关于文件下载

Action代码

package org.rm.action;

import java.io.FileInputStream;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.List;
import javax.servlet.http.HttpServletResponse;
import org.rm.model.FileUpload;
import org.rm.service.FileUploadService;
import com.opensymphony.webwork.ServletActionContext;
import com.opensymphony.xwork.ActionSupport;
import com.opensymphony.xwork.ModelDriven;
/**
 * @author 作者 zhenggang E-mail:
 * @version 创建时间：2007-5-17 下午05:52:59
 * 类说明
 */
public class FileDownloadAction extends ActionSupport implements ModelDriven{

    private FileUploadService fileuploadService;
    private FileUpload fileinfo = new FileUpload();
    private List listfile;

   // private String filepath;

    public String execute() throws Exception {
        //创建、获得当前的Response 对象
        HttpServletResponse response = ServletActionContext.getResponse();
        //把页面传来的文件名、文件路径做为方法“fileDownload”的参数
        fileDownload(response, fileinfo.getFilepath(), fileinfo.getFileFilename());

        return SUCCESS;
    }

    public String fileDownload(HttpServletResponse response,String filepath, String filename) throws Exception{
        response.reset();
        response.setContentType("application/x-download");// 设置为下载application/x-download
        String filenamedownload = filepath;
        String filenamedisplay = filename;
        filenamedisplay = URLEncoder.encode(filenamedisplay, "UTF-8");
        response.addHeader("Content-Disposition", "attachment;filename="+ filenamedisplay);

//      String aa=new String();
//      aa.substring(aa.lastIndexOf("."), aa.length()).equals(".jpg");

        OutputStream output = null; //输出流写文件
        FileInputStream fis = null; //文件输入流读文件
        try {
            output = response.getOutputStream();
            fis = new FileInputStream(filenamedownload+"/"+filename);
            byte[] b = new byte[1024]; //字节数组
            int i = 0;
            while ((i = fis.read(b)) > 0) {
                output.write(b, 0, i);
            }
            output.flush(); //清空缓冲区
        } catch (Exception e) {
            e.printStackTrace();
        } finally { //关闭流
            if (fis != null) {
                fis.close();
                fis = null;
            }
            if (output != null) {
                output.close();
                output = null;
            }
        }
        return null;
    }
    public String input(){
        listfile = fileuploadService.getAllFileInfo();

        for(int i=0; i
            FileUpload f = (FileUpload)listfile.get(i);
            System.out.println(f.getFileFilename()+"\t"+f.getFilepath());
        }

        return INPUT;

    }

    public Object getModel() {

        return fileinfo;
    }
    public void setFileuploadService(FileUploadService fileuploadService) {
        this.fileuploadService = fileuploadService;
    }
    public List getListfile() {
        return listfile;
    }

}

页面文件：fileshow.ftl

显示文件
<#list listfile as l>
    <table>
        <tr>
            <td>
        <a href="filedownload.do?model.filepath=${l.filepath}&model.fileFilename=${l.fileFilename}">${l.fileFilename}a>
            td>
            <td>
                <a href="deletefile.do?model.id=${l.id}">删除a>
            td>
        tr>
        <#if l.fielContentType="1">
        <tr>
            <td ><img width="200" height="150" id="3" src="${l.filepath}${l.fileFilename}" border=0>td>
        tr>
        #if>

    table>
#list>
<p><a href="fileupload!input.do">继续添加a>

控制台信息：

17:11:15.156 ERROR! [SocketListener0-1] com.opensymphony.webwork.dispatcher.DispatcherUtils.serviceAction(DispatcherUtils.java:237) >17> Could not execute action
java.lang.StringIndexOutOfBoundsException: String index out of range: -1
    at java.lang.String.substring(String.java:1762)
    at org.rm.action.FileDownloadAction.fileDownload(FileDownloadAction.java:54)
    at org.rm.action.FileDownloadAction.execute(FileDownloadAction.java:40)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:585)
    at com.opensymphony.xwork.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:364)
    at com.opensymphony.xwork.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:216)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:190)
    at com.opensymphony.xwork.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:168)
    at com.opensymphony.xwork.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.xwork.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:115)
    at com.opensymphony.xwork.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.webwork.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:171)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.webwork.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:147)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.xwork.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:151)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:31)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.xwork.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:186)
    at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:188)
    at com.opensymphony.xwork.DefaultActionProxy.execute(DefaultActionProxy.java:113)
    at com.opensymphony.webwork.dispatcher.DispatcherUtils.serviceAction(DispatcherUtils.java:225)
    at com.opensymphony.webwork.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:202)
    at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:821)
    at com.opensymphony.webwork.dispatcher.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:88)
    at org.mortbay.jetty.servlet.WebApplicationHandler$CachedChain.doFilter(WebApplicationHandler.java:821)
    at org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicationHandler.java:471)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:568)
    at org.mortbay.http.HttpContext.handle(HttpContext.java:1530)
    at org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplicationContext.java:633)
    at org.mortbay.http.HttpContext.handle(HttpContext.java:1482)
    at org.mortbay.http.HttpServer.service(HttpServer.java:909)
    at org.mortbay.http.HttpConnection.service(HttpConnection.java:820)
    at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:986)
    at org.mortbay.http.HttpConnection.handle(HttpConnection.java:837)
    at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:245)
    at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:357)
    at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:534)

java.lang.StringIndexOutOfBoundsException: String index out of range: -1 

有人知道上面这个提示是什么意思吗？