上传图片，空指针错误，请高手看一下
package myservlet.control;import mybean.data.*;
import java.sql.*;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class HandleUpload extends HttpServlet
{ public void init(ServletConfig config) throws ServletException
{ super.init(config);
try { Class.forName("com.mysql.jdbc.Driver");
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}
catch(Exception e){}
}
public void doPost(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException
{ HttpSession session=request.getSession(true);
Login login=(Login)session.getAttribute("login"); //获取用户登录时的Javabean
boolean ok=true;
if(login==null)
{ ok=false;
response.sendRedirect("login.jsp"); //重定向到登录页面
}
if(ok==true)
{ String logname=login.getLogname();
uploadFileMethod(request,response,logname); //接受上传文件
}
}
public void uploadFileMethod(HttpServletRequest request,HttpServletResponse response,
String logname) throws ServletException,IOException
{ UploadFile upFile=new UploadFile();
String backNews="";
try{ HttpSession session=request.getSession(true);
request.setAttribute("upFile",upFile);
String tempFileName=(String)session.getId();
File f1=new File(tempFileName);
FileOutputStream o=new FileOutputStream(f1);
InputStream in=request.getInputStream();
byte b[]=new byte[10000];
int n;
while( (n=in.read(b))!=-1)
{ o.write(b,0,n);
}
o.close();
in.close();
RandomAccessFile random=new RandomAccessFile(f1,"r");
int second=1; //读出f1的第2行，析取出上传文件的名字：
String secondLine=null;
while(second<=2)
{ secondLine=random.readLine();
second++;
}
//获取第2行中目录符号'\'最后出现的位置：
int position=secondLine.lastIndexOf('\\');
//截取文件名：
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String fileName=secondLine.substring(position+1,secondLine.length()-1);
byte cc[]=fileName.getBytes("ISO-8859-1");
fileName=new String(cc);
fileName=fileName.replaceAll(" ","");
//文件是否由字母或数字组成判断名字
String checkedStr=fileName.substring(0,fileName.indexOf("."));
boolean isLetterOrDigit=true;
for(int i=0;i<checkedStr.length();i++)
{ char c=checkedStr.charAt(i);
if(!((c<='z'&&c>='a')||(c<='Z'&&c>='A')||(c<='9'&&c>='0')))
{ isLetterOrDigit=false;
break;
}
}
if(isLetterOrDigit==false)
{ response.sendRedirect("upload.jsp"); //重定向到upload.jsp页面
}
//保存文件名是上传文件名加会员名为前缀：
String savedFileName=logname.concat(fileName);
random.seek(0);
long forthEndPosition=0; //获取第4行回车符号的位置
int forth=1;
while((n=random.readByte())!=-1&&(forth<=4))
{ if(n=='\n')
{ forthEndPosition=random.getFilePointer();
forth++;
}
}
//根据客户上传文件的名字，将该文件存入磁盘：
File dir=new File("D:/javawork/workspace/adver/WebRoot/image");
dir.mkdir();
//首先删除用户曾上传过的图像文件：
File file[]=dir.listFiles();
for(int k=0;k<file.length;k++)
{ if(file[k].getName().startsWith(logname))
file[k].delete();
}
File savingFile= new File(dir,savedFileName); //需要新保存的上传文件
RandomAccessFile random2=new RandomAccessFile(savingFile,"rw");
random.seek(random.length());
long endPosition=random.getFilePointer();
long mark=endPosition;
int j=1;
//确定出文件f1中包含客户上传的文件的内容的最后位置，即倒数第6行:
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while((mark>=0)&&(j<=6))
{ mark--;
random.seek(mark);
n=random.readByte();
if(n=='\n')
{ endPosition=random.getFilePointer();
j++;
}
}
random.seek(forthEndPosition);
long startPoint=random.getFilePointer();
while(startPoint<endPosition-1)
{ n=random.readByte();
random2.write(n);
startPoint=random.getFilePointer();
}
random2.close();
random.close();
String
uri="jdbc:mysql://localhost:3306/advertisement?useUnicode=true&characterEncoding=utf-8";
Connection con=DriverManager.getConnection(uri,"root","123456");
Statement sql=con.createStatement();
ResultSet rs=sql.executeQuery("SELECT * FROM member where logname = '"+logname+"'");
if(rs.next())
{ if(isLetterOrDigit)
{ int mm=sql.executeUpdate("UPDATE member SET pic= '"+savedFileName+"' where
logname = '"+logname+"'");
if(mm!=0)
{ backNews=fileName+"成功上传";
upFile.setFileName(fileName);
upFile.setSavedFileName(savedFileName);
upFile.setBackNews(backNews);
}
}
}
con.close();
f1.delete();
}
catch(Exception exp)
{ backNews=""+exp;
upFile.setBackNews(backNews);
}
try{ RequestDispatcher dispatcher=
request.getRequestDispatcher("showUploadMess.jsp");//转发
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dispatcher.forward(request, response);
}
catch(Exception ee){}
}
public void doGet(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException
{ doPost(request,response);
}
} --------------------编程问答-------------------- 异常呢？也贴一下 --------------------编程问答-------------------- 打个断点 debug下 --------------------编程问答-------------------- debug 最快了 --------------------编程问答-------------------- debug 会用么？ --------------------编程问答--------------------
运行没有报错，但是一上传图片，jsp页面就报错了，出现这个，java.lang.StringIndexOutOfBoundsException: String index out of range: -1
--------------------编程问答-------------------- 感觉是页面的问题，页面上有java代码的吧，在对应的页面上检查错误吧。 --------------------编程问答-------------------- 贴报错信息，贴与报错信息直接相关的代码亲，不要让我们意易做图啊。。
补充：Java , Web 开发
