servlet 中的 java.lang.NumberFormatException 错误

Question

这是我的 jsp 表单，

<%@ page import="java.sql.*"%>
<%@ page import="java.io.*"%>


<jsp:include page="common_header.jsp" />
<center>
<form action="projects" method="post" enctype="multipart/form-data" name="productForm" id="productForm">
    <div class="row grid_12" id="add_service">
        <h2>Add Project</h2>
        <div class="grid_6">
            <label>Project Name</label>
            <div class="clear"></div>
            <input type="text" name="name" id="name" class="text_box">
        </div>
        <div class="clear"></div>

        <div class="grid_6">    
            <label>Project Short Description</label>
            <div class="clear"></div>
            <textarea name="short_description" id="short_description" class="text_area"></textarea>
        </div>
        <div class="grid_6 last">
            <label>Project Long Description</label>
            <div class="clear"></div>
            <textarea name="long_description" id="long_description" class="text_area"></textarea>
        </div>

        <div class="clear"></div>
        <div class="grid_6">
            <label>Image</label>
            <div class="clear"></div>
            <input type="file" id="file" name="file"/>
        </div>

        <div class="grid_6 last">
            <label>Link</label>
            <div class="clear"></div>
            <input type="text" name="link" id="link" class="text_box">
        </div>

        <div class="clear"></div>

        <div class="grid_6">
            <label>Status</label>
            <div class="clear"></div>
            <select id="status" name="status">
                <option value="1">In-Progress</option>
                <option value="2">Completed</option>
                <option value="3">Re-Opened</option>
                <option value="4">Just Discussed</option>
            </select>
        </div>

        <div class="grid_6 last">
            <label>Client</label>
            <div class="clear"></div>
            <input type="text" name="client" id="client" class="text_box">
        </div>

        <div class="clear"></div>
        <input type="submit" name="Submit" value="Submit">
    </div>
</form>

</center>
<jsp:include page="/common_footer.jsp" />

我正在将其提交到名为 servlet 的 projects。

代码如下：

import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;

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

import admin.project_info;

public class projects extends HttpServlet
{
    private static final long serialVersionUID = 1L;

    public void doPost(HttpServletRequest req,HttpServletResponse resp) throws ServletException,java.io.IOException
    {

        String saveFile = "";
        String contentType = req.getContentType();
        if ((contentType != null) && (contentType.indexOf("multipart/form-data") >= 0)) 
        {
            DataInputStream in = new DataInputStream(req.getInputStream());
            int formDataLength = req.getContentLength();
            byte dataBytes[] = new byte[formDataLength];
            int byteRead = 0;
            int totalBytesRead = 0;
            while (totalBytesRead < formDataLength) {
                byteRead = in.read(dataBytes, totalBytesRead, formDataLength);
                totalBytesRead += byteRead;
            }
            String file = new String(dataBytes);
            saveFile = file.substring(file.indexOf("filename=\"") + 10);
            saveFile = saveFile.substring(0, saveFile.indexOf("\n"));
            saveFile = saveFile.substring(saveFile.lastIndexOf("\\") + 1,
                    saveFile.indexOf("\""));
            int lastIndex = contentType.lastIndexOf("=");
            String boundary = contentType.substring(lastIndex + 1, contentType
                    .length());
            int pos;
            pos = file.indexOf("filename=\"");
            pos = file.indexOf("\n", pos) + 1;
            pos = file.indexOf("\n", pos) + 1;
            pos = file.indexOf("\n", pos) + 1;
            int boundaryLocation = file.indexOf(boundary, pos) - 4;
            int startPos = ((file.substring(0, pos)).getBytes()).length;
            int endPos = ((file.substring(0, boundaryLocation)).getBytes()).length;
            File ff = new File(saveFile);
            FileOutputStream fileOut = new FileOutputStream(ff);
            fileOut.write(dataBytes, startPos, (endPos - startPos));
            fileOut.flush();
            fileOut.close();

            FileInputStream fis;

            File f = new File(saveFile);

            fis = new FileInputStream(f);


            String name = req.getParameter("name");
            String short_description = req.getParameter("short_description");
            String long_description = req.getParameter("long_description");
            String link = req.getParameter("link");
            String status = req.getParameter("status");

            int astatus     =   Integer.parseInt(status);

            String client = req.getParameter("client");

            project_info p1 = new project_info(name, short_description, long_description, link, astatus, (InputStream) fis, (int) (f.length()), client); 
            p1.create();
        }

    }
}

我的 project_info 代码如下：

package admin;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

public class project_info
{
    String name, short_description, long_description, link, client;
    int id, status, file_length;
    InputStream image;

    public project_info()
    {
        name    =   null;
        short_description   =   null;
        long_description    =   null;
        link                =   null;
        id      =   0;
        status  =   0;
        image   =   null;
        file_length =   0;
    }

    public project_info(String aname, String sdescription, String ldescription, String alink, int astatus, InputStream apath,int afile_length, String aclient)
    {
        name    =   aname;
        short_description   =   sdescription;
        long_description    =   ldescription;
        link                =   alink;
        status              =   astatus;
        image               =   apath;
        file_length         =   afile_length;
        client              =   aclient;
    }



