在文件下载的时候将其保存而不是直接在浏览器上打开!

共五个类，分别如下，
package com.netec.util.download;
/**
* <p>Title:download exception </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2004</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
*/
public class DowLoadException extends Exception {
public DowLoadException() {
}
public DowLoadException(String p0) {
super(p0);
}
public DowLoadException(Throwable p0) {
super(p0);
}
public DowLoadException(String p0, Throwable p1) {
super(p0, p1);
}
}

package com.netec.util.download;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.net.URLEncoder;
import java.io.UnsupportedEncodingException;
import java.io.FileInputStream;
import java.io.*;
/**
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2004</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
*/
public class DownLoad {
private DownLoad() {
}
public static void donwload(
HttpServletRequest request,
HttpServletResponse response,
String src_fname,
String dst_fname
) throws DowLoadException {
int buffSize=1024*10;//size of buffer for read file
//try {
//Translates the file's name into application/x-www-form-urlencoded format
// dst_fname = URLEncoder.encode(dst_fname, "UTF-8");
//}
// catch (UnsupportedEncodingException ex) {
// throw new DowLoadException("error to encode the file's name ",ex);
//}
response.setContentType("application/octet-stream; charset=GBK");
response.setHeader("Content-disposition", "attachment; filename=/"" + dst_fname + "/"");
FileInputStream fis = null;
try {
fis = new FileInputStream(src_fname);
}
catch (FileNotFoundException ex) {
throw new DowLoadException("source file is not found",ex);
}
BufferedInputStream buffIn=new BufferedInputStream(fis);
byte[] byteBuff=new byte[buffSize];
try {
OutputStream outStream = response.getOutputStream();
BufferedOutputStream buffOut=new BufferedOutputStream(outStream);
int validLength=0;
//carry btye arrary
while((validLength=buffIn.read(byteBuff))!=-1){
buffOut.write(byteBuff,0,validLength);
}
buffOut.flush();
buffOut.close();
buffIn.close();
}
catch (IOException ex) {
throw new DowLoadException("file option error",ex);
}
}

}
package com.netec.util.download.servlet;
import javax.servlet.*;
import javax.servlet.http.*;
import com.netec.util.RequestNativeProxy;
import com.netec.util.download.DowLoadException;
import com.netec.util.download.DownLoad;
import java.io.*;

public class DownLoadServlet extends HttpServlet {
private static final String CONTENT_TYPE = "text/html; charset=GBK";
//Initialize global variables
public void init() throws ServletException {
}
//Process the HTTP Get request
public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//request proxy deal with "iso-8859-1"cord for getParameter method.
request=new RequestNativeProxy(request);
/*
if(!request.getMethod().trim().equalsIgnoreCase("post")){
throw new ServletException("This request must be /"post/" method. ");
}*/
String src_fname = request.getParameter("src_fname");
String dst_fname = request.getParameter("dst_fname");
//To get whole source file name
src_fname=this.getServletContext().getRealPath(src_fname);
src_fname = src_fname.replace('/',File.separatorChar);
try {
DownLoad.donwload(request, response, src_fname, dst_fname);
}
catch (DowLoadException ex) {
//throw new ServletException(ex);
ex.printStackTrace(System.out);
}
return;
}
//Clean up resources
public void destroy() {
}
}

package com.netec.util;

public class ConversionHtml {
/**
* (Constructor)
*
*/
private ConversionHtml() {
super();
}
public static String StringToHtml(String str) {
String repStr = str;
repStr = repStr.replaceAll("/r/n", "<BR>");
repStr = repStr.replaceAll("/r", "<BR>");
repStr = repStr.replaceAll("/n", "<BR>");
repStr = repStr.replaceAll(" ", " ");
return repStr;
}
public static String HtmlToString(String str) {
String repStr = str;
repStr = repStr.replaceAll("<br>|<BR>|<Br>|<bR>|<br/>|<BR/>", "/r/n");
repStr = repStr.replaceAll(" ", " ");
return repStr;
}
}
package com.netec.util;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.Principal;
import java.util.Enumeration;
import java.util.Locale;
import java.util.Map;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletInputStream;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

public class RequestNativeProxy implements HttpServletRequest {

private HttpServletRequest request;

public RequestNativeProxy(HttpServletRequest request) {
super();
this.request=request;
}

