = null; 

try { 
    // ... 
    file = new File(...); 
    // ... 
} catch (Exception e) { 
    out.println("..."); 
} 

try { 
    if (file.isFile()) 
     // ... 
    } else { 
     // ... 
    } 
} catch (Exception e) { 
    out.println("..."); 
}

的NullPointerException在与if (file.isFile())块行被抛出。这意味着第一个try区块引发异常，因此将file作为null。

的问题的原因是双重的：

第一try块没有从servlet方法返回上异常，但不正确地继续代码流。
如果file不是null，则第二个try块未事先检查。

然而，您的具体问题要大得多。您完全吞咽异常并打印不相关的HTML代码，而不是通过抛出它们和/或记录异常。

更换你的catch块如下：

} catch (Exception e) { 
    throw new ServletException(e); 
}

默认情况下，这样的异常将被记录并显示在其盛开，完整的堆栈跟踪，在一个HTTP 500错误页面。堆栈跟踪为您提供丰富的信息来了解问题并修复问题。

无关到具体的问题，也有在代码中的许多其他概念和设计错误，但他们至今没有直接相关的具体问题。不过，我会建议暂停并浏览一些理智的Servlet书籍/教程/资源。这段代码似乎只是基于谷歌中的代码片拼凑起来的，而不是写得很好。第一步是理解的servlet是如何工作的：How do servlets work? Instantiation, sessions, shared variables and multithreading

来源

2012-10-11 19:53:42 BalusC

非常感谢你们，我会努力解决我的错误，并且我正在通过给定的链接。 :) – user1544102

K. Guyz终于我潜入异常处理并学会了它。我得到这个异常..apache.commons.fileupload.FileUploadBase $ SizeLimitExceededException：该请求被拒绝，因为它的大小（220582）超过配置的最大值（51200）现在求解..增加的文件大小。谢谢 – user1544102

不客气。你不需要尖叫顺便说一句。 – BalusC

通用FileUpload（阿帕奇）

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