    //function for create entry in database
    public int create()
    {
        int flag = 0;
        try
        {
            Class.forName("com.mysql.jdbc.Driver");
            Connection con              = DriverManager.getConnection("jdbc:mysql://localhost/site?user=root&password=root");
            String query                = "INSERT INTO projects(name, short_description, long_description, status, link, image, client) values(?,?,?,?,?,?,?)";
            PreparedStatement statement = con.prepareStatement(query);
            statement.setString(1, name);
            statement.setString(2, short_description);
            statement.setString(3, long_description);
            statement.setInt(4, status);
            statement.setString(5, link);


            statement.setBinaryStream(6,image, file_length);

            statement.setString(7, client);
            statement.executeUpdate();
            statement.close();
            con.close();
            flag = 1;
        }
        catch (Exception e)
        {
            e.printStackTrace();
            flag = 0;
        }
        return flag;
    }
}

过去 3 天我遇到了同样的错误..！

HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

java.lang.NumberFormatException: null
    java.lang.Integer.parseInt(Unknown Source)
    java.lang.Integer.parseInt(Unknown Source)
    projects.doPost(projects.java:21)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.20 logs.
Apache Tomcat/6.0.20

我没有明白我错误的地方......！

完整的StackTrace如下

Dec 30, 2011 11:13:37 PM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.j2ee.server:Admin Website' did not find a matching property.
Dec 30, 2011 11:13:37 PM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.j2ee.server:Temp' did not find a matching property.
Dec 30, 2011 11:13:37 PM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: C:\Program Files\Java\jre6\bin;.;C:\WINDOWS\Sun\Java\bin;C:\WINDOWS\system32;C:\WINDOWS;C:/Program Files/Java/jre6/bin/client;C:/Program Files/Java/jre6/bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\Program Files\Java\jdk1.6.0_10\bin;
Dec 30, 2011 11:13:37 PM org.apache.coyote.http11.Http11Protocol init
INFO: Initializing Coyote HTTP/1.1 on http-8080
Dec 30, 2011 11:13:37 PM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 365 ms
Dec 30, 2011 11:13:37 PM org.apache.catalina.core.StandardService start
INFO: Starting service Catalina
Dec 30, 2011 11:13:37 PM org.apache.catalina.core.StandardEngine start
INFO: Starting Servlet Engine: Apache Tomcat/6.0.20
Dec 30, 2011 11:13:38 PM org.apache.coyote.http11.Http11Protocol start
INFO: Starting Coyote HTTP/1.1 on http-8080
Dec 30, 2011 11:13:38 PM org.apache.jk.common.ChannelSocket init
INFO: JK: ajp13 listening on /0.0.0.0:8009
Dec 30, 2011 11:13:38 PM org.apache.jk.server.JkMain start
INFO: Jk running ID=0 time=0/15  config=null
Dec 30, 2011 11:13:38 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 296 ms
null
null
Dec 30, 2011 11:13:58 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet projects threw exception
java.lang.NumberFormatException: null
    at java.lang.Integer.parseInt(Unknown Source)
    at java.lang.Integer.parseInt(Unknown Source)
    at projects.doPost(projects.java:73)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
    at java.lang.Thread.run(Unknown Source)

Answer 1

您应该完全重写这部分代码：

    String file = new String(dataBytes);        

    saveFile = file.substring(file.indexOf("filename=\"") + 10);
    saveFile = saveFile.substring(0, saveFile.indexOf("\n"));
    saveFile = saveFile.substring(saveFile.lastIndexOf("\\") + 1,
            saveFile.indexOf("\""));
    int lastIndex = contentType.lastIndexOf("=");
    String boundary = contentType.substring(lastIndex + 1, contentType
            .length());
    int pos;
    pos = file.indexOf("filename=\"");
    pos = file.indexOf("\n", pos) + 1;
    pos = file.indexOf("\n", pos) + 1;
    pos = file.indexOf("\n", pos) + 1;
    int boundaryLocation = file.indexOf(boundary, pos) - 4;
    int startPos = ((file.substring(0, pos)).getBytes()).length;
    int endPos = ((file.substring(0, boundaryLocation)).getBytes()).length;

有许多输入会导致此失败。考虑使用简洁的 Regex、StringUtils 和 NumberUtils 来使您的工作更轻松。这段解析代码有点味道。

祝你好运。

Answer 2

enctype="multipart/form-data" 是问题所在..！

简而言之，当我们使用 multipart/form-data 时，我们不能使用 request.getParameter()

:)

Answer 3

当您从非整数值创建整数时，会发生 NumberFormatException。您的 servlet 中的以下行导致了问题。看来“状态”值为空。确保您在“状态”字符串中获取了正确的整数值。

int astatus     =   Integer.parseInt(status);

Answer 4

我认为问题出在这一行，

int formDataLength = req.getContentLength();

或者

int astatus = Integer.parseInt(status);

这里可能是 req.getContentLength() 为 null 或 stats 为 null，当您尝试将 null 值分配给整数时，这将引发 numerformat 异常。

相反，在分配给任何变量之前检查 req.getContentLength() 是否为 null。

if(req.getContentLength() != null){
     int formDataLength = req.getContentLength();
}

if(status != null){
   int astatus = Integer.parseInt(status);
}