public String getAuthType() {
return request.getAuthType();
}

public Cookie[] getCookies() {
return request.getCookies();
}

public long getDateHeader(String arg0) {
return request.getDateHeader(arg0);
}

public String getHeader(String arg0) {
return request.getHeader(arg0);
}

public Enumeration getHeaders(String arg0) {
return request.getHeaders(arg0);
}

public Enumeration getHeaderNames() {
return request.getHeaderNames();
}

public int getIntHeader(String arg0) {
return request.getIntHeader(arg0);
}

public String getMethod() {
return request.getMethod();
}

public String getPathInfo() {
return request.getPathInfo();
}

public String getPathTranslated() {
return request.getPathTranslated();
}

public String getContextPath() {
return request.getContextPath();
}

public String getQueryString() {
return request.getQueryString();
}

public String getRemoteUser() {
return request.getRemoteUser();
}

public boolean isUserInRole(String arg0) {
return request.isUserInRole(arg0);
}

public Principal getUserPrincipal() {
return request.getUserPrincipal();
}

public String getRequestedSessionId() {
return request.getRequestedSessionId();
}

public String getRequestURI() {
return request.getRequestURI();
}

public StringBuffer getRequestURL() {
return request.getRequestURL();
}

public String getServletPath() {
return request.getServletPath();
}

public HttpSession getSession(boolean arg0) {
return request.getSession(arg0);
}

public HttpSession getSession() {
return request.getSession();
}

public boolean isRequestedSessionIdValid() {
return request.isRequestedSessionIdValid();
}

public boolean isRequestedSessionIdFromCookie() {
return request.isRequestedSessionIdFromCookie();
}

public boolean isRequestedSessionIdFromURL() {
return request.isRequestedSessionIdFromURL();
}

public boolean isRequestedSessionIdFromUrl() {
throw new UnsupportedOperationException();
}

public Object getAttribute(String arg0) {
return request.getAttribute(arg0);
}

public Enumeration getAttributeNames() {
return request.getAttributeNames();
}

public String getCharacterEncoding() {
return request.getCharacterEncoding();
}

public void setCharacterEncoding(String arg0)
throws UnsupportedEncodingException {
request.setCharacterEncoding(arg0);
}

public int getContentLength() {
return request.getContentLength();
}

public String getContentType() {
return request.getContentType();
}

public ServletInputStream getInputStream() throws IOException {
return request.getInputStream();
}

public String getParameter(String arg0) {
try {
if(request.getParameter(arg0)!=null) {
return new String(request.getParameter(arg0).getBytes("ISO-8859-1"));
}else {
return null;
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
return "null"+e.getMessage();
}
}

public Enumeration getParameterNames() {
return request.getParameterNames();
}

public String[] getParameterValues(String arg0) {
String[] values= request.getParameterValues(arg0);
for(int i=0;i<values.length;i++) {
try {
if(values[i]!=null) {
values[i]=new String(values[i].getBytes("ISO-8859-1"));
}else {
values[i]=null;
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
values[i]="null"+e.getMessage();
}
}
return values;
}

public Map getParameterMap() {
String newValue;
String oldValue;
String name;
Enumeration names=request.getParameterNames();
Map parameterMap=request.getParameterMap();
while(names.hasMoreElements()) {
name=(String)names.nextElement();
oldValue=(String)parameterMap.get(name);
try {
if(oldValue!=null) {
newValue=new String(oldValue.getBytes("ISO-8859-1"));
}else {
newValue=null;
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
newValue="null"+e.getMessage();
}
parameterMap.put(name,newValue);
}
return parameterMap;
}

public String getProtocol() {
return request.getProtocol();
}

public String getScheme() {
return request.getScheme();
}

public String getServerName() {
return request.getServerName();
}

public int getServerPort() {
return request.getServerPort();
}

public BufferedReader getReader() throws IOException {
return request.getReader();
}

public String getRemoteAddr() {
return request.getRemoteAddr();
}

public String getRemoteHost() {
return request.getRemoteHost();
}

public void setAttribute(String arg0, Object arg1) {
request.setAttribute(arg0,arg1);
}

public void removeAttribute(String arg0) {
request.removeAttribute(arg0);
}

public Locale getLocale() {
return request.getLocale();
}

public Enumeration getLocales() {
return request.getLocales();
}

public boolean isSecure() {
return request.isSecure();
}

public RequestDispatcher getRequestDispatcher(String arg0) {
return request.getRequestDispatcher(arg0);
}

public String getRealPath(String arg0) {
throw new UnsupportedOperationException();
}
public int getRemotePort() {

throw new UnsupportedOperationException();
}

public String getLocalName() {
throw new UnsupportedOperationException();
}

public String getLocalAddr() {
throw new UnsupportedOperationException();
}

public int getLocalPort() {
throw new UnsupportedOperationException();
}

}
web.xml 中加如下
<servlet>
<servlet-name>download</servlet-name>
<servlet-class>
com.netec.util.download.servlet.DownLoadServlet
</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>download</servlet-name>
<url-pattern>/download</url-pattern>
</servlet-mapping>

jsp页面如下
<a href="/download?src_fname=XXX.jsp&dst_fname=下载后保存的文件名" />下载</a>